bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2026–03–29
38 papers selected by
Viktor Korolchuk, Newcastle University
  1. Adaptive crosstalk between polyamine metabolism, translation, and autophagy sustains energy homeostasis in mammals during starvation: a scoping review.
  2. Real-time measurement of the ATG8 lipidation reaction by fluorescence spectroscopy.
  3. The Human Autophagy Core Complexes.
  4. Diverse mitochondrial stresses activate PINK1-PRKN/parkin mitophagy by a unified mechanism.
  5. Chemical and Molecular Strategies in Restoring Autophagic Flux in TDP-43 Proteinopathy.
  6. Revised Two-Stage Model of Preeclampsia Based on Autophagic Dysfunction: A Comprehensive Review.
  7. Exercise-Induced Exerkines Modulate Autophagy: Implications for Interorgan Crosstalk in the Hallmarks of Ageing.
  8. MCOLN1-mediated PPP3CB activation alleviates neuronal damage by promoting TFEB-dependent autophagic flux in permanent cerebral ischemia.
  9. Autoimmunity, diet and autophagy.
  10. Agomelatine Alleviates Depressive-Like Behaviors in Mice by Promoting Mitophagy in Parvalbumin-Expressing Neurons of the Hippocampal Ventral Dentate Gyrus.
  11. Bi-allelic ATG12 variants impair autophagy and cause a neurodevelopmental disorder.
  12. Suppression of ITPK1 and IPMK activities impairs mTORC1 signaling in pancreatic β-cells and implicates IP 5 in stabilizing activated mTORC1.
  13. Targeting Autophagy with Bioactive Compounds: Therapeutic Potential in Neurodegenerative Disorders.
  14. Platelet Autophagy as a Druggable Intracellular Pathway: Therapeutic Opportunities in Thromboinflammatory Diseases.
  15. Malic enzyme 2 suppresses PINK1-Parkin-mediated mitophagy by stabilizing ATAD3A via competitive interaction with TRIM25.
  16. BLOC1S1 variants cause lysosomal and autophagic defects resulting in a hypomyelinating leukodystrophy with epileptic encephalopathy.
  17. Cytosol-dwelling bacteria engage in a ubiquitination race to avoid antibacterial autophagy.
  18. Autophagy: From Molecular Mechanisms to Disease Regulation and Therapeutic Strategies.
  19. Crystal structures of Fsc1, a novel autophagy factor that mediates autophagosome-vacuole fusion in fission yeast.
  20. mTOR signaling regulates demand-adapted hematopoiesis and metabolic reprogramming required for an effective cellular immune response in Drosophila melanogaster larvae.
  21. Lysosomal salvage of neuronal lipids enables glial infiltration of synaptic regions.
  22. Cell-intrinsic mTOR/LET-363 influences morphological aging of the ALM touch receptor neuron in Caenorhabditis elegans.
  23. Survey of the human proteostasis network: the ubiquitin-proteasome system.
  24. ULK1 drives NDP52-mediated selective autophagic degradation of MHC-I to promote immune evasion in HPV-positive head and neck cancer.
  25. Cyclin C promotes pancreatic developmentand suppresses cancer initiation by maintenance of the autophagy-lysosome pathway.
  26. Optineurin calibrates STING-mediated type I interferon response.
  27. The Effect of Mechanical Loading on Mitophagy in Aged Myoblasts.
  28. Cardiac REDD1 alters glucose and fatty acid metabolic gene expression via an mTORC1-independent, PPARα-dependent mechanism and drives hypertrophic growth.
  29. Mammalian target of rapamycin in chronic liver disease and the potential for therapeutic manipulation.
  30. Cell biology: Killing the prisoner escaping from mitochondria.
  31. Crosstalk between autophagy and ferroptosis in liver diseases (Review).
  32. Repair condensates and lipid domains in lysosome integrity.
  33. Activation of Mitophagy by Kinetin Mitigates Coal-Silica Mixed Dust-Induced Pulmonary Fibrosis via Modulating Macrophage Mitochondrial Function in Mice.
  34. RFC4 drives temozolomide resistance in glioblastoma by activating STK38-BECN1-dependent autophagy.
  35. VAMP8 function reveals tight linkage between endocytic recycling and endocytosis.
  36. Binding of 14-3-3 stabilises recombinant AMPKγ2-containing complexes.
  37. MAP2K6 directly phosphorylates BCL2L13 to mediate mitophagy for suppressing tumorigenicity.
  38. A quantitative cell-based reporter links TDP-43 aggregation and dysfunction to define pathogenic mechanisms.
  1. Amino Acids. 2026 Mar 24.
    Adaptive crosstalk between polyamine metabolism, translation, and autophagy sustains energy homeostasis in mammals during starvation: a scoping review.
    Kayhan Karimi, Sigrid C Roberts, Nicola S Carter, Sebastian J Hofer, Reza Karimi.
      Mammalian cells tightly regulate the shift between catabolism and anabolism to maintain energy homeostasis during starvation. Among other adaptations, cells adapt to nutrient restriction by downregulating translation, the most energy consuming cellular process, and inducing autophagy. Polyamines are ubiquitous small polycationic endogenous metabolites indispensable for cellular growth and viability. They regulate both autophagy and translation processes, coordinating an intriguing metabolic hub during cellular adaptation to starvation. Recent studies have highlighted a complex role for polyamines during starvation and a growing body of evidence underscores various nutrients and nutrient-sensing pathways that modulate autophagy through their influence on the mammalian target of rapamycin complex 1 (mTORC1) signaling. mTORC1 is a master regulator of cellular anabolism, including translation. Less explored is how these coordinated systems adapt and respond to starvation. This scoping review explores how changes in polyamine metabolism and related molecules orchestrate the adaptive crosstalk between autophagy, mTORC1, and translation to ensure that the mammalian cell conserves energy to maintain essential cellular functions during starvation. Our review highlights that spermidine and one of its major cellular targets, translation initiation factor 5A (eIF5A), facilitate translation of transcription factor EB (TFEB) to induce autophagy during starvation. Starvation suppresses mTORC1 activity, leading to reduced ribosome biogenesis and translation while promoting autophagy to meet cellular energy demands. We discuss the adaptive mechanisms by which reduced levels of acetyl-CoA, amino acids, EP300, glucose, insulin, and S-adenosylmethionine inhibit mTORC1 and simultaneously induce autophagy. Additionally, we describe the adaptive role that glucagon, Sestrin2, and urea play to inhibit mTORC1 and how eIF5A, glucagon, spermidine, and TFEB induce autophagy.
    Keywords:  Amino acids; Autophagy; Mammals; Spermidine; Translation; mTORC1
    DOI:  https://doi.org/10.1007/s00726-026-03512-6
  2. Methods Enzymol. 2026 ;pii: S0076-6879(26)00011-X. [Epub ahead of print]728 327-345
    Real-time measurement of the ATG8 lipidation reaction by fluorescence spectroscopy.
    Wenxin Zhang, Sharon A Tooze, Taki Nishimura.
      Autophagy is a highly conserved intracellular degradation pathway, in which damaged organelles and/or dysfunctional cytosolic components are enveloped via double-membraned autophagosomes and subsequently delivered to lysosomes for degradation. The ubiquitin-like ATG8 family proteins (LC3s and GABARAPs) are covalently conjugated to phosphatidylethanolamine (PE) on autophagic membranes via ubiquitin-like conjugation systems, a process known as ATG8 lipidation. Lipidated ATG8 is the most widely used membrane marker for autophagosomes, and its flux is commonly used as a readout for autophagy activity. In vitro reconstitution of the ATG8 lipidation reaction is well-established, and the end-point reaction is typically resolved by SDS-PAGE. This endpoint readout is not suitable to monitor the kinetics of this reaction, and tools to study this process have been lacking. Here, we describe a real-time assay to measure the ATG8 lipidation reaction. This approach not only reveals the subsequential formation of covalently bound intermediates of ATG8 with the E1 (ATG7) and E2 (ATG3) enzymes, as well as ATG8-PE itself, but also provides insights into the interaction interface of ATG8 with proteins and membranes during the conjugation reaction.
    Keywords:  3-diazol-4-yl (NBD); 7-nitrobenz-2-oxa-1; ATG8 lipidation; Autophagy; Fluorescence spectroscopy; Liposomes; Site-specific labeling; in vitro reconstitution
    DOI:  https://doi.org/10.1016/bs.mie.2026.01.011
  3. Annu Rev Biochem. 2026 Mar 25.
    The Human Autophagy Core Complexes.
    James H Hurley.
      The autophagy core machinery carries out the fundamental reactions of autophagosome biogenesis across all forms of bulk and selective macroautophagy. In humans, the core complexes consist of the ULK1 complex (ULK1C), the class III phosphatidylinositol 3-kinase complex I (PI3KC3-C1), the ATG8 proteins and the ATG8ylation machinery, the phosphatidylinositol 3-phosphate (PI3P)-sensing WIPI proteins, the lipid transporter ATG2, and the lipid scramblase and initiation scaffold ATG9. These complexes form a web of interactions that can be initiated by clustering of the FIP200 subunit of ULK1C but also by PI3KC3-C1 or WIPI2. Upon autophagy induction, these interactions are intensified by feed-forward signaling loops. These loops are amplified by WIPI-PI3P interactions and the conjugation of ATG8 proteins to the membrane by the ATG12-ATG5-ATG16L1 complex. Autophagosomes are seeded by ATG9 vesicles, which accrue initiation machinery on their surface and dock onto a PI3P-positive domain of the endoplasmic reticulum known as the omegasome. The omegasome contact site is the focal point for autophagosome growth, which is fed by lipid transport through the ATG2 bridge-like lipid transporter. The core complexes function in a dynamic manner, which makes autophagy vulnerable to stalling when dynamism fails. Disassembly and dissociation of the machinery, which is promoted at least in part by ULK1, is likely to be as important as assembly.
    DOI:  https://doi.org/10.1146/annurev-biochem-072425-030036
  4. Autophagy. 2026 Mar 22. 1-2
    Diverse mitochondrial stresses activate PINK1-PRKN/parkin mitophagy by a unified mechanism.
    Julia A Thayer, Derek P Narendra.
      Mutations in PINK1 and PRKN/parkin are the leading recessive causes of Parkinson disease (PD). Together PINK1 and PRKN form a mitophagy pathway for clearing damaged mitochondria from the cell. It was unclear, however, whether diverse forms of mitochondrial damage activate the PINK1-PRKN pathway through a unified mechanism. Recently, we demonstrated that loss of mitochondrial membrane potential (MMP) leads to the stabilization and activation of PINK1 under a wide range of mitochondrial stressors, including mitochondrial protein misfolding. Mechanistically, we suggest that the MMP is required at a key step of PINK1 import into mitochondria, in which PINK1 is transferred between the translocases of the outer and inner mitochondrial membranes. Consistent with this model, retention of active PINK1 of the outer membrane requires the translocase of the outer mitochondrial membrane (TOMM) complex, whereas import of PINK1 from the outer to inner membrane requires the TIMM23 (translocase of inner mitochondrial membrane 23) complex. Notably, chronic disruption of the TIMM23 complex is sufficient to stabilize active PINK1 in the TOMM complex, phenocopying MMP loss. Together, our findings suggest PINK1 primarily senses catastrophic drops in a mitochondrion's MMP: a dead-end for the mitochondrion's continued biogenesis.
    Keywords:  Autophagy; PARK2; PARK6; mitochondria unfolded protein response; mitochondrial quality control
    DOI:  https://doi.org/10.1080/15548627.2026.2646238
  5. Molecules. 2026 Mar 10. pii: 924. [Epub ahead of print]31(6):
    Chemical and Molecular Strategies in Restoring Autophagic Flux in TDP-43 Proteinopathy.
    Angelo Jamerlan, John Hulme.
      The cytoplasmic accumulation of TDP-43 aggregates remains a persistent pathological hallmark of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and limbic-predominant age-related TDP-43 encephalopathy (LATE). The cell's natural clearance mechanisms, the Ubiquitin-Proteasome System (UPS) and the autophagy-lysosome pathway (ALP), are hypothesized to fail, at least in part, due to the sequestration of key components of these pathways by pathological TDP-43 species, thereby impairing autophagosome-lysosome fusion and lysosomal competence. Classical autophagic activators (e.g., rapamycin) can initiate upstream steps in the pathway but cannot address downstream flux bottlenecks, limiting their ability to restore effective TDP-43 clearance. This review revisits classical strategies and discusses newer approaches to modulate TDP-43 clearance, including transcription factor EB (TFEB) activators, proteolysis-targeting chimeras (PROTACs), and antisense oligonucleotides (ASOs). We propose that adopting multi-targeting strategies and developing better biomarkers are vital for clinical success.
    Keywords:  PROTACs; TDP-43 proteinopathy; amyotrophic lateral sclerosis; autophagic flux; autophagy-lysosome pathway; frontotemporal dementia; neurodegeneration; proteostasis
    DOI:  https://doi.org/10.3390/molecules31060924
  6. Biomolecules. 2026 03 15. pii: 441. [Epub ahead of print]16(3):
    Revised Two-Stage Model of Preeclampsia Based on Autophagic Dysfunction: A Comprehensive Review.
    Atsushi Furuta, Tomoko Shima, Takashi Nishigori, Kiyotaka Yamada, Haruka Nunomura, Mihoko Yoshida, Shina Sakaguchi, Takuya Majima, Akemi Yamaki-Ushijima, Kanto Shozu, Sayaka Tsuda, Shibin Cheng, Surendra Sharma, Akitoshi Nakashima.
      A revised two-stage model of preeclampsia is proposed, centering on an autophagy-dependent requirement for extravillous trophoblast entry into the proximal one-third of the myometrium. The One-Third Myometrium Enigma, introduced here, denotes the unresolved physiological rule that early placentation requires trophoblasts to traverse decidua and reach the proximal one-third of myometrium under hypoxia and nutrient scarcity. The hypothesis posits a timed rise in basal autophagy to sustain trophoblast energy homeostasis and invasion, accompanied by TFEB-driven lysosomal programs that enable villous cytotrophoblast syncytialization. Autophagic dysfunction could contribute to shallow invasion, chronic placental hypoxia, fetal growth restriction, and release of placental injury signals preceding maternal syndrome. Potential failure modes include reduced autophagic flux due to inhibition of autophagosome to lysosome fusion or mistimed persistence of hypoxia signaling, such as prolonged HIF-1α activity. Collectively, this evidence suggests that impaired autophagy is a testable contributor to preeclampsia pathogenesis. Predictions include early risk stratification with circulating autophagy markers and extracellular vesicle microRNAs, and therapeutic benefit from autophagy modulation that targets AMPK or mTOR or activates TFEB with safety constraints. This framework reframes preeclampsia as a disorder of placental quality control and specifies where and when autophagy may be required.
    Keywords:  TFEB; autophagy; preeclampsia
    DOI:  https://doi.org/10.3390/biom16030441
  7. Int J Mol Sci. 2026 Mar 18. pii: 2746. [Epub ahead of print]27(6):
    Exercise-Induced Exerkines Modulate Autophagy: Implications for Interorgan Crosstalk in the Hallmarks of Ageing.
    Qi Deng, Jielun Huang, Cenyi Wang, Jiling Liang.
      Population aging and widespread sedentary lifestyles have increased the prevalence of chronic non-communicable diseases, many of which are linked to progressive disruptions of cellular homeostasis. Autophagy, a conserved cellular degradation and recycling pathway, plays a central role in maintaining metabolic flexibility, proteostasis, and organ function. However, aging and physical inactivity impair autophagic regulation, thereby contributing to the development of sarcopenia, cardiovascular diseases, metabolic disorders, and neurodegenerative diseases. Physical exercise is a non-pharmacological intervention that can restore autophagic activity and confer systemic health benefits in multiple preclinical and clinical contexts. Increasing evidence indicates that these benefits are mediated not only by local tissue adaptations but also by complex inter-organ communication. Central to this process are exercise-induced bioactive factors, collectively termed exerkines, including myokines, cardiokines, adipokines, hepatokines, osteokines, and circulating miRNAs. Rather than acting independently, exerkines form an integrated signaling network that fine-tunes autophagic flux across multiple tissues. Exerkine-mediated regulation of autophagy involves key pathways such as AMPK/mTOR, FoxO, SIRT1, ULK1, and TFEB, thereby coordinating energy metabolism, mitochondrial quality control, inflammation, and protein turnover in skeletal muscle, heart, liver, adipose tissue, bone, and the central nervous system. This review summarizes current evidence on representative exerkines and their roles in autophagy-dependent inter-organ crosstalk, highlighting the exercise-exerkine-autophagy axis as a promising target for preventing and managing chronic diseases.
    Keywords:  autophagy; exercise; exerkines; miRNAs; sarcopenia
    DOI:  https://doi.org/10.3390/ijms27062746
  8. Acta Pharmacol Sin. 2026 Mar 24.
    MCOLN1-mediated PPP3CB activation alleviates neuronal damage by promoting TFEB-dependent autophagic flux in permanent cerebral ischemia.
    Shi-Qi Liu, Yue-Yang Liu, Xiao-Xiao Fu, Pei-Rui Cui, Xin Wang, Sai-Qian Wang, Chun-Fu Wu, Li-Hui Wang, Jing Luo, Jing-Yu Yang.
      We previously reported that transcription factor EB (TFEB) plays a crucial role in regulating the ischemic stroke (IS)-mediated dynamic changes of autophagic flux. Protein phosphatase 3 (PPP3) may regulate the transcriptional activity of TFEB. However, the main isoform of the PPP3 catalytic subunit (PPP3C) involved in TFEB activation, the PPP3-binding site in TFEB, and the upstream regulatory mechanism of PPP3 activation after cerebral ischemia are still unknown. Here, we show that the interaction between TFEB and PPP3 catalytic subunit B (PPP3CB), but not PPP3CA, is strengthened after IS. Knockdown of PPP3CB, but not PPP3CA, significantly inhibited the oxygen glucose deprivation (OGD)-induced increase in the transcriptional activity of TFEB, blocked autophagic flux, and exacerbated neuronal death. Furthermore, the YLAVP peptide, which blocks the LxVP motif-binding site of PPP3C, repressed TFEB transcriptional activity and autophagic flux, and exacerbated neuronal death after OGD. Treatment with ML-SI1, which inhibits the lysosomal calcium channel MCOLN1, blocked the OGD-induced enhancement of TFEB transcriptional activity and autophagic flux, and further aggravated neuronal death. These effects were partly reversed by the MCOLN1 agonist ML-SA1. The PPP3 inhibitor cyclosporin A (CsA) abolished the ML-SA1-induced TFEB transcriptional activation and reduced neuronal death. Our findings identify for the first time that MCOLN1-mediated-PPP3CB activation alleviates neuronal damage by promoting TFEB-dependent autophagic flux in permanent cerebral ischemia. The LxVP motif is required for the interaction between PPP3 and TFEB in response to OGD. This study provides an in-depth insight into the mechanisms underlying TFEB-mediated activation of autophagic flux following IS. Schematic diagram showing how MCOLN1-mediated activation of PPP3CB reduces neuronal damage by promoting TFEB-dependent autophagic flux in permanent cerebral ischemia.
    Keywords:  LxVP motif-binding site; MCOLN1; autophagy-lysosomal pathway; protein phosphatase 3 catalytic subunit B; transcription factor EB
    DOI:  https://doi.org/10.1038/s41401-026-01762-4
  9. Autoimmun Rev. 2026 Mar 20. pii: S1568-9972(26)00054-6. [Epub ahead of print] 104040
    Autoimmunity, diet and autophagy.
    Sébastien Blaise, Sylviane Muller.
      Autophagy is a highly conserved lysosomal recycling pathway that couples nutrient availability to cellular quality control and immune regulation. Accumulating evidence identifies autophagy as a central mechanistic interface through which dietary exposures influence metabolic inflammation and the maintenance or breakdown of immune tolerance in autoimmune diseases. This review synthesizes current molecular and cellular insights into how nutrition modulates autoimmune susceptibility and disease activity by shaping autophagic pathways across immune and metabolic tissues. Dietary signals exert bidirectional and context-dependent effects on immune homeostasis. Deficiencies in key micronutrients, including vitamin D, zinc, selenium, and omega-3 fatty acids, can impair regulatory immune circuits and promote pro-inflammatory cytokine profiles. Conversely, overnutrition, obesity, and Westernized dietary patterns drive chronic low-grade inflammation, compromise epithelial barrier integrity, and remodel the gut microbiota, thereby amplifying systemic immune activation and autoantibody-related pathways. The review describes major autophagy programs and highlights their roles in lymphocyte survival and memory, antigen presentation, and cytokine regulation. Genetic and experimental evidence indicate that defective autophagy and lysosomal dysfunction can alter antigen handling and perpetuate pathological immune activation. Nutritional regulation of autophagy is discussed through nutrient-sensing pathways, particularly mechanistic target of rapamycin complex 1, AMP-activated protein kinase, and sirtuin 1. Fasting-based strategies and time-restricted eating may enhance autophagic competence, whereas high-glycemic, obesogenic diets can suppress autophagy and intensify oxidative and endoplasmic reticulum stress. Finally, a precision immunonutrition framework is proposed that integrates genetic susceptibility, microbiota features, metabolic profiling, and autophagy biomarkers to guide individualized, adjunctive interventions in autoimmune diseases.
    Keywords:  Autophagy; Immunonutrition; Inflammation; Nutrients; Prevention/management of autoimmune diseases
    DOI:  https://doi.org/10.1016/j.autrev.2026.104040
  10. Neuropharmacology. 2026 Mar 24. pii: S0028-3908(26)00118-8. [Epub ahead of print] 110945
    Agomelatine Alleviates Depressive-Like Behaviors in Mice by Promoting Mitophagy in Parvalbumin-Expressing Neurons of the Hippocampal Ventral Dentate Gyrus.
    Suhong Ye, Qiaolu Xu, Ling Bao, Azhar Badry Hussein, Qinglin Lu, Xia Yuan, Nashwa Amin, Marong Fang.
       BACKGROUND: Major depressive disorder (MDD) is highly prevalent, but some patients are refractory to conventional treatments. Mitochondrial dysfunction, impaired mitophagy, and parvalbumin (PV)-expressing hippocampal neuron deficits are linked to MDD pathogenesis, while agomelatine's antidepressant mechanism involving these elements remains unclear.
    AIM: This study aimed to clarify whether agomelatine alleviates depressive-like behaviors in mice by promoting mitophagy in PV neurons of the hippocampal ventral dentate gyrus (vDG).
    METHODS: Male C57BL/6J and Pvalb-cre::Ai14 mice underwent chronic unpredictable mild stress (CUMS) for depression modeling. Groups included Control, CUMS, CUMS+Fluoxetine (FLX), CUMS+Agomelatine (AGO), CUMS+AGO+3-Methyladenine (autophagy inhibitor), CUMS+AGO+Rapamycin (an mTORC1 inhibitor that indirectly promotes autophagy in a cell-type-dependent manner), and CUMS with vDG-targeted AAV-Beclin1 overexpression (oeBeclin1)±AGO. Behavioral tests (TST, FST, SPT, OFT, SIT) and molecular/morphological analyses (Western blotting, IF, RT-qPCR, DHE staining, TEM, Golgi staining) were conducted.
    RESULTS: CUMS induced depressive-like behaviors and reduced PV neuron density. AGO's performance is no less effective than FLX. Mechanistically, it upregulated autophagy-related proteins (Beclin1, ATG5, LC3II/I) and downregulated p62. oeBeclin1 synergized with agomelatine to improve mitochondrial morphology, reduce ROS, and inhibit neuroinflammation.
    CONCLUSION: In conclusion, agomelatine alleviates CUMS-induced depressive-like behaviors in mice, which is associated with the promotion of mitophagy in vDG PV neurons of the hippocampus, mitigating mitochondrial damage and neuroinflammation. This uncovers a novel mechanism for its efficacy and highlights targeted mitophagy activation as a promising MDD therapeutic strategy.
    Keywords:  Agomelatine; Ai14 mice; Mitophagy; PV neuron; chronic unpredictable mild stress
    DOI:  https://doi.org/10.1016/j.neuropharm.2026.110945
  11. Am J Hum Genet. 2026 Mar 26. pii: S0002-9297(26)00112-6. [Epub ahead of print]
    Bi-allelic ATG12 variants impair autophagy and cause a neurodevelopmental disorder.
    James Lambton, Shotaro Asano, Yuxiang Huang, Fumi Suomi, Tomoya Eguchi, Cassidy Petree, Kevin Huang, Magali Prigent, Aliza Imam, Thomas J McCorvie, Daniel Warren, Emma Hobson, Helen McCullagh, Doriana Misceo, Anna Bjerre, Marie F Smeland, Claus Klingenberg, Eirik Frengen, Swati Naik, Gavin Ryan, Annapurna Sudarsanam, Katherine Foster, Pradeep Vasudevan, Rajib Samanta, Fatima Rahman, Shazia Maqbool, Vrajesh Udani, Stephanie Efthymiou, Henry Houlden, Robert McFarland, Jack J Collier, Reza Maroofian, Wyatt W Yue, Gaurav K Varshney, Daniel J Klionsky, Renaud Legouis, Thomas G McWilliams, Noboru Mizushima, Monika Oláhová, Charlotte L Alston, Robert W Taylor.
      Autophagy is an essential developmental and homeostatic process, defined by the endolysosomal degradation of intracellular components and pathogens. Dysfunctional autophagy is implicated in complex human disease, yet reports of congenital autophagy disorders were considered exceedingly rare until the recent report of several unrelated families with bi-allelic variants in the core autophagy effector ATG7, complementing the report of two individuals harboring ATG5 variants. We now report six affected individuals from five families with bi-allelic ATG12 variants with complex neurological phenotypes overlapping those seen in individuals with pathogenic variants in ATG5 and ATG7: developmental delay, intellectual disability, congenital ataxia, hypotonia, and seizures with cerebellar vermis hypoplasia evident on neuroradiological imaging. Structural modeling implicated a potential disruption of the ATG12-ATG5-ATG16N-ATG3 complex. Biochemical analyses of primary fibroblasts confirmed the loss of stable ATG12-ATG5 conjugate in one family and altered autophagic flux in one unrelated family. The HaloTag processing assay in HeLa cells demonstrated a decrease in ATG12-ATG5 conjugate and reduced autophagic flux in response to starvation. Complementation studies demonstrated that equivalent missense atg12 variants were unable to fully recover the biochemical defect in atg12-null yeast, with microscopy analysis demonstrating a reduced delivery of autophagy substrates to the yeast's degradative compartment. Zebrafish studies confirmed that Atg12 is required for normal growth, brain development, and neural function. Collectively, our findings underscore the pivotal role of autophagy in maintaining human neural integrity, emphasize an emerging group of congenital autophagy disorders, and expand our understanding of adaptive homeostasis in human health and disease.
    Keywords:  ATG12; ataxia; autophagy; cerebellar hypoplasia; global developmental delay
    DOI:  https://doi.org/10.1016/j.ajhg.2026.03.002
  12. bioRxiv. 2026 Mar 07. pii: 2026.03.04.709646. [Epub ahead of print]
    Suppression of ITPK1 and IPMK activities impairs mTORC1 signaling in pancreatic β-cells and implicates IP 5 in stabilizing activated mTORC1.
    Clarisse Iradukunda, Edward A Salter, Dilipkumar Uredi, Xiaodong Wang, Andrzej Wierzbicki, Lucia E Rameh.
      mTORC1 integrates growth factor and nutrient signals to regulate cellular metabolism, yet there are no metabolites known to directly regulate mTORC1 activity in cells. Cryo-EM studies revealed that inositol hexakisphosphate (IP 6 ) associates with the FAT domain of mTOR, suggesting that inositol phosphates may directly modulate mTOR activity. We previously showed that higher-order inositol phosphates enhance mTORC1 kinase activity and stability in vitro. Here, we investigated whether inositol phosphate metabolism regulates mTORC1 signaling in pancreatic β-cells. Suppression or acute inhibition of inositol phosphate multikinase (IPMK), as well as knockdown of inositol trisphosphate kinase 1 (ITPK1), selectively reduced cellular IP 5 levels without altering IP 6 and resulted in impaired basal and insulin-stimulated mTORC1 signaling, particularly under physiological glucose and low growth factor conditions. Combined inhibition of IPMK and ITPK1 nearly abolished IP 5 and reduced IP 6 , demonstrating that these enzymes compensate to supply IP 5 for IP 6 synthesis. Importantly, depletion of IP 5 did not impair PI3K/Akt activation but accelerated termination of the mTORC1 signal, indicating a role for IP 5 in stabilizing the active mTORC1 complex. Reduction of inositol phosphate levels did not prevent insulin- or glucose-induced mTORC1 activation, revealing that IP 5 primarily regulates signal persistence rather than initiation. Together, these findings identify IP 5 as a metabolic regulator that prolong mTORC1 activity in β-cells, providing a mechanism by which cellular metabolic state modulates sustained mTORC1 signaling.
    Significance Statement: mTORC1 is a central metabolic regulator whose chronic activation contributes to metabolic disease, yet mechanisms that sustain mTORC1 activity after its activation are poorly understood. We show that enzymes controlling inositol phosphate metabolism regulate the stability of mTORC1 signaling in pancreatic β-cells by maintaining cellular levels of inositol pentakisphosphate (IP 5 ). Reducing IP 5 impairs basal and sustained mTORC1 signaling without affecting upstream growth factor or energy-sensing pathways, revealing a mechanism that controls signal duration rather than activation. These findings identify IP 5 as a metabolic regulator of mTORC1 and suggest that targeting inositol phosphate metabolism may provide a strategy to modulate mTORC1 activity in metabolic disease.
    DOI:  https://doi.org/10.64898/2026.03.04.709646
  13. Curr Neuropharmacol. 2026 Mar 16.
    Targeting Autophagy with Bioactive Compounds: Therapeutic Potential in Neurodegenerative Disorders.
    Arun Kumar Singh, Anuradha Kush, Bharat Bhushan, Meenakshi Dhanawat, Pravesh Kumar Sharma.
      Neurodegenerative disorders (NDs), including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are characterized by the accumulation of misfolded proteins and impaired cellular clearance mechanisms. Autophagy, a critical lysosomedependent degradative pathway, plays a vital role in maintaining proteostasis and neuronal health. Dysregulation of autophagy has been implicated in the pathogenesis of multiple NDs, making it a promising therapeutic target. This review comprehensively examines the molecular mechanisms of autophagy and its dysfunction across major NDs. Furthermore, it highlights the potential of bioactive compounds such as flavonoids, alkaloids, polyphenols, and terpenoids to modulate autophagic flux, thereby promoting the clearance of toxic protein aggregates like amyloid-β, tau, and α- synuclein. Emerging strategies, including nanotechnology-based delivery systems, are also discussed for enhancing the bioavailability and efficacy of these compounds. The evidence suggests that pharmacological or natural induction of autophagy may alleviate neurodegenerative pathology, though context- and stage-specific modulation is essential. This work underscores the therapeutic promise of autophagy-enhancing bioactives and calls for further research into their clinical applications.
    Keywords:  Neurodegenerative disorders; alzheimer’s disease; amyotrophic lateral sclerosis; autophagy; bioactive compounds.; parkinson’s disease
    DOI:  https://doi.org/10.2174/011570159X408653251130061347
  14. Pharmaceutics. 2026 Feb 27. pii: 293. [Epub ahead of print]18(3):
    Platelet Autophagy as a Druggable Intracellular Pathway: Therapeutic Opportunities in Thromboinflammatory Diseases.
    Ting-Lin Yen, Jing-Shiun Jan, Ruei-Dun Teng, Pi-Chan Ko, Rajeev Taliyan, Chih-Hao Yang, Jui-Ming Sun, Joen-Rong Sheu.
      Platelet hyperreactivity is a central driver of thromboinflammatory diseases, including ischemic stroke, cardiovascular disorders, and autoimmune conditions. Current antiplatelet therapies primarily target surface receptors or coagulation pathways and are frequently limited by drug resistance, bleeding risk, and inadequate control of metabolically or inflammation-driven platelet dysfunction. Emerging evidence reveals that platelets possess a fully functional autophagic machinery that critically regulates mitochondrial quality, redox balance, granule secretion, cytoskeletal remodeling, and activation thresholds. This intracellular pathway represents a previously underrecognized but highly druggable regulatory axis in platelet biology. In this review, we examine the molecular framework governing autophagy in platelets, with emphasis on mTOR, AMPK, PI3K/AKT, and mitophagy signaling networks, and discuss how basal and activation-induced autophagy determine thrombotic behavior under physiological and pathological conditions. We then integrate clinical and preclinical evidence demonstrating how dysregulated platelet autophagy contributes to thrombotic risk in ischemic stroke, cardiovascular disease, metabolic disorders, and autoimmune diseases. Importantly, we highlight how pharmacological agents, including mTOR inhibitors, AMPK activators, natural autophagy enhancers, and lysosomal inhibitors, modulate platelet function through autophagy-dependent mechanisms. These findings position platelet autophagy as a promising intracellular therapeutic target that complements conventional antiplatelet strategies. We further discuss the translational challenges of autophagy-targeted therapy, including context dependency, lack of platelet-specific modulators, delivery strategies, and the need for reliable biomarkers to guide personalized intervention. By framing platelet autophagy as a druggable pathway rather than a biological curiosity, this review outlines a precision-targeted therapeutic framework for managing thromboinflammatory diseases through intracellular modulation of platelet behavior.
    Keywords:  antiplatelet resistance; drug targeting; intracellular therapeutics; pharmacological modulation; platelet autophagy; precision medicine; thromboinflammation
    DOI:  https://doi.org/10.3390/pharmaceutics18030293
  15. Cell Death Dis. 2026 Mar 24.
    Malic enzyme 2 suppresses PINK1-Parkin-mediated mitophagy by stabilizing ATAD3A via competitive interaction with TRIM25.
    Qian Liu, Lei Su, Xiaoyun Wei, Shijie Lin, Lingkai Huang, Lige Hou, Yanhong Wang, Liubing Hu, Junyang Tan, Jing Qiao, Qinghua Zhou, Yi Ma, Wenjun Wang, Jianshuang Li.
      Malic enzyme 2 (ME2), a pivotal enzyme related to the tricarboxylic acid (TCA) cycle, has been implicated in multiple cancers due to its overexpression and metabolic role in regulating the NADP+/NADPH balance. Malic enzyme 2 has been reported to regulate mitochondrial biogenesis and fusion; however, whether malic enzyme 2 participates in mitophagy regulation has remained unclear. Here, we reported that malic enzyme 2 depletion enhances PINK1-Parkin-mediated mitophagy. Mechanistically, ME2 competes with the E3 ubiquitin ligase TRIM25, disrupting its binding with ATPase family AAA domain-containing protein 3 A (ATAD3A), a mitochondrial protein crucial for the degradation of PINK1. Loss of malic enzyme 2 strengthens the TRIM25-ATAD3A interaction, resulting in ATAD3A ubiquitination and proteasomal degradation. The consequent PINK1 accumulation drives mitophagy activation. Hyperactivated mitophagy caused by malic enzyme 2 knockdown disrupts mitochondrial homeostasis, which suppresses the proliferative capacity of hepatoma cells. Moreover, pharmacological inhibition of mitophagy partially rescued the suppressed cell proliferation in the malic enzyme 2-knockdown cells. Our findings reveal a previously unrecognized role of malic enzyme 2 in mitochondrial quality control and highlight the ME2-ATAD3A-PINK1 axis as a potential regulatory node for mitophagy modulation.
    DOI:  https://doi.org/10.1038/s41419-026-08623-2
  16. Am J Hum Genet. 2026 Mar 25. pii: S0002-9297(26)00110-2. [Epub ahead of print]
    BLOC1S1 variants cause lysosomal and autophagic defects resulting in a hypomyelinating leukodystrophy with epileptic encephalopathy.
    Raffaella De Pace, Carlos A Dominguez Gonzalez, Chad D Williamson, Guy Helman, Leslie E Sanderson, Brianna Disanza, Nicole Hsiao-Sánchez, Amy Pizzino, Kayla Muirhead, Joshua L Bonkowsky, Ryan J Taft, Nouriya A Sannaa, Patricia Dias, Ana Sofia Quintas, Mehmet Burak Mutlu, Hasan Bas, Hasan Oztürk, Majid Mojarrad, Masoome Alerasool, Shahriar Sheikhani, Hayder Kadhim Jabbar, Awatif Hameed Issa, Henry Houlden, Emir Zonic, Tahsin Stefan Barakat, Kornelia Tripolski, Antonio Romito, Eden Teferedegn, Arastoo Vossough, Matthew T Whitehead, Elizabeth Bhoj, Rebecca C Ahrens-Nicklas, Cas Simons, Ernst Wolvetang, Tjakko J van Ham, Aida M Bertoli-Avella, Reza Maroofian, Juan S Bonifacino, Adeline Vanderver.
      BLOC1S1 encodes a subunit shared by the BLOC-1 and BLOC-one-related complex (BORC) hetero-octameric complexes that regulate various endolysosomal processes. Here, we report the identification of seven distinct variants in BLOC1S1 in 11 individuals from seven independent families presenting with early psychomotor delay, hypotonia, spasticity, epileptic encephalopathy, optic atrophy, and leuko-axonopathy with hypomyelination. A subset of the affected individuals also have features of hypopigmentation and ocular albinism that are similar, although milder, than those of individuals with BLOC-1-related Hermansky-Pudlak syndrome. Functional analyses show that BLOC1S1 knockout (KO) impairs the anterograde transport of lysosomes and autophagy in both non-neuronal cells and induced pluripotent stem cell (iPSC)-derived neurons. Transfection experiments reveal that most BLOC1S1 variants exhibit reduced expression, decreased assembly with other BORC/BLOC-1 subunits, and/or impaired restoration of lysosome transport and autophagy in BLOC1S1-KO cells. Additionally, we show that KO of BLOC1S1 reduces pigmentation in a melanocytic cell line and that five of the BLOC1S1 variants partially or fully restore pigmentation. These findings provide genetic, clinical, and functional evidence that loss of function (LoF) of BLOC1S1 leads to more pronounced deficits in BORC than BLOC-1 function. We conclude that the bi-allelic BLOC1S1 variants characterized here primarily result in a neurological disorder with prominent leukodystrophy, similar to the recently reported condition caused by variants in the BORCS8 subunit of BORC. Together, these findings establish BORCopathies as a distinct disease entity.
    Keywords:  BLOC-1; BLOC1S1; BORC; autophagy; leukodystrophy; lysosomes; neurodevelopmental disorder
    DOI:  https://doi.org/10.1016/j.ajhg.2026.02.024
  17. Autophagy. 2026 Apr;22(4): 645-647
    Cytosol-dwelling bacteria engage in a ubiquitination race to avoid antibacterial autophagy.
    Hana Popelka, Daniel J Klionsky.
      One of the defense mechanisms of host cells against bacterial pathogens is antibacterial macroautophagy/autophagy that relies on ubiquitination of a pathogen for recognition by specific receptors that deliver the pathogen to phagophores. RNF213 is an E3 ligase that mediates ubiquitination of lipopolysaccharides (LPS) on bacteria dwelling in the host cytosol. However, one type of cytosol-invading bacteria, Shigella flexneri, evolved a mechanism through which it can avoid LPS ubiquitination. S. flexneri employs IpaH1.4, an effector protein with E3 ligase activity that ubiquitinates RNF213 for proteasomal degradation. Here, we discuss a study that discovered this S. flexneri strategy, and revealed by cryo-EM that the IpaH1.4 leucine-rich repeat recognizes and binds the RNF213 RING domain. The mass spectrometry data showed that IpaH1.4 targets several other RING-containing E3 ligases implicated in inflammation and immunity, which opens a new field for xenophagy.Abbreviations: cryo-EM, cryo-electron microscopy; LPS, lipopolysaccharide; LRR, leucine-rich repeat; LUBAC, linear ubiquitin chain assembly complex; NEL, novel E3 ligase; OPTN, optineurin.
    Keywords:  Cryo-EM; IpaH; RNF213 RING finger; Shigella flexneri; lipopolysaccharides
    DOI:  https://doi.org/10.1080/15548627.2026.2624823
  18. Curr Issues Mol Biol. 2026 Mar 07. pii: 285. [Epub ahead of print]48(3):
    Autophagy: From Molecular Mechanisms to Disease Regulation and Therapeutic Strategies.
    Huijie Yang, Xinyu Li, Kaidie Wang, Yujiao Zou, Quanjuan Shi, Ya Yang, Qingyun Zhao, Wei Zou.
      Autophagy is increasingly recognized as a context-dependent regulatory process that links cellular quality control with systemic metabolic and neurological homeostasis. However, how distinct autophagy pathways contribute to disease progression, and how they are dynamically modulated by host-microbiota interactions, remain incompletely understood. In this review, we synthesize recent advances in the molecular regulation of macroautophagy, microautophagy, and chaperone-mediated autophagy (CMA), with a particular emphasis on selective autophagy and its disease-specific functions. We examine emerging evidence implicating autophagy as a bidirectional modulator in neurodegenerative and metabolic disorders, highlighting conditions under which autophagy exerts protective versus maladaptive effects. Importantly, we integrate recent findings on the microbiota-gut-brain axis to illustrate how microbial signals reshape autophagic responses and influence disease susceptibility and progression. Finally, we summarize current progress and limitations in autophagy-targeted therapeutic strategies, including nanomedicine-based delivery systems, and propose conceptual frameworks to guide the development of precise, context-aware autophagy interventions. This review provides an updated and integrative perspective that bridges molecular mechanisms, host-microbiota crosstalk, and translational opportunities in autophagy-related diseases.
    Keywords:  autophagy; metabolic disorders; microbiota–gut–brain axis; molecular mechanisms; neurodegenerative diseases; therapeutic strategies
    DOI:  https://doi.org/10.3390/cimb48030285
  19. Acta Crystallogr D Struct Biol. 2026 Apr 01.
    Crystal structures of Fsc1, a novel autophagy factor that mediates autophagosome-vacuole fusion in fission yeast.
    Chidiogo Azuka, Jian Liu, Xiangshu Jin.
      Fsc1 is a recently identified autophagy factor in the fission yeast Schizosaccharomyces pombe that is implicated in the autophagosome-vacuole fusion step during the final stages of autophagy. Despite its critical role, the structural basis of Fsc1 function has remained unknown. Here, we report the first crystal structures of the luminal domain of Fsc1, revealing an elongated, modular architecture composed of five tandem fasciclin (FAS1) domains. Each domain adopts a hallmark β-sandwich fold, and the overall assembly forms a continuous scaffold featuring a conserved surface groove within the FAS1-4 domain. Structural and biochemical analyses demonstrate that Fsc1 forms a homodimer in solution through a shared interface observed in two independent crystal forms, supporting a biologically relevant but potentially low-affinity association. Comparative sequence and structural analyses reveal significant homology between Fsc1 and human fasciclin proteins, including TGFBI and periostin, suggesting similar structural principles underlying their functions. Together, these findings provide the first structural insights into Fsc1 and establish a structural framework for understanding how its modular architecture and context-dependent dimerization may facilitate late-stage membrane fusion during autophagy.
    Keywords:  Fsc1; autophagosome–vacuole fusion; autophagy; fasciclin domain
    DOI:  https://doi.org/10.1107/S205979832600197X
  20. PLoS Genet. 2026 Mar 24. 22(3): e1012094
    mTOR signaling regulates demand-adapted hematopoiesis and metabolic reprogramming required for an effective cellular immune response in Drosophila melanogaster larvae.
    Ines Anderl, Jens-Ola Ekström, Tea Tuomela, Mika Rämet, Tiina Susanna Salminen, Laura Vesala.
      The evolutionarily conserved mechanistic Target of Rapamycin (mTOR) pathway connects energy and nutrient availability to growth, proliferation, differentiation, immunity and survival. Here, we investigated the role of the mTOR pathway in Drosophila hematopoiesis and immunity using genetic and transcriptomic analyses of peripheral larval blood cells (hemocytes). We show that blood cell-directed mTor expression induced lamellocyte differentiation as seen after parasitoid wasp infection. Genetic epistasis revealed that lamellocyte hematopoiesis downstream of mTor is mediated by the JNK and p38 pathways. Transcriptomic profiling showed largely similar changes in gene expression patterns of wasp infected and mTor overexpressing hemocytes. While mTOR signaling is necessary for proper lamellocyte differentiation, mTOR Complex 1 (mTORC1) activity is suppressed in mature lamellocytes. Our transcriptome data indicated that hemocyte activation is accompanied by a shift in metabolism towards aerobic glycolysis for energy production, the oxidative pentose phosphate pathway for NADPH recycling, ROS production and detoxification as well as glutaminolysis for glutathione production. Our data highlight the key role of mTOR in controlling blood cell fate in Drosophila.
    DOI:  https://doi.org/10.1371/journal.pgen.1012094
  21. Neuron. 2026 Mar 25. pii: S0896-6273(26)00089-9. [Epub ahead of print]
    Lysosomal salvage of neuronal lipids enables glial infiltration of synaptic regions.
    Emma K Theisen, Irma Magaly Rivas-Serna, Peiwen Cheng, Ryan J Lee, Connon I Thomas, Anza Darehshouri, Taylor R Jay, Govind Kunduri, Tasha T Nguyen, Vera Mazurak, M Thomas Clandinin, Thomas R Clandinin, John P Vaughen.
      The complex morphologies of neurons and glia emerge through profound changes in membrane lipids and proteins during development. Lysosomes are central regulators of membrane remodeling, and mutations that affect lipid turnover in lysosomes are frequently associated with neurological disease. However, how these lysosomal functions might shape brain development remains incompletely understood. By analyzing lipid levels in the Drosophila brain, we discover transient increases in specific sphingolipids during development. This lipid bolus reflects biosynthetic inputs from both neurons and glia, and requires lysosomal catabolism for mature neuronal physiology to emerge. Remarkably, sphingolipid catabolism in glia is substantially driven by the phagolysosomal salvage of neuronal membranes to produce very long-chain ceramide phosphoethanolamine (CPE) lipids. CPE lipids are cell-autonomously required for glial autophagy and ramification into synaptic regions, and a genetic CPE biosensor localizes to infiltrated glial processes. Thus, developmentally regulated lysosomal activity obligately couples neuron-glia metabolic interactions to program dynamic glial morphogenesis.
    Keywords:  GBA; LSDs; VLCFAs; arborization; autophagy; ceramide phosphoethanolamine; glia; glucocerebrosidase; lysosomal storage diseases; neurodevelopment; phagocytosis; sphingolipids; very long chain fatty acids
    DOI:  https://doi.org/10.1016/j.neuron.2026.02.006
  22. PLoS One. 2026 ;21(3): e0345575
    Cell-intrinsic mTOR/LET-363 influences morphological aging of the ALM touch receptor neuron in Caenorhabditis elegans.
    Sophia C Whitley, Ruiling Zhong, Sophie Baumberger, Claire E Richardson.
      The mechanistic target of rapamycin (mTOR) promotes neuronal aging, but it remains unclear whether these effects arise from mTOR activity within neurons, other brain cell types, or peripheral tissues. Here, we tested the hypothesis that Caenorhabditis elegans mTOR/let-363 functions cell-intrinsically in neurons during adulthood to promote age-related neuron morphological aging. We used a floxed let-363 allele in combination with heat-shock-induced, pan-somatic Cre recombinase expression to generate pan-somatic, adult knockdown, and with a Cre-driver that expresses in a small subset of neurons, the Touch Receptor Neurons, to generate neuron-intrinsic knockdown. Adult-onset, pan-somatic knockdown of let-363 did not robustly alter lifespan or neuron morphological aging. In contrast, neuron-specific let-363 knockdown resulted in a reduction in one aspect of neuron morphological aging - ectopic neurite sprouting from the soma - without extending lifespan. Together, these findings suggest that mTOR/let-363 can act cell-intrinsically within neurons to promote or potentiate an aspect of morphological aging. These results help clarify the potential cell-type specificity of mTOR's roles in neuronal aging and provide a foundation for defining the mechanisms through which mTOR intersects with neuron-intrinsic aging pathways.
    DOI:  https://doi.org/10.1371/journal.pone.0345575
  23. bioRxiv. 2026 Mar 16. pii: 2026.03.13.711689. [Epub ahead of print]
    Survey of the human proteostasis network: the ubiquitin-proteasome system.
    Suzanne Elsasser, Evan T Powers, Thomas Stoeger, Xiaojing Sui, Roy D Kurtzbard, Patricia Martínez-Botía, Margaret A Wangeline, Alejandro Rodriguez Gama, Edward L Huttlin, Lisa P Elia, Jeffery W Kelly, Jason E Gestwicki, Judith Frydman, Steven Finkbeiner, Eugenia M Clerico, Richard I Morimoto, Miguel A Prado, Alfred C O Vertegaal, Kay Hofmann, Daniel Finley.
      Modification by ubiquitination governs the half-lives of thousands of proteins that are fated for elimination by either the proteasome or autophagy pathways, depending on the intricate architectures of ubiquitin modification. This system mediates quality control for individual proteins, protein complexes, and organelles, as well as myriad purely regulatory functions. Here we provide a comprehensive survey of the ubiquitin-proteasome system (UPS), the scope of which is at present poorly defined. The UPS, with the inclusion of pathways involving ubiquitin-like modifiers, comprises in our estimate over 1400 distinct proteins in humans, a vast set of activities whose collective impact on the biology of the cell is pervasive. The UPS is an integral component of the proteostasis network (PN), the remainder of which we have also surveyed in recent studies. With the addition of molecular chaperones, proteins from autophagy-lysosome pathway, and related activities, the PN includes in total over 3100 components by our estimates. Comprehensive and systematic definition of these pathways should support a range of ongoing investigations in the areas of genomics, proteomics, biochemistry, cell biology, and disease research.
    DOI:  https://doi.org/10.64898/2026.03.13.711689
  24. bioRxiv. 2026 Mar 17. pii: 2026.03.14.711071. [Epub ahead of print]
    ULK1 drives NDP52-mediated selective autophagic degradation of MHC-I to promote immune evasion in HPV-positive head and neck cancer.
    Lexi Vu, Nicholas S Giacobbi, Mohamed I Khalil, Canchai Yang, William J Eckerman, Evelyn Gomez Recinos, Johnathon D Garber, Hyomin Son, Prerna Chahal, Dara M Villa, Tasha Srivastava, Abigail Z Bennett, Katie R Martin, Craig C Welbon, Caitlin Williamson, William C Spanos, Jeffrey P MacKeigan, Andrew J Olive, Dohun Pyeon.
      Antigen presentation by major histocompatibility complex class I (MHC-I) is critical for tumor cell killing by CD8 + T cells. Accordingly, tumor cells downregulate MHC-I expression through multiple mechanisms, thereby evading the immune response. Importantly, lower levels of MHC-I are associated with poor responses to immune checkpoint inhibitor therapy. Our recent study has shown that the human papillomavirus (HPV) oncoproteins induce MHC-I protein ubiquitination by membrane-associated Ring-CH-type finger 8 (MARCHF8) in HPV-positive head and neck cancer (HPV+ HNC). However, the mechanism by which ubiquitinated MHC-I is degraded remains elusive. By performing genome-wide CRISPR screens, we identified components of the ULK1 and PIK3C3 complexes for autophagy initiation complexes among the top negative regulators of cell-surface MHC-I expression in HPV+ HNC cells. We show that MHC-I is recruited from the ER to autophagosomes by the cargo receptor NDP52, decreasing MHC-I levels. Further, inhibiting the initiation or nucleation steps of autophagy before autophagosome formation is critical for restoring MHC-I levels on the cell surface. Finally, genetic inhibition of autophagy initiation suppresses HPV+ HNC tumor growth in vivo and enhances the CD8 + T cell-mediated antitumor response. Our findings suggest that autophagic degradation of MARCHF8-ubiquitinated MHC-I is a key immune evasion mechanism in HPV+ HNC.
    DOI:  https://doi.org/10.64898/2026.03.14.711071
  25. iScience. 2026 Mar 20. 29(3): 114949
    Cyclin C promotes pancreatic developmentand suppresses cancer initiation by maintenance of the autophagy-lysosome pathway.
    Sara E Hanley, Kathy Q Cai, Stephen D Willis, David C Stieg, Andres J Klein-Szanto, Kerry S Campbell, Randy Strich.
      Cyclin C (CCNC) is a component of the mediator complex that regulates gene transcription. In stressed cells, cyclin C also translocates to the mitochondria to induce fission and stimulate programmed cell death. The present study found that cyclin C is required for autophagy lysosome pathway gene transcription in mouse embryonic fibroblasts. In vivo, pancreatic ablation of Ccnc caused islet atrophy and acinar cell damage. However, Ccnc pancreatic ablation caused more dramatic phenotypes than autophagy mutants alone, including increased mortality and accelerated precancerous lesion formation. Previous studies found that autophagy-deficient pancreatic cells expressing oncogenic Kras undergo Tp53-dependent cell death. However, Kras G12D ;Ccnc -/- pancreata did not undergo cell death, suggesting a role for the mitochondrial cyclin C function. Finally, loss of CCNC activity rendered cells hypersensitive to proteasome inhibitors. These findings identify multiple roles for cyclin C in promoting pancreatic health and suggest a new strategy to target pancreatic neoplasms by inhibiting proteasome function.
    Keywords:  biological sciences; cancer; cell biology
    DOI:  https://doi.org/10.1016/j.isci.2026.114949
  26. FEBS J. 2026 Mar 17.
    Optineurin calibrates STING-mediated type I interferon response.
    Sreeram Kaveti, Nishant Jain.
      Cyclic GMP-AMP synthase (cGAS) senses cytosolic self and microbial DNA to produce cyclic guanosine monophosphate-adenosine monophosphate (cGAMP), a secondary messenger that activates the endoplasmic reticulum-resident transmembrane protein, stimulator of interferon genes (STING). After binding to cGAMP, STING undergoes oligomerisation, exits the endoplasmic reticulum (ER), recruits tank-binding kinase 1 (TBK1) and interferon regulatory factor 3 (IRF3) on Golgi membranes, resulting in the activation of type I interferons (IFNs). STING is found to be a preformed dimer in the ER; however, it is yet unknown whether protein-protein interactions maintain STING in its resting state. Optineurin (OPTN) functions as an adaptor or a scaffold to coordinate autophagy, type I IFN response, vesicle trafficking, and mitophagy. TBK1 commonly binds OPTN and STING to activate type I IFNs in response to extracellular and intracellular cues. However, it remains unclear whether OPTN participates in STING-mediated type I interferon (IFN) response. As STING initiates inflammatory signalling and OPTN functions as an adaptor protein, we asked if OPTN is necessary for STING to mediate type I IFN response. To answer this question, we examined STING-mediated type I IFN response in human and mouse cells depleted of OPTN and elucidated STING-OPTN binding. We found that modulating OPTN levels alters STING-mediated type I IFN response. Further, the N-terminal domain of STING binds to the C-terminal ubiquitin-binding domain of OPTN. In addition, we found that OPTN engages with STING and TBK1. Thus, we conclude that OPTN calibrates STING-mediated type I IFN response. Based on our observations, approaches that include developing tailored molecular glue-like compounds binding STING-OPTN, and determining STING activation might be valuable avenues for understanding and treating autoimmune diseases.
    Keywords:  STING; TBK1; diABZI; optineurin; pSTING‐S‐366; type I IFN response
    DOI:  https://doi.org/10.1111/febs.70490
  27. Cells. 2026 Mar 15. pii: 522. [Epub ahead of print]15(6):
    The Effect of Mechanical Loading on Mitophagy in Aged Myoblasts.
    Evangelos Tolis, Eirini Chatzinikita, Athanasios Moustogiannis, Antonios Giannopoulos, Maria Maridaki, Michael Koutsilieris, Anastassios Philippou.
      Background: During aging, skeletal muscle mass constantly diminishes and myogenic potential declines. At the cellular level, a decline in mitochondrial function is a hallmark of the aging process and the deficiency of the mitochondrial network contributes to a progressive reduction in muscle mass. Autophagic clearance of mitochondria through the process of mitophagy is required to remove impaired or damaged mitochondria, while mitophagy is a key regulator of muscle maintenance. Dysfunctional degradation of mitochondria is increasingly associated with aging (mitophaging), while mechanical stimuli have been shown to ameliorate the aging-induced impaired muscle mass and function; however, less is known about the potential effects of mechanical loading on mitophaging. The aim of the present study was to investigate the effect of mechanical stretching on mitophagy in aged myoblasts, in vitro. Methods: Cell senescence was replicated using a multiple cell division model of C2C12 myoblasts. The control and aged cells were cultured on elastic membranes and underwent passive stretching using a mechanical loading protocol of 15% elongation for 12 h at a frequency of 1 Hz. Cell signaling and gene expression responses of mitophagy-associated and myogenic regulatory factors (MRFs) were assessed through immunoblotting and qRT-PCR of the cell lysates derived from stretched and non-stretched control and aged myoblasts. Results: Mitophagy factor AMP-activated protein kinase (AMPK), mitochondrial biogenesis stimulator peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1a), and mitophagy/mitochondrial biogenesis factor Parkin were downregulated in control stretched myoblasts compared to non-stretched cells, while the specific mechanical loading protocol used also reduced the phosphorylation of unc-51-like autophagy-activating kinase 1 (p-ULK1) (p < 0.05), as well as the expression of myogenic factor 5 (Myf5) and myogenic factor 4 (myogenin) (p < 0.001). Interestingly, this mechanical loading resulted in increased PGC-1a and Parkin expression (p < 0.05) and induced the previously undetected BCL2 interacting protein 3-like (BNIP3L/NIX) and AMPK expression and p-ULK1 activation in the aged myoblasts. In addition, mechanical stretching differentially affected the expression of MRFs in aged cells, upregulating the early differentiation factor, Myf5 (p < 0.01), while downregulating the late differentiation factor myogenin (p < 0.001). Conclusions: These findings suggest the beneficial effects of mechanical loading on the impaired mitophagy and early differentiation in aged myoblasts, as indicated by the mitophagy initiation and the promotion of mitochondrial biogenesis in these cells. The mechanical loading-induced downregulation of mitophagy and myogenesis in the control myoblasts might indicate their loading-specific differential responses compared to the aged cells.
    Keywords:  mechanical loading; mitophagy; senescence
    DOI:  https://doi.org/10.3390/cells15060522
  28. bioRxiv. 2026 Mar 18. pii: 2026.03.16.710895. [Epub ahead of print]
    Cardiac REDD1 alters glucose and fatty acid metabolic gene expression via an mTORC1-independent, PPARα-dependent mechanism and drives hypertrophic growth.
    Mason Wheeler, Jamie Renick, Roslyn Fawbush, Emily McAlpin, Shaunaci Stevens, Karthi Sreedevi, Junco Warren, Michael Dennis, Jessica Pfleger.
       Background: Regulated in development and DNA damage 1 (REDD1) is a highly inducible molecule that plays a role in numerous physiological and pathophysiological processes. It is a well-established negative regulator of mammalian target of rapamycin complex 1 (mTORC1), which is critical for maintaining elevated fatty acid-to-glucose oxidation ratio in the heart. In addition, REDD1 deletion results in hyperglycemia, suggesting that REDD1 is critical for tissue glucose metabolism. The role of REDD1 in regulating cardiac glucose and/or fatty acid metabolism in response to physiologic or pathophysiologic cues, however, remains unexplored.
    Methods: Herein, we utilize AC16 cardiomyocytes with REDD1 deletion, as well as mice with global or cardiomyocyte-specific deletion of Redd1 , and their respective controls. We also subject these mice cardiac pressure overload using transverse aortic constriction (TAC) for 2 weeks or sham operation as a control. To examine the molecular regulators of glucose oxidation, we utilized qPCR and western blotting to evaluate pyruvate dehydrogenase (PDH) kinase ( PDK ) and phospho-PDH (pPDH) levels, respectively. We also directly measured PDH activity and glucose-driven cellular respiration. To investigate the complete REDD1-dependent transcriptome and metabolome, we performed RNA-sequencing (RNA-Seq) and untargeted metabolomics, respectively. To determine if the observed gene expression changes were dependent upon transcription factor peroxisome proliferator-activated receptor alpha (PPARα), we utilized an established pharmacologic PPARα inhibitor, GW6471. Here, we measured PPARα activity directly, as well as the expression of its target genes. In order to determine if our observed effects were mTORC1-dependent, we utilized mTORC1-specific inhibitor, everolimus. Finally, we measured cardiac hypertrophy using gravimetric analyses (heart weight (HW)-to-body weight (BW) or HW-to-tibia length (TL) ratios) and histological analyses of cardiomyocyte cross sectional area (CSA). We also measured mRNA and protein levels of pathological hypertrophic markers Natriuretic Peptide B ( Nppb) and Cardiac Ankyrin Repeat Protein (CARP), respectively.
    Results: Our data demonstrate that physiological levels of glucose induce REDD1 expression in cardiomyocytes. Further, we show that in cardiomyocytes or the hearts of mice with REDD1 deletion, there is elevated PDK4 expression, as well as increased levels of pPDH (S300 and/or S293) and reduced PDH activity. Interestingly, everolimus treatment has no effect on these alterations. In vitro , we also observe elevated glycolysis and glycolytic capacity, and reduced maximal respiratory capacity (MRC) in the presence of glucose. Interestingly, our RNA-Seq data reveals the upregulation of genes involved in fatty acid catabolism. Further, we demonstrate that PPARα activity is enhanced, and everolimus treatment also has no effect on this parameter. Additionally, we show that treatment of cardiomyocytes with GW6471 normalizes the expression of its target genes ( PDK4 , ACSL1 ) and levels of pPDH (S300), that are elevated in cells with REDD1 deletion. Finally, we observe elevated REDD1 in the hearts of mice following TAC. Moreover, we show reduced HW/BW, HW/TL, cardiomyocyte CSA, and levels of cardiac Nppb and CARP in mice with cardiomyocyte Redd1 deletion subjected to TAC versus controls also subjected to TAC. Importantly, TAC-induced reductions in cardiac Pdk4 and pPDH (S293 and S300), are normalized to control levels in mice with Redd1 deletion subjected to TAC.
    Conclusions: Together, our findings suggest that physiological glucose-induced and pathological pressure overload-induced REDD1 is required for enhancing glucose oxidation and suppressing fatty acid oxidation in cardiomyocytes. In this way, REDD1 supports cardiac hypertrophic growth. We also outline a mechanism whereby REDD1 inhibits PPARα activity, thereby inhibiting the expression of its target genes, including PDK4 and those involved in fatty acid oxidation. Finally, we demonstrate that these effects are independent of REDD1's ability to inhibit mTORC1.
    DOI:  https://doi.org/10.64898/2026.03.16.710895
  29. Exp Gerontol. 2026 Mar 19. pii: S0531-5565(26)00083-5. [Epub ahead of print]217 113105
    Mammalian target of rapamycin in chronic liver disease and the potential for therapeutic manipulation.
    Pramudi Wijayasiri, Mamatha Bhat, Aloysious D Aravinthan.
      Chronic Liver Disease (CLD) represents a growing epidemic in the Western world, yet treatment options that effectively slow its progression remain limited. Mammalian target of rapamycin (mTOR) inhibitors, such as sirolimus (also known as rapamycin), have been proposed as potential antifibrotic agents over the past decade; however, their role in chronic liver disease remains underexplored. mTOR is a protein kinase integral to a key cellular pathway, which is essential for normal liver physiology but is also implicated in the pathogenesis of CLD and hepatocellular carcinoma (HCC). This narrative review summarises the role of mTOR in the healthy liver, its dysregulation across common aetiologies of CLD, and its role in HCC. An electronic literature search of Ovid MEDLINE was conducted from database inception to 2025 to identify studies evaluating the role of MTOR in CLD. The review underscores a clear unmet need for well-designed human clinical trials to specifically assess mTOR inhibitors as potential anti-fibrotic therapies.
    Keywords:  Chronic liver disease; Fibrosis; Hepatocellular carcinoma; MTOR; Mammalian target of rapamycin; Sirolimus
    DOI:  https://doi.org/10.1016/j.exger.2026.113105
  30. Curr Biol. 2026 Mar 23. pii: S0960-9822(26)00166-1. [Epub ahead of print]36(6): R259-R261
    Cell biology: Killing the prisoner escaping from mitochondria.
    Arun Kumar Kondadi, Andreas S Reichert.
      Mitochondria contain their own DNA (mtDNA), which can be released via multiple routes and cause inflammation and disease. A recent study revealed the unexpected role of a mitochondrial nuclease, present in the intermembrane space, in preventing mtDNA escape via mitophagy.
    DOI:  https://doi.org/10.1016/j.cub.2026.02.016
  31. Int J Mol Med. 2026 Jun;pii: 142. [Epub ahead of print]57(6):
    Crosstalk between autophagy and ferroptosis in liver diseases (Review).
    Yanming Wei, Kun Zhou, Yuerui Su, Zhihua Luan, Pengcheng Li, Yinxia Chang, Bo Han, Huifang Li, Yuanbiao Qiao, Jinhong Ren.
      Ferroptosis is a novel form of regulated cell death triggered by iron‑dependent accumulation in lipid peroxidation. Multiple intracellular catabolic processes and signaling pathways are implicated in ferroptosis regulation. One is autophagy, which delivers cytoplasmic materials to lysosomes for degradation and is critical for the preservation of cellular homeostasis. The discovered role of autophagy in driving ferroptosis have motivated further explorations of the functional interactions and signal pathways between ferroptosis and autophagy, particularly their crosstalk in the pathogenesis or treatment for various liver diseases, such as drug‑induced liver injury, toxin‑induced liver injury, liver fibrosis and hepatocellular carcinoma. The present review presented an in‑depth overview of research on the crosstalk between autophagy and ferroptosis in diverse liver diseases, including the ones aforementioned. The diverse regulatory mechanisms involved in this process are also analyzed to open a new perspective on the interpretation of liver diseases manifestations and provide potential targets for drug discovery and effective intervene.
    Keywords:  autophagy; crosstalk; drug‑induced liver injury; ferroptosis; hepatocellular carcinoma; liver fibrosis; toxin‑induced liver injury
    DOI:  https://doi.org/10.3892/ijmm.2026.5813
  32. Trends Cell Biol. 2026 Mar 25. pii: S0962-8924(26)00033-4. [Epub ahead of print]
    Repair condensates and lipid domains in lysosome integrity.
    Claudio Bussi, Weiping Li.
      Lysosomes are sophisticated signaling hubs whose function depends on membrane integrity. A breach of this barrier, known as lysosomal membrane permeabilization, triggers inflammation and cell death, driving pathologies from lysosomal storage disorders to neurodegeneration. Cells counter membrane damage with diverse repair mechanisms, including endosomal sorting complexes required for transport machinery, sphingomyelin scrambling, annexin-mediated scaffolding, lipid transport, and stress granule plugging. This diversity suggests singular strategies are insufficient, posing an 'orchestration challenge' regarding precise initiation, spatial organization, and temporal coordination. This opinion article proposes that biomolecular condensation, initiated by damage cues, acts as a primary organizing principle. We suggest lysosomal injury nucleates de novo 'repair condensates' that stabilize compromised membranes and serve as recruitment and organizational hubs for repair machinery.
    Keywords:  biomolecular condensates; lipids; lysophagy; lysosomes; membrane damage
    DOI:  https://doi.org/10.1016/j.tcb.2026.03.002
  33. Antioxid Redox Signal. 2026 Apr;44(10-12): 528-549
    Activation of Mitophagy by Kinetin Mitigates Coal-Silica Mixed Dust-Induced Pulmonary Fibrosis via Modulating Macrophage Mitochondrial Function in Mice.
    Meiyu Chang, Qiang Zhou, Yi Guan, Yingzheng Zhao, Shuhan Guo, Qiufang Qu, Le Liu, Zhiheng Li, Xiangwei Zhao, Hong Cao, Sanqiao Yao.
       AIMS: Coal workers' pneumoconiosis (CWP) is an occupational lung disease caused by the inhalation of coal dust. A key underlying pathogenic mechanism is driven by mitochondrial dysfunction and excessive reactive oxygen species (ROS), which trigger macrophage inflammation and cell death. Damaged mitochondria are selectively degraded via mitophagy, a process essential for maintaining mitochondrial homeostasis and promoting cell survival. However, the role of mitophagy dysregulation in dust-induced mitochondrial dysfunction and the underlying treatment with kinetin remain unclear. This study aimed to explore the role of PINK1/Parkin-mediated mitophagy in coal-silica mixed dust (CSD)-induced mitochondrial damage and to investigate the therapeutic potential of kinetin in targeting this pathway.
    RESULTS: In this study, we compared the effects of CSD exposure and kinetin treatment on mitophagy, mitochondrial function, inflammation, and pulmonary fibrosis. We found that CSD exposure triggered ROS accumulation, mitochondrial membrane potential collapse, and impaired oxidative phosphorylation, leading to reduced adenosine triphosphate synthesis. Mechanistically, CSD suppressed PINK1/Parkin signaling and diminished LC3B mitochondrial recruitment, resulting in defective mitophagy. Notably, kinetin treatment and PINK1 overexpression restored PINK1/Parkin activation and LC3II-dependent mitophagy, alleviated mitochondrial dysfunction, and suppressed subsequent macrophage inflammation and pulmonary fibrosis. Genetic knockdown of PINK1 abolished the protective effects of kinetin, confirming a PINK1-dependent mechanism.
    INNOVATION: Our results revealed that kinetin is a PINK1-dependent mitophagy activator, positioning it as a promising therapeutic candidate for CWP by targeting mitochondrial integrity.
    CONCLUSION: Kinetin exerts its antifibrotic effects on CWP by promoting PINK1-mediated mitophagy, improving mitochondrial function, and alleviating macrophage inflammation. Antioxid. Redox Signal. 44, 528-549.
    Keywords:  coal–silica mixed dust; inflammation; kinetin; mitochondrial function; mitophagy; pulmonary fibrosis
    DOI:  https://doi.org/10.1177/15230864251411565
  34. Nat Commun. 2026 Mar 23.
    RFC4 drives temozolomide resistance in glioblastoma by activating STK38-BECN1-dependent autophagy.
    Min Mao, Hang Ji, Wen-Qian Yu, Qu-Jing Gai, Qiang Sun, Qian Yan, Sen-Lin Xu, Meng-Li Zhu, Mei-Hua Qu, Han-Min Liu, Jean-Philipe Hugnot, Xi He, Xin Wang, Yan Wang.
      Glioblastoma (GBM) remains a lethal brain tumor due to therapy resistance. While autophagy contributes to temozolomide (TMZ) resistance, its regulation is incompletely understood. This study investigates the role of replication factor RFC4, which is associated with poor prognosis and TMZ resistance in GBM. Multi-omics analyses and molecular experiments reveal that TMZ-induced chromatin accessibility enables transcription factor YY1 to bind the RFC4 promoter and upregulate its expression. RFC4, in turn, stabilizes the kinase STK38, which is essential for autophagosome formation. The RFC4-STK38 interaction facilitates BECN1 recruitment, thereby activating autophagy. Phosphorylation of STK38 at T444 stabilizes this complex, whereas a phospho-deficient mutant impairs autophagy. In vivo, RFC4 overexpression confers TMZ resistance, reversible by autophagy inhibition. Thus, our findings identify the RFC4-STK38-BECN1 axis as a mechanism underlying TMZ resistance and a potential target for precision therapy in GBM.
    DOI:  https://doi.org/10.1038/s41467-026-70798-1
  35. Proc Natl Acad Sci U S A. 2026 Mar 31. 123(13): e2602991123
    VAMP8 function reveals tight linkage between endocytic recycling and endocytosis.
    Ailing Liu, Yueping Li, Zheng Huang, Wen Chen, Peiliu Xu, Xiangying Wei, Guosheng Hu, Shuangquan Liu, Xiaoxia Liu, Yaohui He, Danling Wang, Sandra L Schmid, Zhiming Chen.
      Clathrin-mediated endocytosis (CME) is a multistage process that involves the initiation and stabilization of clathrin-coated pits (CCPs) that invaginate and finally detach from the plasma membrane to form clathrin-coated vesicles (CCVs). Given that Soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) proteins are essential for downstream vesicle targeting and fusion events, their recruitment into nascent CCVs has been suggested to be a prerequisite for CME progression. However, which and how SNARE proteins regulate CME remains to be explored. Here, we showed that siRNA-mediated knockdown of the R-SNARE, vesicle-associated membrane protein 8 (VAMP8) impairs CCP initiation, stabilization, and invagination and strongly inhibits CME. Mechanistically, recruitment of VAMP8 to CCVs is not required for CME. Instead, depletion of VAMP8 inhibits recycling of endocytic cargoes and as exemplified here by transferrin receptor, skews their trafficking toward lysosomal degradation. VAMP8 depletion therefore indirectly impairs CCV formation and inhibits CME by depleting endocytic cargo. Overall, our study provides insights into the crosstalk between endocytosis and endocytic recycling of CME cargo and demonstrates the critical role for cargo recruitment in stabilizing nascent CCPs to regulate CME.
    Keywords:  SNARE; clathrin; endocytosis; recycling
    DOI:  https://doi.org/10.1073/pnas.2602991123
  36. Biochem J. 2026 Mar 20. pii: BCJ20250342. [Epub ahead of print]
    Binding of 14-3-3 stabilises recombinant AMPKγ2-containing complexes.
    David Carling, Shu-Yang Chen, Jane Bennett, Naveenan Navaratnam, Rebeca Fiadeiro, Angela Woods, Alex Montoya, Pavel Shliaha, Simone Kunzelmann, Steven A Howell, Shahid Mehmood, Andrew G Purkiss, Jon R Wilson, Steven J Gamblin.
      AMP-activated protein kinase (AMPK) plays an important role in maintaining energy homeostasis in mammals. AMPK is heterotrimer of an α catalytic subunit, and two regulatory subunits, β and γ. In mammals, each subunit has different isoforms (α1/α2, β1/β2, and γ1/γ2/γ3) encoded by separate genes leading to the potential expression of 12 AMPK complexes. Here we show that AMPK containing the long forms of γ2 (γ2a, encoding a protein of 569 amino acids, and γ2c, 525 amino acids) bind to 14-3-3. In contrast to AMPK containing the short form of γ2 (γ2b, 328 amino acids), bacterial expression of AMPK containing the long forms of g2 requires co-expression with 14-3-3 and prior phosphorylation of Thr172 within the α subunit. AMPKγ2-14-3-3 complexes have reduced activity compared to AMPKγ1 or AMPKγ2b but retain allosteric activation by AMP and the AMPK activator, 991. We found that two predicted 14-3-3 binding sites within γ2a (T97 and S122) were phosphorylated in the bacterially expressed AMPK complex. Furthermore, we show that a peptide spanning these two phosphorylated sites binds to 14-3-3 in vitro and determined the crystal structure of this 14-3-3-peptide co-complex. These results indicate that 14-3-3 binds to the N-terminal region of γ2a/c, reducing the activity of AMPK relative to AMPKγ1 and AMPKγ2b. Our findings reveal a new mode of regulation of AMPK containing the long forms of γ2. Whilst the biological significance of 14-3-3 binding to AMPKγ2a/c complexes remains to be determined, our studies provide the starting point to begin to address this issue.
    Keywords:  14-3-3 proteins; AMPK; phosphorylation/dephosphorylation
    DOI:  https://doi.org/10.1042/BCJ20250342
  37. Cell Rep. 2026 Mar 24. pii: S2211-1247(26)00255-X. [Epub ahead of print]45(4): 117177
    MAP2K6 directly phosphorylates BCL2L13 to mediate mitophagy for suppressing tumorigenicity.
    Guangsuo Xing, Yile Huang, Xiwen Liu, Linpeng Li, Zichao Liu, Yi Wu, Yanshuang Zhou, Yingzhe Ding, Baodan Chen, Guanru Xue, Zijing Li, Zhihong Hao, Yang Liu, Wenhui Fan, Haolin Ding, Shan Liang, Jingcai He, Junwei Wang, Jian Zhang, Dajiang Qin, Wuming Wang, Gang Lu, Wai-Yee Chan, Pixin Ran, Huaiqiang Ju, Ming Dong, Wenhua Liang, Xingguo Liu, Keshi Chen.
      The mitogen-activated protein kinase (MAPK) pathway widely regulates development and cancer. However, the subcellular localization and function of the secondary kinases in the MAPK pathway remain unclear. Here, we identified mitogen-activated protein kinase kinase 6 or 3 (MKK6/MKK3) as tumor suppressors that could significantly activate mitophagy and suppress tumor growth in lung adenocarcinoma (LUAD). Mechanistically, among MKK1-7, only MKK6/MKK3 exhibited subcellular organellar localization in mitochondria and autophagosome interaction site. The function of MKK6 in mitophagy and tumorigenicity was dependent on its kinase activity, but not through p38. MKK6 directly phosphorylated BCL2L13 at serine 426, enhancing the interaction between BCL2L13 and LC3B, which, in turn, promoted mitophagy, inhibited oxidative phosphorylation (OXPHOS), and prevented tumor growth. Our studies not only revealed that MKK6-BCL2L13 phosphorylation at the interorganellar site can affect mitochondrial quality in tumorigenicity but also might provide a potential therapeutic strategy for LUAD treatment.
    Keywords:  CP: cancer; CP: metabolism; OXPHOS; autophagy; cancer metabolism; metabolism; mitochondria; mitophagy
    DOI:  https://doi.org/10.1016/j.celrep.2026.117177
  38. PLoS Biol. 2026 Mar;24(3): e3003662
    A quantitative cell-based reporter links TDP-43 aggregation and dysfunction to define pathogenic mechanisms.
    Lohany Dias Mamede, Miwei Hu, Jaime Vaquer-Alicea, Amanda R Titus, Patricia M Passos, Erica Lantelme, Rachel L French, Paige A Kirschner, Marc I Diamond, Timothy M Miller, Yuna M Ayala.
      TDP-43 pathology is a hallmark of fatal neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS), frontotemporal dementia (FTD), and limbic-predominant age-related TDP-43-encephalopathy (LATE). In affected patients, cytoplasmic TDP-43 aggregates are accompanied by disruption of its normal nuclear localization and function. Because TDP-43 is an RNA binding protein that controls transcript processing, including repression of cryptic exon splicing, its loss leads to dysregulation of gene expression. Despite its central significance in disease, the connection between TDP-43 aggregation and dysfunction remains poorly understood, and models to study the underlying mechanisms are limited. Here, we characterize a robust and quantitative cell-based reporter that captures both aggregation and the resulting loss of function. Using this human biosensor cell line, we show that aggregation initiated by prion-like seeding drives progressive depletion of nuclear TDP-43 and induces signature features of diminished TDP-43 activity, such as increased DNA damage and activation of cryptic exon splicing. We find that aggregate seeding also induces cryptic exon splicing in human neurons implying that this pathological link extends to disease-relevant models. The seeding model provides a platform for dissecting mechanisms that underlie TDP-43 pathology and for identifying factors that modulate the aggregation-to-dysfunction transition. Our data shows that aggregate seeding impacts TDP-43 autoregulation, initiating a toxic feed-forward mechanism that disrupts TDP-43 homeostasis. Furthermore, reducing ataxin-2 levels decreases aggregation and restores TDP-43 activity. Together, these findings reveal a molecularly guided strategy to directly impact TDP-43 activity by decreasing its misfolding and aggregation, highlighting approaches to prevent TDP-43 dysfunction and mitigate toxicity under pathological conditions.
    DOI:  https://doi.org/10.1371/journal.pbio.3003662
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