bims-mitdis 2024-05-12 papers

bims-mitdis

Biomed News

on Mitochondrial disorders

Issue of 2024–05–12
34 papers selected by
Catalina Vasilescu, Helmholz Munich

Systematic analysis of NDUFAF6 in complex I assembly and mitochondrial disease.
mtDNA-Server 2: advancing mitochondrial DNA analysis through highly parallelized data processing and interactive analytics.
Charcot-Marie-Tooth type 2A in vivo models: Current updates.
A novel pathogenic mitochondrial DNA variant m.4344T>C in tRNAGln causes developmental delay.
The mitochondrial tRNA-derived fragment, mt-tRF-LeuTAA, couples mitochondrial metabolism to insulin secretion.
An interphase actin wave promotes mitochondrial content mixing and organelle homeostasis.
Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management.
High fat diet ameliorates mitochondrial cardiomyopathy in CHCHD10 mutant mice.
Understanding Coenzyme Q.
A novel protein CYTB-187AA encoded by the mitochondrial gene CYTB modulates mammalian early development.
Topical Steroid Withdrawal is a Targetable Excess of Mitochondrial NAD.
Uncharacterized yeast gene YBR238C, an effector of TORC1 signaling in a mitochondrial feedback loop, accelerates cellular aging via HAP4- and RMD9-dependent mechanisms.
The MCU and MCUb amino-terminal domains tightly interact: mechanisms for low conductance assembly of the mitochondrial calcium uniporter complex.
A succinylation switch to maligancy: SUCLG1, mitochondrial transcription and leukemia.
Dendrite architecture determines mitochondrial distribution patterns in vivo.
Mitochondrial diabetes plus phenotypes due to the m.3243A > G variant require correlation with heteroplasmy rates.
Primary mitochondrial disorders and mimics: Insights from a large French cohort.
Major AlphaFold upgrade offers boost for drug discovery.
Newborn Genetic Screening: Significance in Early Diagnosis of an Infant with Mitochondrial DNA Depletion Syndrome-6.
A new mutation in the Parkinson's-related FBXO7 gene impairs mitochondrial and proteasomal function.
How to treat a "sweetheart" in mitochondrial cardiomyopathy.
Lipid droplets and neurodegeneration.
Spatial mapping of hepatic ER and mitochondria architecture reveals zonated remodeling in fasting and obesity.
LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants.
Federated benchmarking of medical artificial intelligence with MedPerf.
A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy.
Establishment of a registry of clinical data and bioresources for rare nervous system diseases.
Giant organelle vesicles to uncover intracellular membrane mechanics and plasticity.
Depleting Cellular Retinoic Acid Binding Protein 1 Impairs UPRmt.
Gene therapy trials deliver double win.
Mitochondria regulate proliferation in adult cardiac myocytes.
Spatial transcriptomics in health and disease.
Innovative methodologies for rare diseases clinical trials.
Enigmatic missense mutations can cause disease via creation of de novo nuclear export signals.

Nat Metab. 2024 May 08.

Systematic analysis of NDUFAF6 in complex I assembly and mitochondrial disease.

Andrew Y Sung, Rachel M Guerra, Laura H Steenberge, Charlotte L Alston, Kei Murayama, Yasushi Okazaki, Masaru Shimura, Holger Prokisch, Daniele Ghezzi, Alessandra Torraco, Rosalba Carrozzo, Agnès Rötig, Robert W Taylor, James L Keck, David J Pagliarini.

Isolated complex I (CI) deficiencies are a major cause of primary mitochondrial disease. A substantial proportion of CI deficiencies are believed to arise from defects in CI assembly factors (CIAFs) that are not part of the CI holoenzyme. The biochemistry of these CIAFs is poorly defined, making their role in CI assembly unclear, and confounding interpretation of potential disease-causing genetic variants. To address these challenges, we devised a deep mutational scanning approach to systematically assess the function of thousands of NDUFAF6 genetic variants. Guided by these data, biochemical analyses and cross-linking mass spectrometry, we discovered that the CIAF NDUFAF6 facilitates incorporation of NDUFS8 into CI and reveal that NDUFS8 overexpression rectifies NDUFAF6 deficiency. Our data further provide experimental support of pathogenicity for seven novel NDUFAF6 variants associated with human pathology and introduce functional evidence for over 5,000 additional variants. Overall, our work defines the molecular function of NDUFAF6 and provides a clinical resource for aiding diagnosis of NDUFAF6-related diseases.

DOI: https://doi.org/10.1038/s42255-024-01039-2
Nucleic Acids Res. 2024 May 06. pii: gkae296. [Epub ahead of print]

mtDNA-Server 2: advancing mitochondrial DNA analysis through highly parallelized data processing and interactive analytics.

Hansi Weissensteiner, Lukas Forer, Florian Kronenberg, Sebastian Schönherr.

Over the past decade, mtDNA-Server established itself as one of the most widely used variant calling web-services for human mitochondrial genomes. The service accepts sequencing data in BAM format and returns an annotated variant analysis report for both homoplasmic and heteroplasmic variants. In this work we present mtDNA-Server 2, which includes several new features highly requested by the community. Most importantly, it includes (a) the integration of a novel variant calling mode that accurately call insertions, deletions and single nucleotide variants at once, (b) the integration of additional quality control and input validation modules, (c) a method to estimate the required coverage to minimize false positives and (d) an interactive analytics dashboard. Furthermore, we migrated the complete analysis workflow to the Nextflow workflow manager for improved parallelization, reproducibility and local execution. Recognizing the importance of insertions and deletions as well as offering novel quality control, validation and reporting features, mtDNA-Server 2 provides researchers and clinicians a new state-of-the-art analysis platform for interpreting mitochondrial genomes. mtDNA-Server 2 is available via mitoverse, our analysis platform that offers a centralized place for mtDNA analysis in the cloud. The web-service, source code and its documentation are freely accessible at https://mitoverse.i-med.ac.at.

DOI: https://doi.org/10.1093/nar/gkae296
J Cell Mol Med. 2024 May;28(9): e18293

Charcot-Marie-Tooth type 2A in vivo models: Current updates.

Elena Abati, Mafalda Rizzuti, Alessia Anastasia, Giacomo Pietro Comi, Stefania Corti, Federica Rizzo.

  Charcot-Marie-Tooth type 2A (CMT2A) is an inherited sensorimotor neuropathy associated with mutations within the Mitofusin 2 (MFN2) gene. These mutations impair normal mitochondrial functioning via different mechanisms, disturbing the equilibrium between mitochondrial fusion and fission, of mitophagy and mitochondrial axonal transport. Although CMT2A disease causes a significant disability, no resolutive treatment for CMT2A patients to date. In this context, reliable experimental models are essential to precisely dissect the molecular mechanisms of disease and to devise effective therapeutic strategies. The most commonly used models are either in vitro or in vivo, and among the latter murine models are by far the most versatile and popular. Here, we critically revised the most relevant literature focused on the experimental models, providing an update on the mammalian models of CMT2A developed to date. We highlighted the different phenotypic, histopathological and molecular characteristics, and their use in translational studies for bringing potential therapies from the bench to the bedside. In addition, we discussed limitations of these models and perspectives for future improvement.

Keywords:  Charcot–Marie‐Tooth type 2A; animal model; mitofusin 2; mouse models

DOI:  https://doi.org/10.1111/jcmm.18293
J Hum Genet. 2024 May 10.

A novel pathogenic mitochondrial DNA variant m.4344T>C in tRNAGln causes developmental delay.

Xiaojie Yin, Qiyu Dong, Shuanglong Fan, Lina Yang, Hao Li, Yijun Jin, Mahlatsi Refiloe Laurentinah, Xiandan Chen, Aliaksei Sysa, Hezhi Fang, Jianxin Lyu, Yongguo Yu, Ya Wang.

Mitochondrial diseases are a group of genetic diseases caused by mutations in mitochondrial DNA and nuclear DNA. However, the genetic spectrum of this disease is not yet complete. In this study, we identified a novel variant m.4344T>C in mitochondrial tRNAGln from a patient with developmental delay. The mutant loads of m.4344T>C were 95% and 89% in the patient's blood and oral epithelial cells, respectively. Multialignment analysis showed high evolutionary conservation of this nucleotide. TrRosettaRNA predicted that m.4344T>C variant would introduce an additional hydrogen bond and alter the conformation of the T-loop. The transmitochondrial cybrid-based study demonstrated that m.4344T>C variant impaired the steady-state level of mitochondrial tRNAGln and decreased the contents of mitochondrial OXPHOS complexes I, III, and IV, resulting in defective mitochondrial respiration, elevated mitochondrial ROS production, reduced mitochondrial membrane potential and decreased mitochondrial ATP levels. Altogether, this is the first report in patient carrying the m.4344T>C variant. Our data uncover the pathogenesis of the m.4344T>C variant and expand the genetic mutation spectrum of mitochondrial diseases, thus contributing to the clinical diagnosis of mitochondrial tRNAGln gene variants-associated mitochondrial diseases.

DOI: https://doi.org/10.1038/s10038-024-01254-5
Mol Metab. 2024 May 03. pii: S2212-8778(24)00086-3. [Epub ahead of print] 101955

The mitochondrial tRNA-derived fragment, mt-tRF-LeuTAA, couples mitochondrial metabolism to insulin secretion.

Cecile Jacovetti, Chris Donnelly, Véronique Menoud, Mara Suleiman, Cristina Cosentino, Jonathan Sobel, Kejing Wu, Karim Bouzakri, Piero Marchetti, Claudiane Guay, Bengt Kayser, Romano Regazzi.

   OBJECTIVE: The contribution of the mitochondrial electron transfer system to insulin secretion involves more than just energy provision. We identified a small RNA fragment (mt-tRF-LeuTAA) derived from the cleavage of a mitochondrially-encoded tRNA that is conserved between mice and humans. The role of mitochondrially-encoded tRNA-derived fragments remains unknown. This study aimed to characterize the impact of mt-tRF-LeuTAA, on mitochondrial metabolism and pancreatic islet functions.
METHODS: We used antisense oligonucleotides to reduce mt-tRF-LeuTAA levels in primary rat and human islet cells, as well as in insulin-secreting cell lines. We performed a joint transcriptome and proteome analysis upon mt-tRF-LeuTAA inhibition. Additionally, we employed pull-down assays followed by mass spectrometry to identify direct interactors of the fragment. Finally, we characterized the impact of mt-tRF-LeuTAA silencing on the coupling between mitochondrial metabolism and insulin secretion using high-resolution respirometry and insulin secretion assays.
RESULTS: Our study unveils a modulation of mt-tRF-LeuTAA levels in pancreatic islets in different Type 2 diabetes models and in response to changes in nutritional status. The level of the fragment is finely tuned by the mechanistic target of rapamycin complex 1. Located within mitochondria, mt-tRF-LeuTAA interacts with core subunits and assembly factors of respiratory complexes of the electron transfer system. Silencing of mt-tRF-LeuTAA in islet cells limits the inner mitochondrial membrane potential and impairs mitochondrial oxidative phosphorylation, predominantly by affecting the Succinate (via Complex II)-linked electron transfer pathway. Lowering mt-tRF-LeuTAA impairs insulin secretion of rat and human pancreatic β-cells.
CONCLUSIONS: Our findings indicate that mt-tRF-LeuTAA interacts with electron transfer system complexes and is a pivotal regulator of mitochondrial oxidative phosphorylation and its coupling to insulin secretion.

Keywords:  Insulin secretion; Mitochondrial OXPHOS; Mitochondrial tRNA-derived fragments

DOI:  https://doi.org/10.1016/j.molmet.2024.101955
Nat Commun. 2024 May 07. 15(1): 3793

An interphase actin wave promotes mitochondrial content mixing and organelle homeostasis.

Stephen M Coscia, Andrew S Moore, Cameron P Thompson, Christian F Tirrito, E Michael Ostap, Erika L F Holzbaur.

Across the cell cycle, mitochondrial dynamics are regulated by a cycling wave of actin polymerization/depolymerization. In metaphase, this wave induces actin comet tails on mitochondria that propel these organelles to drive spatial mixing, resulting in their equitable inheritance by daughter cells. In contrast, during interphase the cycling actin wave promotes localized mitochondrial fission. Here, we identify the F-actin nucleator/elongator FMNL1 as a positive regulator of the wave. FMNL1-depleted cells exhibit decreased mitochondrial polarization, decreased mitochondrial oxygen consumption, and increased production of reactive oxygen species. Accompanying these changes is a loss of hetero-fusion of wave-fragmented mitochondria. Thus, we propose that the interphase actin wave maintains mitochondrial homeostasis by promoting mitochondrial content mixing. Finally, we investigate the mechanistic basis for the observation that the wave drives mitochondrial motility in metaphase but mitochondrial fission in interphase. Our data indicate that when the force of actin polymerization is resisted by mitochondrial tethering to microtubules, as in interphase, fission results.

DOI: https://doi.org/10.1038/s41467-024-48189-1
Prog Retin Eye Res. 2024 May 03. pii: S1350-9462(24)00029-6. [Epub ahead of print]101 101264

Mitochondrial retinopathies and optic neuropathies: The impact of retinal imaging on modern understanding of pathogenesis, diagnosis, and management.

Enrico Borrelli, Francesco Bandello, Camiel J F Boon, Valerio Carelli, Guy Lenaers, Michele Reibaldi, Srinivas R Sadda, Alfredo A Sadun, David Sarraf, Patrick Yu-Wai-Man, Piero Barboni.

  Advancements in ocular imaging have significantly broadened our comprehension of mitochondrial retinopathies and optic neuropathies by examining the structural and pathological aspects of the retina and optic nerve in these conditions. This article aims to review the prominent imaging characteristics associated with mitochondrial retinopathies and optic neuropathies, aiming to deepen our insight into their pathogenesis and clinical features. Preceding this exploration, the article provides a detailed overview of the crucial genetic and clinical features, which is essential for the proper interpretation of in vivo imaging. More importantly, we will provide a critical analysis on how these imaging modalities could serve as biomarkers for characterization and monitoring, as well as in guiding treatment decisions. However, these imaging methods have limitations, which will be discussed along with potential strategies to mitigate them. Lastly, the article will emphasize the potential advantages and future integration of imaging techniques in evaluating patients with mitochondrial eye disorders, considering the prospects of emerging gene therapies.

Keywords:  Fundus autofluorescence; Imaging; Mitochondria; Optic neuropathy; Optical coherence tomography; Optical coherence tomography angiography; Retinal dystrophy

DOI:  https://doi.org/10.1016/j.preteyeres.2024.101264
EMBO Mol Med. 2024 May 09.

High fat diet ameliorates mitochondrial cardiomyopathy in CHCHD10 mutant mice.

Nneka Southwell, Onorina Manzo, Sandra Bacman, Dazhi Zhao, Nicole M Sayles, Jalia Dash, Keigo Fujita, Marilena D'Aurelio, Annarita Di Lorenzo, Giovanni Manfredi, Hibiki Kawamata.

  Mutations in CHCHD10, a mitochondrial protein with undefined functions, are associated with autosomal dominant mitochondrial diseases. Chchd10 knock-in mice harboring a heterozygous S55L mutation (equivalent to human pathogenic S59L) develop a fatal mitochondrial cardiomyopathy caused by CHCHD10 aggregation and proteotoxic mitochondrial integrated stress response (mtISR). In mutant hearts, mtISR is accompanied by a metabolic rewiring characterized by increased reliance on glycolysis rather than fatty acid oxidation. To counteract this metabolic rewiring, heterozygous S55L mice were subjected to chronic high-fat diet (HFD) to decrease insulin sensitivity and glucose uptake and enhance fatty acid utilization in the heart. HFD ameliorated the ventricular dysfunction of mutant hearts and significantly extended the survival of mutant female mice affected by severe pregnancy-induced cardiomyopathy. Gene expression profiles confirmed that HFD increased fatty acid utilization and ameliorated cardiomyopathy markers. Importantly, HFD also decreased accumulation of aggregated CHCHD10 in the S55L heart, suggesting activation of quality control mechanisms. Overall, our findings indicate that metabolic therapy can be effective in mitochondrial cardiomyopathies associated with proteotoxic stress.

Keywords:  CHCHD10; High-Fat Diet; Mitochondrial Cardiomyopathy; Mitophagy

DOI:  https://doi.org/10.1038/s44321-024-00067-5
Physiol Rev. 2024 May 09.

Understanding Coenzyme Q.

Ying Wang, Noah Lilienfeldt, Siegfried Hekimi.

  Coenzyme Q (CoQ), also known as ubiquinone, comprises a benzoquinone head group and a long isoprenoid sidechain. It is thus extremely hydrophobic and resides in membranes. It is best known for its complex function as an electron transporter in the mitochondrial electron transport chain (ETC) and in several other cellular processes. In fact, CoQ appears to be central to the redox balance of the cell. Remarkably, its structure and properties have not changed from bacteria to vertebrates. In metazoans, it is synthesized in all cells and is found in most, and maybe all, biological membranes. CoQ is also known as a nutritional supplement, mostly because of its involvement with antioxidant defenses. However, whether there is any health benefit from oral consumption of CoQ is not well established. Here we review the function of CoQ as a redox active molecule in the ETC and other enzymatic systems, its role as a pro-oxidant in reactive oxygen species generation, and its separate involvement in antioxidant mechanisms. We also review CoQ biosynthesis, which is particularly complex because of its extreme hydrophobicity, as well as the biological consequences of primary and secondary CoQ deficiency, including in human patients. Primary CoQ deficiency is a rare inborn condition due to mutation in CoQ biosynthetic genes. Secondary CoQ deficiency is much more common as it accompanies a variety of pathological conditions, including mitochondrial disorders as well as aging. In this context, we discuss the importance, but also the great difficulty, of alleviating CoQ deficiency by CoQ supplementation.

Keywords:  CoQ; CoQ deficiency; Coenzyme Q; Mitochondrial disease; Ubiquinone

DOI:  https://doi.org/10.1152/physrev.00040.2023
Cell Metab. 2024 Apr 29. pii: S1550-4131(24)00132-3. [Epub ahead of print]

A novel protein CYTB-187AA encoded by the mitochondrial gene CYTB modulates mammalian early development.

Zhijuan Hu, Liang Yang, Maolei Zhang, Haite Tang, Yile Huang, Yujie Su, Yingzhe Ding, Chong Li, Mengfei Wang, Yunhao Zhou, Qing Zhang, Liman Guo, Yue Wu, Qianqian Wang, Ning Liu, Haoran Kang, Yi Wu, Deyang Yao, Yukun Li, Zifeng Ruan, Hao Wang, Feixiang Bao, Guopan Liu, Junwei Wang, Yaofeng Wang, Wuming Wang, Gang Lu, Dajiang Qin, Duanqing Pei, Wai-Yee Chan, Xingguo Liu.

  The mitochondrial genome transcribes 13 mRNAs coding for well-known proteins essential for oxidative phosphorylation. We demonstrate here that cytochrome b (CYTB), the only mitochondrial-DNA-encoded transcript among complex III, also encodes an unrecognized 187-amino-acid-long protein, CYTB-187AA, using the standard genetic code of cytosolic ribosomes rather than the mitochondrial genetic code. After validating the existence of this mtDNA-encoded protein arising from cytosolic translation (mPACT) using mass spectrometry and antibodies, we show that CYTB-187AA is mainly localized in the mitochondrial matrix and promotes the pluripotent state in primed-to-naive transition by interacting with solute carrier family 25 member 3 (SLC25A3) to modulate ATP production. We further generated a transgenic knockin mouse model of CYTB-187AA silencing and found that reduction of CYTB-187AA impairs females' fertility by decreasing the number of ovarian follicles. For the first time, we uncovered the novel mPACT pattern of a mitochondrial mRNA and demonstrated the physiological function of this 14th protein encoded by mtDNA.

Keywords:  early development; mitochondria; mitochondrial DNA; ovarian follicles; pluripotency; primed-to-naive transition; ribosomes; translation

DOI:  https://doi.org/10.1016/j.cmet.2024.04.012
medRxiv. 2024 Apr 19. pii: 2024.04.17.24305846. [Epub ahead of print]

Topical Steroid Withdrawal is a Targetable Excess of Mitochondrial NAD.

NIAID Centralized Sequencing Program

Background: Topical corticosteroids (TCS) are first-line therapies for numerous skin conditions. Topical Steroid Withdrawal (TSW) is a controversial diagnosis advocated by patients with prolonged TCS exposure who report severe systemic reactions upon treatment cessation. However, to date there have been no systematic clinical or mechanistic studies to distinguish TSW from other eczematous disorders.
Methods: A re-analysis of a previous survey with eczematous skin disease was performed to evaluate potential TSW distinguishing symptoms. We subsequently conducted a pilot study of 16 patients fitting the proposed diagnostic criteria. We then performed: tissue metabolomics, transcriptomics, and immunostaining on skin biopsies; serum metabolomics and cytokine assessments; shotgun metagenomics on microbiome skin swabs; genome sequencing; followed by functional, mechanistic studies using human skin cell lines and mice.
Results: Clinically distinct TSW symptoms included burning, flushing, and thermodysregulation. Metabolomics and transcriptomics both implicated elevated NAD+ oxidation stemming from increased expression of mitochondrial complex I and conversion of tryptophan into kynurenine metabolites. These abnormalities were induced by glucocorticoid exposure both in vitro and in a cohort of healthy controls (N=19) exposed to TCS. Targeting complex I via either metformin or the herbal compound berberine improved outcomes in both cell culture and in an open-label case series for patients with TSW.
Conclusion: Taken together, our results suggest that TSW has a distinct dermatopathology. While future studies are needed to validate these results in larger cohorts, this work provides the first mechanistic evaluation into TSW pathology, and offers insights into clinical identification, pharmacogenomic candidates, and directed therapeutic strategies.

DOI: https://doi.org/10.1101/2024.04.17.24305846
Elife. 2024 May 07. pii: RP92178. [Epub ahead of print]12

Uncharacterized yeast gene YBR238C, an effector of TORC1 signaling in a mitochondrial feedback loop, accelerates cellular aging via HAP4- and RMD9-dependent mechanisms.

Mohammad Alfatah, Jolyn Jia Jia Lim, Yizhong Zhang, Arshia Naaz, Trishia Yi Ning Cheng, Sonia Yogasundaram, Nashrul Afiq Faidzinn, Jovian Jing Lin, Birgit Eisenhaber, Frank Eisenhaber.

  Uncovering the regulators of cellular aging will unravel the complexity of aging biology and identify potential therapeutic interventions to delay the onset and progress of chronic, aging-related diseases. In this work, we systematically compared genesets involved in regulating the lifespan of Saccharomyces cerevisiae (a powerful model organism to study the cellular aging of humans) and those with expression changes under rapamycin treatment. Among the functionally uncharacterized genes in the overlap set, YBR238C stood out as the only one downregulated by rapamycin and with an increased chronological and replicative lifespan upon deletion. We show that YBR238C and its paralog RMD9 oppositely affect mitochondria and aging. YBR238C deletion increases the cellular lifespan by enhancing mitochondrial function. Its overexpression accelerates cellular aging via mitochondrial dysfunction. We find that the phenotypic effect of YBR238C is largely explained by HAP4- and RMD9-dependent mechanisms. Furthermore, we find that genetic- or chemical-based induction of mitochondrial dysfunction increases TORC1 (Target of Rapamycin Complex 1) activity that, subsequently, accelerates cellular aging. Notably, TORC1 inhibition by rapamycin (or deletion of YBR238C) improves the shortened lifespan under these mitochondrial dysfunction conditions in yeast and human cells. The growth of mutant cells (a proxy of TORC1 activity) with enhanced mitochondrial function is sensitive to rapamycin whereas the growth of defective mitochondrial mutants is largely resistant to rapamycin compared to wild type. Our findings demonstrate a feedback loop between TORC1 and mitochondria (the TORC1-MItochondria-TORC1 (TOMITO) signaling process) that regulates cellular aging processes. Hereby, YBR238C is an effector of TORC1 modulating mitochondrial function.

Keywords:  S. cerevisiae; cellular aging; genetics; genomics; human; lifespan; mitochondria; nutrient signaling; target of rapamycin complex 1; uncharacterized genes

DOI:  https://doi.org/10.7554/eLife.92178
iScience. 2024 May 17. 27(5): 109699

The MCU and MCUb amino-terminal domains tightly interact: mechanisms for low conductance assembly of the mitochondrial calcium uniporter complex.

Megan Noble, Danielle M Colussi, Murray Junop, Peter B Stathopulos.

  The mitochondrial calcium (Ca2+) uniporter (MCU) complex is regulated via integration of the MCU dominant negative beta subunit (MCUb), a low conductance paralog of the main MCU pore forming protein. The MCU amino (N)-terminal domain (NTD) also modulates channel function through cation binding to the MCU regulating acidic patch (MRAP). MCU and MCUb have high sequence similarities, yet the structural and functional roles of MCUb-NTD remain unknown. Here, we report that MCUb-NTD exhibits α-helix/β-sheet structure with a high thermal stability, dependent on protein concentration. Remarkably, MCU- and MCUb-NTDs heteromerically interact with ∼nM affinity, increasing secondary structure and stability and structurally perturbing MRAP. Further, we demonstrate MCU and MCUb co-localization is suppressed upon NTD deletion concomitant with increased mitochondrial Ca2+ uptake. Collectively, our data show that MCU:MCUb NTD tight interactions are promoted by enhanced regular structure and stability, augmenting MCU:MCUb co-localization, lowering mitochondrial Ca2+ uptake and implicating an MRAP-sensing mechanism.

Keywords:  Cell biology; Structural biology

DOI:  https://doi.org/10.1016/j.isci.2024.109699
EMBO J. 2024 May 09.

A succinylation switch to maligancy: SUCLG1, mitochondrial transcription and leukemia.

Laura Guerrero, Panagiotis Ntziachristos.

DOI: https://doi.org/10.1038/s44318-024-00116-2
Cell Rep. 2024 May 06. pii: S2211-1247(24)00518-7. [Epub ahead of print]43(5): 114190

Dendrite architecture determines mitochondrial distribution patterns in vivo.

Eavan J Donovan, Anamika Agrawal, Nicole Liberman, Jordan I Kalai, Avi J Adler, Adam M Lamper, Hailey Q Wang, Nicholas J Chua, Elena F Koslover, Erin L Barnhart.

  Neuronal morphology influences synaptic connectivity and neuronal signal processing. However, it remains unclear how neuronal shape affects steady-state distributions of organelles like mitochondria. In this work, we investigated the link between mitochondrial transport and dendrite branching patterns by combining mathematical modeling with in vivo measurements of dendrite architecture, mitochondrial motility, and mitochondrial localization patterns in Drosophila HS (horizontal system) neurons. In our model, different forms of morphological and transport scaling rules-which set the relative thicknesses of parent and daughter branches at each junction in the dendritic arbor and link mitochondrial motility to branch thickness-predict dramatically different global mitochondrial localization patterns. We show that HS dendrites obey the specific subset of scaling rules that, in our model, lead to realistic mitochondrial distributions. Moreover, we demonstrate that neuronal activity does not affect mitochondrial transport or localization, indicating that steady-state mitochondrial distributions are hard-wired by the architecture of the neuron.

Keywords:  CP: Cell biology; CP: Neuroscience; dendrite scaling; in vivo imaging; mitochondrial motility; neuronal morphology

DOI:  https://doi.org/10.1016/j.celrep.2024.114190
Clin Case Rep. 2024 May;12(5): e8862

Mitochondrial diabetes plus phenotypes due to the m.3243A > G variant require correlation with heteroplasmy rates.

Josef Finsterer.

DOI: https://doi.org/10.1002/ccr3.8862
Ann Clin Transl Neurol. 2024 May 04.

Primary mitochondrial disorders and mimics: Insights from a large French cohort.

MitoDiag's Network Collaborators

OBJECTIVE: The objective of this study was to evaluate the implementation of NGS within the French mitochondrial network, MitoDiag, from targeted gene panels to whole exome sequencing (WES) or whole genome sequencing (WGS) focusing on mitochondrial nuclear-encoded genes.
METHODS: Over 2000 patients suspected of Primary Mitochondrial Diseases (PMD) were sequenced by either targeted gene panels, WES or WGS within MitoDiag. We described the clinical, biochemical, and molecular data of 397 genetically confirmed patients, comprising 294 children and 103 adults, carrying pathogenic or likely pathogenic variants in nuclear-encoded genes.
RESULTS: The cohort exhibited a large genetic heterogeneity, with the identification of 172 distinct genes and 253 novel variants. Among children, a notable prevalence of pathogenic variants in genes associated with oxidative phosphorylation (OXPHOS) functions and mitochondrial translation was observed. In adults, pathogenic variants were primarily identified in genes linked to mtDNA maintenance. Additionally, a substantial proportion of patients (54% (42/78) and 48% (13/27) in children and adults, respectively), undergoing WES or WGS testing displayed PMD mimics, representing pathologies that clinically resemble mitochondrial diseases.
INTERPRETATION: We reported the largest French cohort of patients suspected of PMD with pathogenic variants in nuclear genes. We have emphasized the clinical complexity of PMD and the challenges associated with recognizing and distinguishing them from other pathologies, particularly neuromuscular disorders. We confirmed that WES/WGS, instead of panel approach, was more valuable to identify the genetic basis in patients with "possible" PMD and we provided a genetic testing flowchart to guide physicians in their diagnostic strategy.

DOI: https://doi.org/10.1002/acn3.52062
Nature. 2024 May 08.

Major AlphaFold upgrade offers boost for drug discovery.

Ewen Callaway.



Keywords:  Drug discovery; Machine learning; Structural biology

DOI:  https://doi.org/10.1038/d41586-024-01383-z
J Obstet Gynaecol India. 2024 Apr;74(2): 176-178

Newborn Genetic Screening: Significance in Early Diagnosis of an Infant with Mitochondrial DNA Depletion Syndrome-6.

Sanjay A Gupte, Manju Kurup, Shweta M Jangam, Preeti Arora, Sarjan S Shah.

DOI: https://doi.org/10.1007/s13224-023-01770-y
FEBS J. 2024 May 06.

A new mutation in the Parkinson's-related FBXO7 gene impairs mitochondrial and proteasomal function.

Elisa Navarro, Noemí Esteras.

  Around 10% of Parkinson's disease (PD) cases are associated with mutations in various genes, including FBXO7, which encodes the substrate-recognition component for the Skp1-Cullin-F-box (SCF) class of ubiquitin E3 ligases that target proteins for proteasomal degradation. In their recent study, Al Rawi et al. characterized a new mutation in FBXO7, L250P, in a pediatric patient. Their findings reveal that the L250P mutation abolishes Fbxo7 interaction with the proteasome regulator, proteasome inhibitor 31kD (PI31), affecting proteasomal activity and the ubiquitination of some of the ligase's targets. Furthermore, the authors show that this previously undescribed mutation impairs mitochondrial function and mitophagy, emphasizing the importance of mitochondrial and proteasomal dysfunction in PD pathogenesis.

Keywords:  Fbxo7/PARK15; PI31/PSMF1; Parkinson; mitochondria; proteasome

DOI:  https://doi.org/10.1111/febs.17155
EMBO Mol Med. 2024 May 09.

How to treat a "sweetheart" in mitochondrial cardiomyopathy.

Hsin-Pin Lin, Derek P Narendra.

DOI: https://doi.org/10.1038/s44321-024-00070-w
Neuroscience. 2024 May 06. pii: S0306-4522(24)00173-8. [Epub ahead of print]

Lipid droplets and neurodegeneration.

Keya Mallick, Shuchismita Paul, Sayani Banerjee, Sugato Banerjee.

  Energy metabolism in the brain has been considered one of the critical research areas of neuroscience for ages. One of the most vital parts of brain metabolism cascades is lipid metabolism, and fatty acid plays a crucial role in this process. The fatty acid breakdown process in mitochondria undergoes through a conserved pathway known as β-oxidation where acetyl-CoA and shorter fatty acid chains are produced along with a significant amount of energy molecule. Further, the complete breakdown of fatty acids occurs when they enter the mitochondrial oxidative phosphorylation. Cells store energy as neutral lipids in organelles known as Lipid Droplets (LDs) to prepare for variations in the availability of nutrients. Fatty acids are liberated by lipid droplets and are transported to various cellular compartments for membrane biogenesis or as an energy source. Current research shows that LDs are important in inflammation, metabolic illness, and cellular communication. Lipid droplet biology in peripheral organs like the liver and heart has been well investigated, while the brain's LDs have received less attention. Recently, there has been increased awareness of the existence and role of these dynamic organelles in the central nervous system, mainly connected to neurodegeneration. In this review, we discussed the role of beta-oxidation and lipid droplet formation in the oxidative phosphorylation process, which directly affects neurodegeneration through various pathways.

Keywords:  Astrocyte; Lipids; Microglia; Mitochondria; Neurodegenerative disorders; Neuron

DOI:  https://doi.org/10.1016/j.neuroscience.2024.04.014
Nat Commun. 2024 May 10. 15(1): 3982

Spatial mapping of hepatic ER and mitochondria architecture reveals zonated remodeling in fasting and obesity.

Güneş Parlakgül, Song Pang, Leonardo L Artico, Nina Min, Erika Cagampan, Reyna Villa, Renata L S Goncalves, Grace Yankun Lee, C Shan Xu, Gökhan S Hotamışlıgil, Ana Paula Arruda.

The hepatocytes within the liver present an immense capacity to adapt to changes in nutrient availability. Here, by using high resolution volume electron microscopy, we map how hepatic subcellular spatial organization is regulated during nutritional fluctuations and as a function of liver zonation. We identify that fasting leads to remodeling of endoplasmic reticulum (ER) architecture in hepatocytes, characterized by the induction of single rough ER sheet around the mitochondria, which becomes larger and flatter. These alterations are enriched in periportal and mid-lobular hepatocytes but not in pericentral hepatocytes. Gain- and loss-of-function in vivo models demonstrate that the Ribosome receptor binding protein1 (RRBP1) is required to enable fasting-induced ER sheet-mitochondria interactions and to regulate hepatic fatty acid oxidation. Endogenous RRBP1 is enriched around periportal and mid-lobular regions of the liver. In obesity, ER-mitochondria interactions are distinct and fasting fails to induce rough ER sheet-mitochondrion interactions. These findings illustrate the importance of a regulated molecular architecture for hepatocyte metabolic flexibility.

DOI: https://doi.org/10.1038/s41467-024-48272-7
Neurobiol Dis. 2024 May 03. pii: S0969-9961(24)00121-9. [Epub ahead of print]196 106522

LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants.

Neda M Ilieva, Eric K Hoffman, Mohammed A Ghalib, J Timothy Greenamyre, Briana R De Miranda.

  Idiopathic Parkinson's disease (PD) is epidemiologically linked with exposure to toxicants such as pesticides and solvents, which comprise a wide array of chemicals that pollute our environment. While most are structurally distinct, a common cellular target for their toxicity is mitochondrial dysfunction, a key pathological trigger involved in the selective vulnerability of dopaminergic neurons. We and others have shown that environmental mitochondrial toxicants such as the pesticides rotenone and paraquat, and the organic solvent trichloroethylene (TCE) appear to be influenced by the protein LRRK2, a genetic risk factor for PD. As LRRK2 mediates vesicular trafficking and influences endolysosomal function, we postulated that LRRK2 kinase activity may inhibit the autophagic removal of toxicant damaged mitochondria, resulting in elevated oxidative stress. Conversely, we suspected that inhibition of LRRK2, which has been shown to be protective against dopaminergic neurodegeneration caused by mitochondrial toxicants, would reduce the intracellular production of reactive oxygen species (ROS) and prevent mitochondrial toxicity from inducing cell death. To do this, we tested in vitro if genetic or pharmacologic inhibition of LRRK2 (MLi2) protected against ROS caused by four toxicants associated with PD risk - rotenone, paraquat, TCE, and tetrachloroethylene (PERC). In parallel, we assessed if LRRK2 inhibition with MLi2 could protect against TCE-induced toxicity in vivo, in a follow up study from our observation that TCE elevated LRRK2 kinase activity in the nigrostriatal tract of rats prior to dopaminergic neurodegeneration. We found that LRRK2 inhibition blocked toxicant-induced ROS and promoted mitophagy in vitro, and protected against dopaminergic neurodegeneration, neuroinflammation, and mitochondrial damage caused by TCE in vivo. We also found that cells with the LRRK2 G2019S mutation displayed exacerbated levels of toxicant induced ROS, but this was ameliorated by LRRK2 inhibition with MLi2. Collectively, these data support a role for LRRK2 in toxicant-induced mitochondrial dysfunction linked to PD risk through oxidative stress and the autophagic removal of damaged mitochondria.

Keywords:  Environmental toxicants; Gene x environment (GxE); Leucine rich repeat kinase 2 (LRRK2); Mitochondria; Parkinson's disease (PD)

DOI:  https://doi.org/10.1016/j.nbd.2024.106522
Nat Mach Intell. 2023 Jul;5(7): 799-810

Federated benchmarking of medical artificial intelligence with MedPerf.

FeTS Consortium

Medical artificial intelligence (AI) has tremendous potential to advance healthcare by supporting and contributing to the evidence-based practice of medicine, personalizing patient treatment, reducing costs, and improving both healthcare provider and patient experience. Unlocking this potential requires systematic, quantitative evaluation of the performance of medical AI models on large-scale, heterogeneous data capturing diverse patient populations. Here, to meet this need, we introduce MedPerf, an open platform for benchmarking AI models in the medical domain. MedPerf focuses on enabling federated evaluation of AI models, by securely distributing them to different facilities, such as healthcare organizations. This process of bringing the model to the data empowers each facility to assess and verify the performance of AI models in an efficient and human-supervised process, while prioritizing privacy. We describe the current challenges healthcare and AI communities face, the need for an open platform, the design philosophy of MedPerf, its current implementation status and real-world deployment, our roadmap and, importantly, the use of MedPerf with multiple international institutions within cloud-based technology and on-premises scenarios. Finally, we welcome new contributions by researchers and organizations to further strengthen MedPerf as an open benchmarking platform.

DOI: https://doi.org/10.1038/s42256-023-00652-2
J Cell Biol. 2024 Jul 01. pii: e202309015. [Epub ahead of print]223(7):

A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy.

Dan A Tudorica, Bishal Basak, Alexia S Puerta Cordova, Grace Khuu, Kevin Rose, Michael Lazarou, Erika L F Holzbaur, James H Hurley.

Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.

DOI: https://doi.org/10.1083/jcb.202309015
Osong Public Health Res Perspect. 2024 Apr;15(2): 174-181

Establishment of a registry of clinical data and bioresources for rare nervous system diseases.

Dayoung Kim, Sooyoung Kim, Jin Myoung Seok, Kyong Jin Shin, Eungseok Oh, Mi Young Jeon, Joungkyu Park, Hee Jin Chang, Jinyoung Youn, Jeeyoung Oh, Eunhee Sohn, Jinse Park, Jin Whan Cho, Byoung Joon Kim.

  Rare diseases are predominantly genetic or inherited, and patients with these conditions frequently exhibit neurological symptoms. Diagnosing and treating many rare diseases is a complex challenge, and their low prevalence complicates the performance of research, which in turn hinders the advancement of therapeutic options. One strategy to address this issue is the creation of national or international registries for rare diseases, which can help researchers monitor and investigate their natural progression. In the Republic of Korea, we established a registry across 5 centers that focuses on 3 rare diseases, all of which are characterized by gait disturbances resulting from motor system dysfunction. The registry will collect clinical information and human bioresources from patients with amyotrophic lateral sclerosis, spinocerebellar ataxia, and hereditary spastic paraplegia. These resources will be stored at ICreaT and the National Biobank of Korea. Once the registry is complete, the data will be made publicly available for further research. Through this registry, our research team is dedicated to identifying genetic variants that are specific to Korean patients, uncovering biomarkers that show a strong correlation with clinical symptoms, and leveraging this information for early diagnosis and the development of treatments.

Keywords:  Data collection; Health resources; Nervous system; Rare diseases

DOI:  https://doi.org/10.24171/j.phrp.2023.0353
Nat Commun. 2024 May 04. 15(1): 3767

Giant organelle vesicles to uncover intracellular membrane mechanics and plasticity.

Alexandre Santinho, Maxime Carpentier, Julio Lopes Sampaio, Mohyeddine Omrane, Abdou Rachid Thiam.

Tools for accessing and studying organelles remain underdeveloped. Here, we present a method by which giant organelle vesicles (GOVs) are generated by submitting cells to a hypotonic medium followed by plasma membrane breakage. By this means, GOVs ranging from 3 to over 10 µm become available for micromanipulation. GOVs are made from organelles such as the endoplasmic reticulum, endosomes, lysosomes and mitochondria, or in contact with one another such as giant mitochondria-associated ER membrane vesicles. We measure the mechanical properties of each organelle-derived GOV and find that they have distinct properties. In GOVs procured from Cos7 cells, for example, bending rigidities tend to increase from the endoplasmic reticulum to the plasma membrane. We also found that the mechanical properties of giant endoplasmic reticulum vesicles (GERVs) vary depending on their interactions with other organelles or the metabolic state of the cell. Lastly, we demonstrate GERVs' biochemical activity through their capacity to synthesize triglycerides and assemble lipid droplets. These findings underscore the potential of GOVs as valuable tools for studying the biophysics and biology of organelles.

DOI: https://doi.org/10.1038/s41467-024-48086-7
J Cell Signal. 2023 ;4(4): 151-162

Depleting Cellular Retinoic Acid Binding Protein 1 Impairs UPRmt.

Chin-Wen Wei, Thomas Lerdall, Fatimah Najjar, Li-Na Wei.

  Mitochondrial dysfunction underlines neurodegenerative diseases which are mostly characterized by progressive degeneration of neurons. We previously reported that Cellular retinoic acid Binding protein 1 (Crabp1) knockout (CKO) mice spontaneously developed age-dependent motor degeneration, with defects accumulated in spinal motor neurons (MNs), the only cell type in spinal cord that expresses CRABP1. Here we uncovered that mitochondrial DNA (mtDNA) content and the expression of genes involved in respiration were significantly reduced in CKO mouse spinal cord, accompanied by significantly elevated reactive oxygen species (ROS) and unfolded protein load, indicating that CRABP1 deficiency caused mitochondrial dysfunction. Further analyses of spinal cord tissues revealed significant reduction in the expression and activity of superoxide dismutase 2 (SOD2), as well as defected mitochondrial unfolded protein response (UPRmt) pathway, specifically an increase in ATF5 mRNA but not its protein level, which suggested failure in the translational response of ATF5 in CKO. Consistently, eukaryotic initiation factor-2α, (eIF2α) phosphorylation was reduced in CKO spinal cord. In a CRABP1 knockdown MN1 model, siCrabp1-MN1, we validated the cell-autonomous function of CRABP1 in modulating the execution of UPRmt. This study reveals a new functional role for CRABP1 in the execution of mitochondrial stress response, that CRABP1 modulates eIF2α phosphorylation thereby contributing to ATF5 translational response that is needed to mitigate mitochondria stress.

Keywords:  Crabp1; Reactive oxygen species; Unfolded protein response; eIF2α

DOI:  https://doi.org/10.33696/signaling.4.102
Nat Med. 2024 May 09.

Gene therapy trials deliver double win.

Karen O'Leary.



Keywords:  Clinical trials; Gene therapy

DOI:  https://doi.org/10.1038/d41591-024-00033-1
J Clin Invest. 2024 May 09. pii: e165482. [Epub ahead of print]

Mitochondria regulate proliferation in adult cardiac myocytes.

Gregory B Waypa, Kimberly A Smith, Paul T Mungai, Vincent J Dudley, Kathryn A Helmin, Benjamin D Singer, Clara Bien Peek, Joseph Bass, Lauren Beussink-Nelson, Sanjiv J Shah, Gaston Ofman, J Andrew Wasserstrom, William A Muller, Alexander V Misharin, G R Scott Budinger, Hiam Abdala-Valencia, Navdeep S Chandel, Danijela Dokic, Elizabeth T Bartom, Shuang Zhang, Yuki Tatekoshi, Amir Mahmoodzadeh, Hossein Ardehali, Edward B Thorp, Paul T Schumacker.

  Newborn mammalian cardiomyocytes quickly transition from a fetal to an adult phenotype that utilizes mitochondrial oxidative phosphorylation but loses mitotic capacity. We tested whether forced reversal of adult cardiomyocytes back to a fetal glycolytic phenotype would restore proliferative capacity. We deleted Uqcrfs1 (mitochondrial Rieske Iron-Sulfur protein, RISP) in hearts of adult mice. As RISP protein decreased, heart mitochondrial function declined, and glucose utilization increased. Simultaneously, they underwent hyperplastic remodeling during which cardiomyocyte number doubled without cellular hypertrophy. Cellular energy supply was preserved, AMPK activation was absent, and mTOR activation was evident. In ischemic hearts with RISP deletion, new cardiomyocytes migrated into the infarcted region, suggesting the potential for therapeutic cardiac regeneration. RNA-seq revealed upregulation of genes associated with cardiac development and proliferation. Metabolomic analysis revealed a decrease in alpha-ketoglutarate (required for TET-mediated demethylation) and an increase in S-adenosylmethionine (required for methyltransferase activity). Analysis revealed an increase in methylated CpGs near gene transcriptional start sites. Genes that were both differentially expressed and differentially methylated were linked to upregulated cardiac developmental pathways. We conclude that decreased mitochondrial function and increased glucose utilization can restore mitotic capacity in adult cardiomyocytes resulting in the generation of new heart cells, potentially through the modification of substrates that regulate epigenetic modification of genes required for proliferation.

Keywords:  Bioenergetics; Cardiology; Cardiovascular disease; Metabolism; Mitochondria

DOI:  https://doi.org/10.1172/JCI165482
Nat Rev Nephrol. 2024 May 08.

Spatial transcriptomics in health and disease.

Sanjay Jain, Michael T Eadon.

The ability to localize hundreds of macromolecules to discrete locations, structures and cell types in a tissue is a powerful approach to understand the cellular and spatial organization of an organ. Spatially resolved transcriptomic technologies enable mapping of transcripts at single-cell or near single-cell resolution in a multiplex manner. The rapid development of spatial transcriptomic technologies has accelerated the pace of discovery in several fields, including nephrology. Its application to preclinical models and human samples has provided spatial information about new cell types discovered by single-cell sequencing and new insights into the cell-cell interactions within neighbourhoods, and has improved our understanding of the changes that occur in response to injury. Integration of spatial transcriptomic technologies with other omics methods, such as proteomics and spatial epigenetics, will further facilitate the generation of comprehensive molecular atlases, and provide insights into the dynamic relationships of molecular components in homeostasis and disease. This Review provides an overview of current and emerging spatial transcriptomic methods, their applications and remaining challenges for the field.

DOI: https://doi.org/10.1038/s41581-024-00841-1
Orphanet J Rare Dis. 2024 May 07. 19(1): 190

Innovative methodologies for rare diseases clinical trials.

Rima Nabbout, Ralf-Dieter Hilgers.

DOI: https://doi.org/10.1186/s13023-024-03189-8
bioRxiv. 2024 Apr 24. pii: 2024.04.24.590854. [Epub ahead of print]

Enigmatic missense mutations can cause disease via creation of de novo nuclear export signals.

By Michael McConville, Toby Thomas, Ryan Beckner, Catherine Valadez, YuhMin Chook, Stephen Chung, Glen Liszczak.

Disease-causing missense mutations that occur within structurally and functionally unannotated protein regions can guide researchers to new mechanisms of protein regulation and dysfunction. Here, we report that the thrombocytopenia-, myelodysplastic syndromes-, and leukemia-associated P214L mutation in the transcriptional regulator ETV6 creates an XPO1-dependent nuclear export signal to cause protein mislocalization. Strategies to disrupt XPO1 activity fully restore ETV6 P214L protein nuclear localization and transcription regulation activity. Mechanistic insight inspired the design of a 'humanized' ETV6 mice, which we employ to demonstrate that the germline P214L mutation is sufficient to elicit severe defects in thrombopoiesis and hematopoietic stem cell maintenance. Beyond ETV6, we employed computational methods to uncover rare disease-associated missense mutations in unrelated proteins that create a nuclear export signal to disrupt protein function. Thus, missense mutations that operate through this mechanism should be predictable and may suggest rational therapeutic strategies for associated diseases.

DOI: https://doi.org/10.1101/2024.04.24.590854