bims-tofagi 2024-09-22 papers

J Biol Chem. 2024 Sep 12. pii: S0021-9258(24)02276-2. [Epub ahead of print] 107775

TBK1 adaptor AZI2/NAP1 regulates NDP52-driven mitochondrial autophagy.

Ryu Endo, Hiroki Kinefuchi, Momoha Sawada, Reika Kikuchi, Waka Kojima, Noriyuki Matsuda, Koji Yamano.

Damaged mitochondria are selectively eliminated in a process called mitophagy. PINK1 and Parkin amplify ubiquitin signals on damaged mitochondria, which are then recognized by autophagy adaptors to induce local autophagosome formation. NDP52 and OPTN, two essential mitophagy adaptors, facilitate de novo synthesis of pre-autophagosomal membranes near damaged mitochondria by linking ubiquitinated mitochondria and ATG8 family proteins and by recruiting core autophagy initiation components. The multifunctional serine/threonine kinase TBK1 also plays important roles in mitophagy. OPTN directly binds TBK1 to form a positive feedback loop for isolation membrane expansion. TBK1 is also thought to indirectly interact with NDP52; however, its role in NDP52-driven mitophagy remains largely unknown. Here, we focused on two TBK1 adaptors, AZI2/NAP1 and TBKBP1/SINTBAD, that are thought to mediate the TBK1-NDP52 interaction. We found that both AZI2 and TBKBP1 are recruited to damaged mitochondria during Parkin-mediated mitophagy. Further, a series of AZI2 and TBKBP1 knockout constructs combined with an OPTN knockout showed that AZI2, but not TBKBP1, impacts NDP52-driven mitophagy. In addition, we found that AZI2 at S318 is phosphorylated during mitophagy, the impairment of which slightly inhibits mitochondrial degradation. These results suggest that AZI2, in concert with TBK1, plays an important role in NDP52-driven mitophagy.

Keywords: autophagy; mitochondria; mitophagy; polyubiquitin chain; serine/threonine protein kinase

DOI: https://doi.org/10.1016/j.jbc.2024.107775

Nat Commun. 2024 Sep 19. 15(1): 7707

Activation of parkin by a molecular glue.

Véronique Sauvé, Eric Stefan, Nathalie Croteau, Thomas Goiran, Rayan Fakih, Nupur Bansal, Adelajda Hadzipasic, Jing Fang, Paramasivam Murugan, Shimin Chen, Edward A Fon, Warren D Hirst, Laura F Silvian, Jean-François Trempe, Kalle Gehring.

Mutations in parkin and PINK1 cause early-onset Parkinson's disease (EOPD). The ubiquitin ligase parkin is recruited to damaged mitochondria and activated by PINK1, a kinase that phosphorylates ubiquitin and the ubiquitin-like domain of parkin. Activated phospho-parkin then ubiquitinates mitochondrial proteins to target the damaged organelle for degradation. Here, we present the mechanism of activation of a new class of small molecule allosteric modulators that enhance parkin activity. The compounds act as molecular glues to enhance the ability of phospho-ubiquitin (pUb) to activate parkin. Ubiquitination assays and isothermal titration calorimetry with the most active compound (BIO-2007817) identify the mechanism of action. We present the crystal structure of a closely related compound (BIO-1975900) bound to a complex of parkin and two pUb molecules. The compound binds next to pUb on RING0 and contacts both proteins. Hydrogen-deuterium exchange mass spectrometry (HDX-MS) experiments confirm that activation occurs through release of the catalytic Rcat domain. In organello and mitophagy assays demonstrate that BIO-2007817 partially rescues the activity of parkin EOPD mutants, R42P and V56E, offering a basis for the design of activators as therapeutics for Parkinson's disease.

DOI: https://doi.org/10.1038/s41467-024-51889-3

Mol Neurobiol. 2024 Sep 18.

Urolithin a Improves Motor Dysfunction Induced by Copper Exposure in SOD1G93A Transgenic Mice Via Activation of Mitophagy.

Huan Zhang, Chuanyue Gao, Deguang Yang, Lulin Nie, Kaiwu He, Chongyang Chen, Shangming Li, Guanqin Huang, Li Zhou, Xinfeng Huang, Desheng Wu, Jianjun Liu, Zhenlie Huang, Jie Wang, Weihua Li, Zhaohui Zhang, Xifei Yang, Liangyu Zou.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease pathologically characterized by selective degeneration of motor neurons resulting in a catastrophic loss of motor function. The present study aimed to investigate the effect of copper (Cu) exposure on progression of ALS and explore the therapeutic effect and mechanism of Urolithin A (UA) on ALS. 0.13 PPM copper chloride drinking water was administrated in SOD1G93A transgenic mice at 6 weeks, UA at a dosage of 50 mg/kg/day was given for 6 weeks after a 7-week Cu exposure. Motor ability was assessed before terminal anesthesia. Muscle atrophy and fibrosis, motor neurons, astrocytes and microglia in the spinal cord were evaluated by H&E, Masson, Sirius Red, Nissl and Immunohistochemistry Staining. Proteomics analysis, Western blotting and ELISA were conducted to detect protein expression. Mitochondrial adenosine triphosphate (ATP) and malondialdehyde (MDA) levels were measured using an assay kit. Cu-exposure worsened motor function, promoted muscle fibrosis, loss of motor neurons, and astrocyte and microglial activation. It also induced abnormal changes in mitochondria-related biological processes, leading to a significant reduction in ATP levels and an increase in MDA levels. Upregulation of P62 and downregulation of Parkin, PINK1, and LAMP1 were revealed in SOD1G93A mice with Cu exposure. Administration of UA activated mitophagy, modulated mitochondria dysfunction, reduced neuroinflammation, and improved gastrocnemius muscle atrophy and motor dysfunction in SOD1G93A mice with Cu exposure. Mitophagy plays critical role in ALS exacerbated by Cu exposure. UA administration may be a promising treatment strategy for ALS.

Keywords: Amyotrophic lateral sclerosis; Copper; Mitophagy; Motor dysfunction; Urolithin A

DOI: https://doi.org/10.1007/s12035-024-04473-1

J Biol Chem. 2024 Sep 12. pii: S0021-9258(24)02274-9. [Epub ahead of print] 107773

Subcellular localization and function analysis of PINK1 mitron in PD progression: mitron modulates mitochondrial morphology to regulate neuronal death.

Yu Qiao, Jiayuan Kou, Ye Tian, Wenkai Ma, Yang Yu, Jingjing Pang, Yingting Pei, Yu Zhang, Bin Ye, Ziying Xie, Jinying Liu, Zhihui Wang, Lujing Wang, Xu Gao, Ning Ma, Yanfen Zhang.

Parkinson's disease (PD) is a multi-factorial neurodegenerative disorder. Loss or degeneration of the dopaminergic neurons in the substantia nigra and development of Lewy Bodies in dopaminergic neurons were the defining pathologic changes. MiRNAs fine-tune the protein levels by post-transcriptional gene regulation. MiR-7019-3p is encoded within the 5th intron of PD associated protein PINK1. In present study, we firstly demonstrated miR-7019-3p expression is significantly up regulated in PD mice model and neuron cell models, miR-7019-3p mainly existed in mitochondria, miR-7019-3p could regulate the structure and function of mitochondria in neuronal cells. We predicted and verified that mitochondria associated protein OPA1 and 12s rRNA, 16s rRNA and polycistronic RNA are target genes of miR-7019-3p. Finally, we proved that SP1 protein could independently regulate the expression of miR-7019-3p at the upstream. The evidences in the study suggest the role miR-7019-3p in the regulation of mitochondrial structure and function, and this kind of regulation could be implemented or promoted through the pathway of SP1-miR-7019-3p-OPA1/12s rRNA, 16s rRNA and polycistronic RNA. Our results have suggested a promising and potential therapeutic target for reversing mitochondria dysregulation in neuronal cells during Parkinson's disease process.

DOI: https://doi.org/10.1016/j.jbc.2024.107773