1
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Kan KT, Wilcock J, Lu H. Role of Yme1 in mitochondrial protein homeostasis: from regulation of protein import, OXPHOS function to lipid synthesis and mitochondrial dynamics. Biochem Soc Trans 2024; 52:1539-1548. [PMID: 38864432 DOI: 10.1042/bst20240450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/29/2024] [Accepted: 05/30/2024] [Indexed: 06/13/2024]
Abstract
Mitochondria are essential organelles of eukaryotic cells and thus mitochondrial proteome is under constant quality control and remodelling. Yme1 is a multi-functional protein and subunit of the homo-hexametric complex i-AAA proteinase. Yme1 plays vital roles in the regulation of mitochondrial protein homeostasis and mitochondrial plasticity, ranging from substrate degradation to the regulation of protein functions involved in mitochondrial protein biosynthesis, energy production, mitochondrial dynamics, and lipid biosynthesis and signalling. In this mini review, we focus on discussing the current understanding of the roles of Yme1 in mitochondrial protein import via TIM22 and TIM23 pathways, oxidative phosphorylation complex function, as well as mitochondrial lipid biosynthesis and signalling, as well as a brief discussion of the role of Yme1 in modulating mitochondrial dynamics.
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Affiliation(s)
- Kwan Ting Kan
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, U.K
| | - Joel Wilcock
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, U.K
| | - Hui Lu
- School of Biological Sciences, Faculty of Biology, Medicine and Health, Manchester Academic Health Science Centre, The University of Manchester, Manchester M13 9PT, U.K
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2
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Yang M, Chen S, Lim SL, Yang L, Zhong JY, Chan KC, Zhao Z, Wong KB, Wang J, Lim BL. A converged ubiquitin-proteasome pathway for the degradation of TOC and TOM tail-anchored receptors. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2024; 66:1007-1023. [PMID: 38501483 DOI: 10.1111/jipb.13645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 02/27/2024] [Indexed: 03/20/2024]
Abstract
In plants, thousands of nucleus-encoded proteins translated in the cytosol are sorted to chloroplasts and mitochondria by binding to specific receptors of the TOC (translocon on the outer chloroplast membrane) and the TOM (translocon on the outer mitochondrial membrane) complexes for import into those organelles. The degradation pathways for these receptors are unclear. Here, we discovered a converged ubiquitin-proteasome pathway for the degradation of Arabidopsis thaliana TOC and TOM tail-anchored receptors. The receptors are ubiquitinated by E3 ligase(s) and pulled from the outer membranes by the AAA+ adenosine triphosphatase CDC48, after which a previously uncharacterized cytosolic protein, transmembrane domain (TMD)-binding protein for tail-anchored outer membrane proteins (TTOP), binds to the exposed TMDs at the C termini of the receptors and CDC48, and delivers these complexes to the 26S proteasome.
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Affiliation(s)
- Meijing Yang
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Shuai Chen
- School of Biomedical Engineering, Shenzhen University, Shenzhen, 518060, China
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, 999077, Hong Kong, China
| | - Shey-Li Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
| | - Lang Yang
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Jia Yi Zhong
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
| | - Koon Chuen Chan
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
| | - Zhizhu Zhao
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
| | - Kam-Bo Wong
- School of Life Sciences, The Chinese University of Hong Kong, Shatin, 999077, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, 999077, Hong Kong, China
| | - Junqi Wang
- Department of Biology, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Boon Leong Lim
- School of Biological Sciences, University of Hong Kong, Pokfulam, 999077, Hong Kong, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, 999077, Hong Kong, China
- HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518052, China
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3
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Gerber M, Suppanz I, Oeljeklaus S, Niemann M, Käser S, Warscheid B, Schneider A, Dewar CE. A Msp1-containing complex removes orphaned proteins in the mitochondrial outer membrane of T. brucei. Life Sci Alliance 2023; 6:e202302004. [PMID: 37586887 PMCID: PMC10432679 DOI: 10.26508/lsa.202302004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 07/27/2023] [Accepted: 07/31/2023] [Indexed: 08/18/2023] Open
Abstract
The AAA-ATPase Msp1 extracts mislocalised outer membrane proteins and thus contributes to mitochondrial proteostasis. Using pulldown experiments, we show that trypanosomal Msp1 localises to both glycosomes and the mitochondrial outer membrane, where it forms a complex with four outer membrane proteins. The trypanosome-specific pATOM36 mediates complex assembly of α-helically anchored mitochondrial outer membrane proteins such as protein translocase subunits. Inhibition of their assembly triggers a pathway that results in the proteasomal digestion of unassembled substrates. Using inducible single, double, and triple RNAi cell lines combined with proteomic analyses, we demonstrate that not only Msp1 but also the trypanosomal homolog of the AAA-ATPase VCP are implicated in this quality control pathway. Moreover, in the absence of VCP three out of the four Msp1-interacting mitochondrial proteins are required for efficient proteasomal digestion of pATOM36 substrates, suggesting they act in concert with Msp1. pATOM36 is a functional analog of the yeast mitochondrial import complex complex and possibly of human mitochondrial animal-specific carrier homolog 2, suggesting that similar mitochondrial quality control pathways linked to Msp1 might also exist in yeast and humans.
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Affiliation(s)
- Markus Gerber
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Ida Suppanz
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Moritz Niemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Sandro Käser
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Bettina Warscheid
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - André Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
- Institute for Advanced Study (Wissenschaftskolleg) Berlin, Berlin, Germany
| | - Caroline E Dewar
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
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4
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He J, Liu K, Wu Y, Zhao C, Yan S, Chen JH, Hu L, Wang D, Zheng F, Wei W, Xu C, Huang C, Liu X, Yao X, Ding L, Fang Z, Tang AH, Fu C. The AAA-ATPase Yta4/ATAD1 interacts with the mitochondrial divisome to inhibit mitochondrial fission. PLoS Biol 2023; 21:e3002247. [PMID: 37590302 PMCID: PMC10465003 DOI: 10.1371/journal.pbio.3002247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/29/2023] [Accepted: 07/12/2023] [Indexed: 08/19/2023] Open
Abstract
Mitochondria are in a constant balance of fusion and fission. Excessive fission or deficient fusion leads to mitochondrial fragmentation, causing mitochondrial dysfunction and physiological disorders. How the cell prevents excessive fission of mitochondria is not well understood. Here, we report that the fission yeast AAA-ATPase Yta4, which is the homolog of budding yeast Msp1 responsible for clearing mistargeted tail-anchored (TA) proteins on mitochondria, plays a critical role in preventing excessive mitochondrial fission. The absence of Yta4 leads to mild mitochondrial fragmentation in a Dnm1-dependent manner but severe mitochondrial fragmentation upon induction of mitochondrial depolarization. Overexpression of Yta4 delocalizes the receptor proteins of Dnm1, i.e., Fis1 (a TA protein) and Mdv1 (the bridging protein between Fis1 and Dnm1), from mitochondria and reduces the localization of Dnm1 to mitochondria. The effect of Yta4 overexpression on Fis1 and Mdv1, but not Dnm1, depends on the ATPase and translocase activities of Yta4. Moreover, Yta4 interacts with Dnm1, Mdv1, and Fis1. In addition, Yta4 competes with Dnm1 for binding Mdv1 and decreases the affinity of Dnm1 for GTP and inhibits Dnm1 assembly in vitro. These findings suggest a model, in which Yta4 inhibits mitochondrial fission by inhibiting the function of the mitochondrial divisome composed of Fis1, Mdv1, and Dnm1. Therefore, the present work reveals an uncharacterized molecular mechanism underlying the inhibition of mitochondrial fission.
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Affiliation(s)
- Jiajia He
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Ke Liu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Yifan Wu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Chenhui Zhao
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Shuaijie Yan
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Jia-Hui Chen
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Lizhu Hu
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Dongmei Wang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Fan Zheng
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Wenfan Wei
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Chao Xu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Chengdong Huang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xing Liu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Xuebiao Yao
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Lijun Ding
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, The Affiliated Drum Tower Hospital of Nanjing University Medical School, Nanjing, China
| | - Zhiyou Fang
- Anhui Province Key Laboratory of Medical Physics and Technology, Institute of Health and Medical Technology, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, China
| | - Ai-Hui Tang
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Chuanhai Fu
- MOE Key Laboratory for Cellular Dynamics & Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology & Hefei National Research Center for Interdisciplinary Sciences at the Microscale, School of Life Sciences, University of Science and Technology of China, Hefei, China
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5
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Connelly EM, Frankel KS, Shaw GS. Parkin and mitochondrial signalling. Cell Signal 2023; 106:110631. [PMID: 36803775 DOI: 10.1016/j.cellsig.2023.110631] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/19/2023]
Abstract
Aging, toxic chemicals and changes to the cellular environment are sources of oxidative damage to mitochondria which contribute to neurodegenerative conditions including Parkinson's disease. To counteract this, cells have developed signalling mechanisms to identify and remove select proteins and unhealthy mitochondria to maintain homeostasis. Two important proteins that work in concert to control mitochondrial damage are the protein kinase PINK1 and the E3 ligase parkin. In response to oxidative stress, PINK1 phosphorylates ubiquitin present on proteins at the mitochondrial surface. This signals the translocation of parkin, accelerates further phosphorylation, and stimulates ubiquitination of outer mitochondrial membrane proteins such as Miro1/2 and Mfn1/2. The ubiquitination of these proteins is the key step needed to target them for degradation via the 26S proteasomal machinery or eliminate the entire organelle through mitophagy. This review highlights the signalling mechanisms used by PINK1 and parkin and presents several outstanding questions yet to be resolved.
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Affiliation(s)
- Elizabeth M Connelly
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Karling S Frankel
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Gary S Shaw
- Department of Biochemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada.
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6
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Zheng J, Cao Y, Yang J, Jiang H. UBXD8 mediates mitochondria-associated degradation to restrain apoptosis and mitophagy. EMBO Rep 2022; 23:e54859. [PMID: 35979733 PMCID: PMC9535754 DOI: 10.15252/embr.202254859] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 07/20/2022] [Accepted: 08/04/2022] [Indexed: 08/08/2023] Open
Abstract
The hexameric AAA-ATPase valosin-containing protein (VCP) is essential for mitochondrial protein quality control. How VCP is recruited to mammalian mitochondria remains obscure. Here we report that UBXD8, an ER- and lipid droplet-localized VCP adaptor, also localizes to mitochondria and locally recruits VCP. UBXD8 associates with mitochondrial and ER ubiquitin E3 ligases and targets their substrates for degradation. Remarkably, both mitochondria- and ER-localized UBXD8 can degrade mitochondrial and ER substrates in cis and in trans. UBXD8 also associates with the TOM complex but is dispensable for translocation-associated degradation. UBXD8 knockout impairs the degradation of the pro-survival protein Mcl1 but surprisingly sensitizes cells to apoptosis and mitochondrial stresses. UBXD8 knockout also hyperactivates mitophagy. We identify pro-apoptotic BH3-only proteins Noxa, Bik, and Bnip3 as novel UBXD8 substrates and determine that UBXD8 inhibits apoptosis via degrading Noxa and restrains mitophagy via degrading Bnip3. Collectively, our characterizations reveal UBXD8 as the major mitochondrial adaptor of VCP and unveil its role in apoptosis and mitophagy regulation.
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Affiliation(s)
- Jing Zheng
- School of Life SciencesPeking UniversityBeijingChina
- National Institute of Biological SciencesBeijingChina
- Beijing Key Laboratory of Cell Biology for Animal AgingBeijingChina
| | - Yu Cao
- National Institute of Biological SciencesBeijingChina
- Beijing Key Laboratory of Cell Biology for Animal AgingBeijingChina
- College of Life SciencesBeijing Normal UniversityBeijingChina
| | - Jun Yang
- National Institute of Biological SciencesBeijingChina
- Beijing Key Laboratory of Cell Biology for Animal AgingBeijingChina
- School of Life SciencesTsinghua UniversityBeijingChina
| | - Hui Jiang
- School of Life SciencesPeking UniversityBeijingChina
- National Institute of Biological SciencesBeijingChina
- Beijing Key Laboratory of Cell Biology for Animal AgingBeijingChina
- Tsinghua Institute of Multidisciplinary Biomedical ResearchTsinghua UniversityBeijingChina
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7
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Reynaud K, Brothers M, Ly M, Ingolia NT. Dynamic post-transcriptional regulation by Mrn1 links cell wall homeostasis to mitochondrial structure and function. PLoS Genet 2021; 17:e1009521. [PMID: 33857138 PMCID: PMC8079021 DOI: 10.1371/journal.pgen.1009521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 04/27/2021] [Accepted: 03/29/2021] [Indexed: 12/25/2022] Open
Abstract
The RNA-binding protein Mrn1 in Saccharomyces cerevisiae targets over 300 messenger RNAs, including many involved in cell wall biogenesis. The impact of Mrn1 on these target transcripts is not known, however, nor is the cellular role for this regulation. We have shown that Mrn1 represses target mRNAs through the action of its disordered, asparagine-rich amino-terminus. Its endogenous targets include the paralogous SUN domain proteins Nca3 and Uth1, which affect mitochondrial and cell wall structure and function. While loss of MRN1 has no effect on fermentative growth, we found that mrn1Δ yeast adapt more quickly to respiratory conditions. These cells also have enlarged mitochondria in fermentative conditions, mediated in part by dysregulation of NCA3, and this may explain their faster switch to respiration. Our analyses indicated that Mrn1 acts as a hub for integrating cell wall integrity and mitochondrial biosynthesis in a carbon-source responsive manner.
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Affiliation(s)
- Kendra Reynaud
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
| | - Molly Brothers
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Michael Ly
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
| | - Nicholas T. Ingolia
- California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, California, United States of America
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America
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8
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He Y, Makarczyk MJ, Lin H. Role of mitochondria in mediating chondrocyte response to mechanical stimuli. Life Sci 2020; 263:118602. [PMID: 33086121 PMCID: PMC7736591 DOI: 10.1016/j.lfs.2020.118602] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/22/2020] [Accepted: 10/11/2020] [Indexed: 12/21/2022]
Abstract
As the most common form of arthritis, osteoarthritis (OA) has become a major cause of severe joint pain, physical disability, and quality of life impairment in the affected population. To date, precise pathogenesis of OA has not been fully clarified, which leads to significant obstacles in developing efficacious treatments such as failures in finding disease-modifying OA drugs (DMOADs) in the last decades. Given that diarthrodial joints primarily display the weight-bearing and movement-supporting function, it is not surprising that mechanical stress represents one of the major risk factors for OA. However, the inner connection between mechanical stress and OA onset/progression has yet to be explored. Mitochondrion, a widespread organelle involved in complex biological regulation processes such as adenosine triphosphate (ATP) synthesis and cellular metabolism, is believed to have a controlling role in the survival and function implement of chondrocytes, the singular cell type within cartilage. Mitochondrial dysfunction has also been observed in osteoarthritic chondrocytes. In this review, we systemically summarize mitochondrial alterations in chondrocytes during OA progression and discuss our recent progress in understanding the potential role of mitochondria in mediating mechanical stress-associated osteoarthritic alterations of chondrocytes. In particular, we propose the potential signaling pathways that may regulate this process, which provide new views and therapeutic targets for the prevention and treatment of mechanical stress-associated OA.
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Affiliation(s)
- Yuchen He
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Meagan J Makarczyk
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States of America; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Hang Lin
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States of America; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States of America.
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9
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Jiang H. Quality control pathways of tail-anchored proteins. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118922. [PMID: 33285177 DOI: 10.1016/j.bbamcr.2020.118922] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/14/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022]
Abstract
Tail-anchored (TA) proteins have an N-terminal domain in the cytosol and a C-terminal transmembrane domain anchored to a variety of organelle membranes. TA proteins are recognized by targeting factors at the transmembrane domain and C-terminal sequence and are guided to distinct membranes. The promiscuity of targeting sequences and the dysfunction of targeting pathways cause mistargeting of TA proteins. TA proteins are under surveillance by quality control pathways. For resident TA proteins at mitochondrial and ER membranes, intrinsic instability or stimuli induced degrons of the cytosolic and transmembrane domains are sensed by quality control factors to initiate degradation of TA proteins. These pathways are summarized as TA protein degradation-Cytosol (TAD-C) and TAD-Membrane (TAD-M) pathways. For mistargeted and a subset of solitary TA proteins at mitochondrial and peroxisomal membranes, a unique pathway has been revealed in recent years. Msp1/ATAD1 is an AAA-ATPase dually-localized to mitochondrial and peroxisomal membranes. It directly recognizes mistargeted and solitary TA proteins and dislocates them out of membrane. Dislocated substrates are subsequently ubiquitinated by the ER-resident Doa10 ubiquitin E3 ligase complex for degradation. We summarize and discuss the substrate recognition, dislocation and degradation mechanisms of the Msp1 pathway.
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Affiliation(s)
- Hui Jiang
- National Institute of Biological Sciences, Beijing 102206, China; Beijing Key Laboratory of Cell Biology for Animal Aging, Beijing 102206, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 100871, China.
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10
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Escobar-Henriques M, Anton V. Mitochondrial Surveillance by Cdc48/p97: MAD vs. Membrane Fusion. Int J Mol Sci 2020; 21:E6841. [PMID: 32961852 PMCID: PMC7555132 DOI: 10.3390/ijms21186841] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 09/07/2020] [Accepted: 09/08/2020] [Indexed: 11/16/2022] Open
Abstract
Cdc48/p97 is a ring-shaped, ATP-driven hexameric motor, essential for cellular viability. It specifically unfolds and extracts ubiquitylated proteins from membranes or protein complexes, mostly targeting them for proteolytic degradation by the proteasome. Cdc48/p97 is involved in a multitude of cellular processes, reaching from cell cycle regulation to signal transduction, also participating in growth or death decisions. The role of Cdc48/p97 in endoplasmic reticulum-associated degradation (ERAD), where it extracts proteins targeted for degradation from the ER membrane, has been extensively described. Here, we present the roles of Cdc48/p97 in mitochondrial regulation. We discuss mitochondrial quality control surveillance by Cdc48/p97 in mitochondrial-associated degradation (MAD), highlighting the potential pathologic significance thereof. Furthermore, we present the current knowledge of how Cdc48/p97 regulates mitofusin activity in outer membrane fusion and how this may impact on neurodegeneration.
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Affiliation(s)
- Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Straße 26, 50931 Cologne, Germany;
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11
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Ravanelli S, den Brave F, Hoppe T. Mitochondrial Quality Control Governed by Ubiquitin. Front Cell Dev Biol 2020; 8:270. [PMID: 32391359 PMCID: PMC7193050 DOI: 10.3389/fcell.2020.00270] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/30/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are essential organelles important for energy production, proliferation, and cell death. Biogenesis, homeostasis, and degradation of this organelle are tightly controlled to match cellular needs and counteract chronic stress conditions. Despite providing their own DNA, the vast majority of mitochondrial proteins are encoded in the nucleus, synthesized by cytosolic ribosomes, and subsequently imported into different mitochondrial compartments. The integrity of the mitochondrial proteome is permanently challenged by defects in folding, transport, and turnover of mitochondrial proteins. Therefore, damaged proteins are constantly sequestered from the outer mitochondrial membrane and targeted for proteasomal degradation in the cytosol via mitochondrial-associated degradation (MAD). Recent studies identified specialized quality control mechanisms important to decrease mislocalized proteins, which affect the mitochondrial import machinery. Interestingly, central factors of these ubiquitin-dependent pathways are shared with the ER-associated degradation (ERAD) machinery, indicating close collaboration between both tubular organelles. Here, we summarize recently described cellular stress response mechanisms, which are triggered by defects in mitochondrial protein import and quality control. Moreover, we discuss how ubiquitin-dependent degradation is integrated with cytosolic stress responses, particularly focused on the crosstalk between MAD and ERAD.
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Affiliation(s)
- Sonia Ravanelli
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany
| | - Fabian den Brave
- Department of Molecular Cell Biology, Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Thorsten Hoppe
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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