1
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Bi PY, Killackey SA, Schweizer L, Arnoult D, Philpott DJ, Girardin SE. Cytosolic retention of HtrA2 during mitochondrial protein import stress triggers the DELE1-HRI pathway. Commun Biol 2024; 7:391. [PMID: 38555279 PMCID: PMC10981713 DOI: 10.1038/s42003-024-06107-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 03/25/2024] [Indexed: 04/02/2024] Open
Abstract
Mitochondrial stress inducers such as carbonyl cyanide m-chlorophenyl hydrazone (CCCP) and oligomycin trigger the DELE1-HRI branch of the integrated stress response (ISR) pathway. Previous studies performed using epitope-tagged DELE1 showed that these stresses induced the cleavage of DELE1 to DELE1-S, which stimulates HRI. Here, we report that mitochondrial protein import stress (MPIS) is an overarching stress that triggers the DELE1-HRI pathway, and that endogenous DELE1 could be cleaved into two forms, DELE1-S and DELE1-VS, the latter accumulating only upon non-depolarizing MPIS. Surprisingly, while the mitochondrial protease OMA1 was crucial for DELE1 cleavage in HeLa cells, it was dispensable in HEK293T cells, suggesting that multiple proteases may be involved in DELE1 cleavage. In support, we identified a role for the mitochondrial protease, HtrA2, in mediating DELE1 cleavage into DELE1-VS, and showed that a Parkinson's disease (PD)-associated HtrA2 mutant displayed reduced DELE1 processing ability, suggesting a novel mechanism linking PD pathogenesis to mitochondrial stress. Our data further suggest that DELE1 is likely cleaved into DELE1-S in the cytosol, while the DELE1-VS form might be generated during halted translocation into mitochondria. Together, this study identifies MPIS as the overarching stress detected by DELE1 and identifies a novel role for HtrA2 in DELE1 processing.
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Affiliation(s)
- Paul Y Bi
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Samuel A Killackey
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Linus Schweizer
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Damien Arnoult
- INSERM U1197, Hôpital Paul Brousse, Bâtiment Lavoisier, Villejuif, Cedex, 94807, France
| | - Dana J Philpott
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada
- Department of Immunology, University of Toronto, Toronto, ON, M5S 1A8, Canada
| | - Stephen E Girardin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
- Department of Immunology, University of Toronto, Toronto, ON, M5S 1A8, Canada.
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2
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Lv W, Liang L, Liu D, Li C, Jia L, Jin Y. Aquaporin 1 Facilitates Ferroptosis, M1 Polarization, Mitochondrial Dysfunction, and Autophagy Damage on Lipopolysaccharide-Induced Macrophage Through Down-Regulation of P53 Signaling Pathway. DNA Cell Biol 2023; 42:456-480. [PMID: 37379471 PMCID: PMC10457627 DOI: 10.1089/dna.2023.0016] [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: 01/20/2023] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 06/30/2023] Open
Abstract
This study was designed to investigate the role of aquaporin 1 (AQP1) in ferroptosis, macrophage polarization, mitochondrial dysfunction, and impaired autophagy of lipopolysaccharide (LPS)-stimulated RAW264.7 cells and explored the underlying mechanisms. Si-AQP1-mediated AQP1 silencing RAW264.7 cells was constructed. Si-P53-mediated P53 silencing or pcDNA-P53 overexpression RAW264.7 cells was constructed. Assays of ATP, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and Mitochondrial membrane potential (JC-1) staining were performed to evaluate mitochondrial biological function. Assays of flow cytometry, reactive oxygen species (ROS) staining, western blot (WB), RT-qPCR, malondialdehyde (MDA), glutathione (GSH), and total superoxide dismutase (SOD) were performed to detect cell ferroptosis, macrophage polarization, and impaired autophagy. The involvement of the P53 pathway was revealed by WB. The results showed that LPS (30 μg/mL) could induce ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage in RAW264.7 cells. Meanwhile, the expression of AQP1 was increased and the expression of P53 was decreased. In addition, Pifithrin-α (PIF; 15 μM), a P53 inhibitor, significantly aggravated ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage as well as up-regulation of AQP1 protein expression in LPS-induced RAW264.7 cells. Interestingly, this phenomenon was markedly alleviated by Kevetrin hydrochloride (70 μM), a P53 agonist. Mechanistically, silencing AQP1 significantly alleviated ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy damage by up-regulating the expression of P53 in LPS-stimulated RAW264.7 cells. Indeed, inhibition of P53 expression by PIF treatment dramatically reversed this effect on the basis of LPS+si-AQP1. Therefore, we concluded for the first time that AQP1 can promote ferroptosis, M1 polarization, mitochondrial dysfunction, and autophagy impairment by inhibiting the expression of P53 in LPS-stimulated RAW264.7 cells, and AQP1 or P53 may be considered as a crucial determiner that can regulate the biological behavior of RAW264.7 cells stimulated by LPS.
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Affiliation(s)
- Wuyang Lv
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Lei Liang
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Dongyang Liu
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Cuicui Li
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Liao Jia
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yingyu Jin
- Department of Clinical Laboratory, The First Affiliated Hospital of Harbin Medical University, Harbin, China
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3
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Chen S, Allen G, Panasenko OO, Collart MA. Not4-dependent targeting of MMF1 mRNA to mitochondria limits its expression via ribosome pausing, Egd1 ubiquitination, Caf130, no-go-decay and autophagy. Nucleic Acids Res 2023; 51:5022-5039. [PMID: 37094076 PMCID: PMC10250226 DOI: 10.1093/nar/gkad299] [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: 08/29/2022] [Accepted: 04/11/2023] [Indexed: 04/26/2023] Open
Abstract
The Ccr4-Not complex is a conserved multi protein complex with diverse roles in the mRNA life cycle. Recently we determined that the Not1 and Not4 subunits of Ccr4-Not inversely regulate mRNA solubility and thereby impact dynamics of co-translation events. One mRNA whose solubility is limited by Not4 is MMF1 encoding a mitochondrial matrix protein. In this work we uncover a mechanism that limits MMF1 overexpression and depends upon its co-translational targeting to the mitochondria. We have named this mechanism Mito-ENCay. This mechanism relies on Not4 promoting ribosome pausing during MMF1 translation, and hence the co-translational docking of the MMF1 mRNA to mitochondria via the mitochondrial targeting sequence of the Mmf1 nascent chain, the Egd1 chaperone, the Om14 mitochondrial outer membrane protein and the co-translational import machinery. Besides co-translational Mitochondrial targeting, Mito-ENCay depends upon Egd1 ubiquitination by Not4, the Caf130 subunit of the Ccr4-Not complex, the mitochondrial outer membrane protein Cis1, autophagy and no-go-decay.
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Affiliation(s)
- Siyu Chen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - George Allen
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - Olesya O Panasenko
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
| | - Martine A Collart
- Department of Microbiology and Molecular Medicine, Faculty of Medicine, University of Geneva, Institute of Genetics and Genomics of Geneva, Geneva, Switzerland
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4
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Ulaganathan T, Perales S, Mani S, Baskhairoun BA, Rajasingh J. Pathological implications of cellular stress in cardiovascular diseases. Int J Biochem Cell Biol 2023; 158:106397. [PMID: 36931385 PMCID: PMC10124590 DOI: 10.1016/j.biocel.2023.106397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 03/17/2023]
Abstract
Cellular stress has been a key factor in the development of cardiovascular diseases. Major types of cellular stress such as mitochondrial stress, endoplasmic reticulum stress, hypoxia, and replicative stress have been implicated in clinical complications of cardiac patients. The heart is the central regulator of the body by supplying oxygenated blood throughout the system. Impairment of cellular function could lead to heart failure, myocardial infarction, ischemia, and even stroke. Understanding the effect of these distinct types of cellular stress on cardiac function is crucial for the scientific community to understand and develop novel therapeutic approaches. This review will comprehensively explain the different mechanisms of cellular stress and the most recent findings related to stress-induced cardiac dysfunction.
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Affiliation(s)
- Thennavan Ulaganathan
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Biotechnology, SRM Institute of Science and Technology, kattankulathur, Tamilnadu, 603203, India
| | - Selene Perales
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Saiprahalad Mani
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Biotechnology, SRM Institute of Science and Technology, kattankulathur, Tamilnadu, 603203, India
| | - Boula A Baskhairoun
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Johnson Rajasingh
- Department of Bioscience Research, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Medicine-Cardiology, University of Tennessee Health Science Center, Memphis, TN, USA; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN, USA.
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5
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Nowicka U, Chroscicki P, Stroobants K, Sladowska M, Turek M, Uszczynska-Ratajczak B, Kundra R, Goral T, Perni M, Dobson CM, Vendruscolo M, Chacinska A. Cytosolic aggregation of mitochondrial proteins disrupts cellular homeostasis by stimulating the aggregation of other proteins. eLife 2021; 10:65484. [PMID: 34292154 PMCID: PMC8457837 DOI: 10.7554/elife.65484] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 07/19/2021] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are organelles with their own genomes, but they rely on the import of nuclear-encoded proteins that are translated by cytosolic ribosomes. Therefore, it is important to understand whether failures in the mitochondrial uptake of these nuclear-encoded proteins can cause proteotoxic stress and identify response mechanisms that may counteract it. Here, we report that upon impairments in mitochondrial protein import, high-risk precursor and immature forms of mitochondrial proteins form aberrant deposits in the cytosol. These deposits then cause further cytosolic accumulation and consequently aggregation of other mitochondrial proteins and disease-related proteins, including α-synuclein and amyloid β. This aggregation triggers a cytosolic protein homeostasis imbalance that is accompanied by specific molecular chaperone responses at both the transcriptomic and protein levels. Altogether, our results provide evidence that mitochondrial dysfunction, specifically protein import defects, contributes to impairments in protein homeostasis, thus revealing a possible molecular mechanism by which mitochondria are involved in neurodegenerative diseases.
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Affiliation(s)
- Urszula Nowicka
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Piotr Chroscicki
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Karen Stroobants
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Maria Sladowska
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Michal Turek
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | | | - Rishika Kundra
- Department of Chemistry, University of Cambridge, Cambridge, United Kingdom
| | - Tomasz Goral
- Centre of New Technologies, University of Warsaw, Warsaw, Poland
| | - Michele Perni
- Chemistry, University of Cambridge, Cambridge, United Kingdom
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6
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Eisele F, Eisele-Bürger AM, Hao X, Berglund LL, Höög JL, Liu B, Nyström T. An Hsp90 co-chaperone links protein folding and degradation and is part of a conserved protein quality control. Cell Rep 2021; 35:109328. [PMID: 34192536 DOI: 10.1016/j.celrep.2021.109328] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 11/30/2020] [Accepted: 06/09/2021] [Indexed: 10/21/2022] Open
Abstract
In this paper, we show that the essential Hsp90 co-chaperone Sgt1 is a member of a general protein quality control network that links folding and degradation through its participation in the degradation of misfolded proteins both in the cytosol and the endoplasmic reticulum (ER). Sgt1-dependent protein degradation acts in a parallel pathway to the ubiquitin ligase (E3) and ubiquitin chain elongase (E4), Hul5, and overproduction of Hul5 partly suppresses defects in cells with reduced Sgt1 activity. Upon proteostatic stress, Sgt1 accumulates transiently, in an Hsp90- and proteasome-dependent manner, with quality control sites (Q-bodies) of both yeast and human cells that co-localize with Vps13, a protein that creates organelle contact sites. Misfolding disease proteins, such as synphilin-1 involved in Parkinson's disease, are also sequestered to these compartments and require Sgt1 for their clearance.
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Affiliation(s)
- Frederik Eisele
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Medicinaregatan 7A, 413 90 Gothenburg, Sweden.
| | - Anna Maria Eisele-Bürger
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Medicinaregatan 7A, 413 90 Gothenburg, Sweden; Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, 75007 Uppsala, Sweden
| | - Xinxin Hao
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Medicinaregatan 7A, 413 90 Gothenburg, Sweden
| | - Lisa Larsson Berglund
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Medicinaregatan 7A, 413 90 Gothenburg, Sweden; Department of Chemistry & Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90 Gothenburg, Sweden
| | - Johanna L Höög
- Department of Chemistry & Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90 Gothenburg, Sweden
| | - Beidong Liu
- Department of Chemistry & Molecular Biology, University of Gothenburg, Medicinaregatan 9 C, 413 90 Gothenburg, Sweden
| | - Thomas Nyström
- Institute for Biomedicine, Sahlgrenska Academy, Centre for Ageing and Health - AgeCap, University of Gothenburg, Medicinaregatan 7A, 413 90 Gothenburg, Sweden.
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7
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Liao PC, Wolken DMA, Serrano E, Srivastava P, Pon LA. Mitochondria-Associated Degradation Pathway (MAD) Function beyond the Outer Membrane. Cell Rep 2021; 32:107902. [PMID: 32668258 PMCID: PMC7391283 DOI: 10.1016/j.celrep.2020.107902] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 01/07/2020] [Accepted: 06/23/2020] [Indexed: 12/01/2022] Open
Abstract
The mitochondria-associated degradation pathway (MAD) mediates ubiquitination and degradation of mitochondrial outer membrane (MOM) proteins by the proteasome. We find that the MAD, but not other quality-control pathways including macroautophagy, mitophagy, or mitochondrial chaperones and proteases, is critical for yeast cellular fitness under conditions of paraquat (PQ)-induced oxidative stress in mitochondria. Specifically, inhibition of the MAD increases PQ-induced defects in growth and mitochondrial quality and decreases chronological lifespan. We use mass spectrometry analysis to identify possible MAD substrates as mitochondrial proteins that exhibit increased ubiquitination in response to PQ treatment and inhibition of the MAD. We identify candidate substrates in the mitochondrial matrix and inner membrane and confirm that two matrix proteins are MAD substrates. Our studies reveal a broader function for the MAD in mitochondrial protein surveillance beyond the MOM and a major role for the MAD in cellular and mitochondrial fitness in response to chronic, low-level oxidative stress in mitochondria.
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Affiliation(s)
- Pin-Chao Liao
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | | | - Edith Serrano
- Department of Chemistry, Barnard College, Columbia University, New York, NY 10027, USA
| | - Pallavi Srivastava
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G1H9, Canada
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.
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8
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Camougrand N, Vigié P, Gonzalez C, Manon S, Bhatia-Kiššová I. The yeast mitophagy receptor Atg32 is ubiquitinated and degraded by the proteasome. PLoS One 2020; 15:e0241576. [PMID: 33362225 PMCID: PMC7757876 DOI: 10.1371/journal.pone.0241576] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 10/18/2020] [Indexed: 12/21/2022] Open
Abstract
Mitophagy, the process that degrades mitochondria selectively through autophagy, is involved in the quality control of mitochondria in cells grown under respiratory conditions. In yeast, the presence of the Atg32 protein on the outer mitochondrial membrane allows for the recognition and targeting of superfluous or damaged mitochondria for degradation. Post-translational modifications such as phosphorylation are crucial for the execution of mitophagy. In our study we monitor the stability of Atg32 protein in the yeast S. cerevisiae and show that Atg32 is degraded under normal growth conditions, upon starvation or rapamycin treatment. The Atg32 turnover can be prevented by inhibition of the proteasome activity, suggesting that Atg32 is also ubiquitinated. Mass spectrometry analysis of purified Atg32 protein revealed that at least lysine residue in position 282 is ubiquitinated. Interestingly, the replacement of lysine 282 with alanine impaired Atg32 degradation only partially in the course of cell growth, suggesting that additional lysine residues on Atg32 might also be ubiquitinated. Our results provide the foundation to further elucidate the physiological significance of Atg32 turnover and the interplay between mitophagy and the proteasome.
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Affiliation(s)
- Nadine Camougrand
- CNRS and Université de Bordeaux, IBGC, UMR5095, Bordeaux, France
- * E-mail:
| | - Pierre Vigié
- CNRS and Université de Bordeaux, IBGC, UMR5095, Bordeaux, France
| | - Cécile Gonzalez
- CNRS and Université de Bordeaux, IBGC, UMR5095, Bordeaux, France
| | - Stéphen Manon
- CNRS and Université de Bordeaux, IBGC, UMR5095, Bordeaux, France
| | - Ingrid Bhatia-Kiššová
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovak Republic
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9
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Alsayyah C, Ozturk O, Cavellini L, Belgareh-Touzé N, Cohen MM. The regulation of mitochondrial homeostasis by the ubiquitin proteasome system. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148302. [PMID: 32861697 DOI: 10.1016/j.bbabio.2020.148302] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/05/2020] [Accepted: 08/24/2020] [Indexed: 02/07/2023]
Abstract
From mitochondrial quality control pathways to the regulation of specific functions, the Ubiquitin Proteasome System (UPS) could be compared to a Swiss knife without which mitochondria could not maintain its integrity in the cell. Here, we review the mechanisms that the UPS employs to regulate mitochondrial function and efficiency. For this purpose, we depict how Ubiquitin and the Proteasome participate in diverse quality control pathways that safeguard entry into the mitochondrial compartment. A focus is then achieved on the UPS-mediated control of the yeast mitofusin Fzo1 which provides insights into the complex regulation of this particular protein in mitochondrial fusion. We ultimately dissect the mechanisms by which the UPS controls the degradation of mitochondria by autophagy in both mammalian and yeast systems. This organization should offer a useful overview of this abundant but fascinating literature on the crosstalks between mitochondria and the UPS.
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Affiliation(s)
- Cynthia Alsayyah
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Oznur Ozturk
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Laetitia Cavellini
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Naïma Belgareh-Touzé
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France
| | - Mickael M Cohen
- Sorbonne Université, CNRS, UMR8226, Institut de Biologie Physico-Chimique, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, F-75005 Paris, France.
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10
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Wang N, Zhu P, Huang R, Wang C, Sun L, Lan B, He Y, Zhao H, Gao Y. PINK1: The guard of mitochondria. Life Sci 2020; 259:118247. [PMID: 32805222 DOI: 10.1016/j.lfs.2020.118247] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/26/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022]
Abstract
PTEN-induced putative kinase 1 (PINK1) performs many important functions in cells and has been highlighted for its role in early-onset Parkinson's disease. In recent years, an increasing number of studies have revealed the involvement of PINK1 in regulation of a variety of cell physiological and pathophysiological processes, of which regulation of mitochondrial function remains the most prominent. As the "energy factory" of cells, mitochondria provide energy support for various cellular activities. Changes in mitochondrial function often have a fundamental and global impact on cellular activities. Moreover, mitochondrial dysfunction has been implicated in many diseases, especially those related to aging. Thus, a comprehensive study of PINK1 will help us better understand the various cell physiological and pathophysiological processes in which PINK1 is involved, including a variety of mitochondria-related diseases such as Parkinson's disease. This article will review the structural characteristics and expression regulation of PINK1, as well as its unique role in mitochondrial quality control (MQC) systems.
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Affiliation(s)
- Nan Wang
- China-Japan Union Hospital, Jilin University, China
| | - Peining Zhu
- China-Japan Union Hospital, Jilin University, China
| | | | - Chong Wang
- China-Japan Union Hospital, Jilin University, China
| | - Liankun Sun
- Key Laboratory of Pathobiology, Ministry of Education, Department of Pathophysiology, College of Basic Medical Sciences, Jilin University, China
| | - Beiwu Lan
- China-Japan Union Hospital, Jilin University, China
| | - Yichun He
- China-Japan Union Hospital, Jilin University, China
| | | | - Yufei Gao
- China-Japan Union Hospital, Jilin University, China.
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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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12
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PI3K/Akt pathway-mediated HO-1 induction regulates mitochondrial quality control and attenuates endotoxin-induced acute lung injury. J Transl Med 2019; 99:1795-1809. [PMID: 31570770 DOI: 10.1038/s41374-019-0286-x] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 04/26/2019] [Accepted: 05/24/2019] [Indexed: 12/31/2022] Open
Abstract
Sepsis-related acute lung injury (ALI) remains a major cause of mortality in critically ill patients and lacks specific therapy. Mitochondrial dysfunction is involved in the progression of septic lung injury. Mitochondrial dynamics, mitophagy, and biogenesis converge to constitute the assiduous quality control of mitochondria (MQC). Heme oxygenase-1 (HO-1) protects against sepsis-induced ALI through the modulation of mitochondrial dynamics. However, the causal relationship between HO-1 and the general processes of MQC, and their associated cellular pathways in sepsis-related ALI remain ill-defined. Herein, lipopolysaccharide (LPS)-induced ALI in Sprague-Dawley rats together with LPS-induced oxidative injury in RAW264.7 macrophages were used to investigate whether the PI3K/Akt pathway-mediated induction of HO-1 preserves MQC and alleviates septic lung injury. After pretreatment with hemin, a potent inducer of HO-1, LPS-induced cell apoptosis, enhanced mitochondrial fragmentation, and mitochondrial membrane potential damage were significantly reduced in macrophages. In rats, these effects were accompanied by a higher survival rate, less damage to lung tissue, a 28.5% elevation in lung mitochondria MnSOD activity, and a 39.2% increase in respiratory control ratios. Concomitantly, HO-1 induction preserved the dynamic process of mitochondrial fusion/fission (Mfn2, OPA1, Drp1), promoted mitochondrial biogenesis (NRF1, PGC1α, Tfam), and facilitated the key mediators of mitochondrial mitophagy (Parkin, PINK1) at mRNA and protein levels. Notably, LY294002, a PI3K inhibitor, or knockdown of PI3K by small interfering RNA significantly suppressed Akt phosphorylation, attenuated HO-1 induction, and further reversed these beneficial effects evoked by hemin pretreatment in RAW264.7 cells or rats received LPS, indicating a direct involvement of PI3K/Akt pathway. Taken together, our results indicated that HO-1 activation, through PI3K/Akt pathway, plays a critical role in protecting lung from oxidative injury in the setting of sepsis by regulating MQC. HO-1 may therefore be a therapeutic target for the prevention sepsis-related lung injury.
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Mitophagy, Mitochondrial Dynamics, and Homeostasis in Cardiovascular Aging. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9825061. [PMID: 31781358 PMCID: PMC6875274 DOI: 10.1155/2019/9825061] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 09/13/2019] [Indexed: 12/19/2022]
Abstract
Biological aging is an inevitable and independent risk factor for a wide array of chronic diseases including cardiovascular and metabolic diseases. Ample evidence has established a pivotal role for interrupted mitochondrial homeostasis in the onset and development of aging-related cardiovascular anomalies. A number of culprit factors have been suggested in aging-associated mitochondrial anomalies including oxidative stress, lipid toxicity, telomere shortening, metabolic disturbance, and DNA damage, with recent findings revealing a likely role for compromised mitochondrial dynamics and mitochondrial quality control machinery such as autophagy. Mitochondria undergo consistent fusion and fission, which are crucial for mitochondrial homeostasis and energy adaptation. Autophagy, in particular, mitochondria-selective autophagy, namely, mitophagy, refers to a highly conservative cellular process to degrade and clear long-lived or damaged cellular organelles including mitochondria, the function of which gradually deteriorates with increased age. Mitochondrial homeostasis could be achieved through a cascade of independent but closely related processes including fusion, fission, mitophagy, and mitochondrial biogenesis. With improved health care and increased human longevity, the ever-rising aging society has imposed a high cardiovascular disease prevalence. It is thus imperative to understand the role of mitochondrial homeostasis in the regulation of lifespan and healthspan. Targeting mitochondrial homeostasis should offer promising novel therapeutic strategies against aging-related complications, particularly cardiovascular diseases.
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14
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Ling Q, Broad W, Trösch R, Töpel M, Demiral Sert T, Lymperopoulos P, Baldwin A, Jarvis RP. Ubiquitin-dependent chloroplast-associated protein degradation in plants. Science 2019; 363:363/6429/eaav4467. [PMID: 30792274 DOI: 10.1126/science.aav4467] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/15/2019] [Indexed: 12/11/2022]
Abstract
Chloroplasts contain thousands of nucleus-encoded proteins that are imported from the cytosol by translocases in the chloroplast envelope membranes. Proteolytic regulation of the translocases is critically important, but little is known about the underlying mechanisms. We applied forward genetics and proteomics in Arabidopsis to identify factors required for chloroplast outer envelope membrane (OEM) protein degradation. We identified SP2, an Omp85-type β-barrel channel of the OEM, and CDC48, a cytosolic AAA+ (ATPase associated with diverse cellular activities) chaperone. Both proteins acted in the same pathway as the ubiquitin E3 ligase SP1, which regulates OEM translocase components. SP2 and CDC48 cooperated to bring about retrotranslocation of ubiquitinated substrates from the OEM (fulfilling conductance and motor functions, respectively), enabling degradation of the substrates by the 26S proteasome in the cytosol. Such chloroplast-associated protein degradation (CHLORAD) is vital for organellar functions and plant development.
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Affiliation(s)
- Qihua Ling
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - William Broad
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Raphael Trösch
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Mats Töpel
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | | | - Amy Baldwin
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | - R Paul Jarvis
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK. .,Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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15
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Soares TR, Reis SD, Pinho BR, Duchen MR, Oliveira JMA. Targeting the proteostasis network in Huntington's disease. Ageing Res Rev 2019; 49:92-103. [PMID: 30502498 PMCID: PMC6320389 DOI: 10.1016/j.arr.2018.11.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 11/19/2018] [Accepted: 11/26/2018] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a polyglutamine expansion mutation in the huntingtin protein. Expansions above 40 polyglutamine repeats are invariably fatal, following a symptomatic period characterised by choreiform movements, behavioural abnormalities, and cognitive decline. While mutant huntingtin (mHtt) is widely expressed from early life, most patients with HD present in mid-adulthood, highlighting the role of ageing in disease pathogenesis. mHtt undergoes proteolytic cleavage, misfolding, accumulation, and aggregation into inclusion bodies. The emerging model of HD pathogenesis proposes that the chronic production of misfolded mHtt overwhelms the chaperone machinery, diverting other misfolded clients to the proteasome and the autophagy pathways, ultimately leading to a global collapse of the proteostasis network. Multiple converging hypotheses also implicate ageing and its impact in the dysfunction of organelles as additional contributing factors to the collapse of proteostasis in HD. In particular, mitochondrial function is required to sustain the activity of ATP-dependent chaperones and proteolytic machinery. Recent studies elucidating mitochondria-endoplasmic reticulum interactions and uncovering a dedicated proteostasis machinery in mitochondria, suggest that mitochondria play a more active role in the maintenance of cellular proteostasis than previously thought. The enhancement of cytosolic proteostasis pathways shows promise for HD treatment, protecting cells from the detrimental effects of mHtt accumulation. In this review, we consider how mHtt and its post translational modifications interfere with protein quality control pathways, and how the pharmacological and genetic modulation of components of the proteostasis network impact disease phenotypes in cellular and in vivo HD models.
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Affiliation(s)
- Tânia R Soares
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK
| | - Sara D Reis
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Brígida R Pinho
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal
| | - Michael R Duchen
- Department of Cell and Developmental Biology, University College London, London, WC1E 6BT, UK; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK
| | - Jorge M A Oliveira
- REQUIMTE/LAQV, Department of Drug Sciences, Pharmacology Lab, Faculty of Pharmacy, University of Porto, 4050-313, Porto, Portugal; Consortium for Mitochondrial Research (CfMR), University College London, Gower Street, WC1E 6BT, London, UK.
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16
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Tao YX, Conn PM. Pharmacoperones as Novel Therapeutics for Diverse Protein Conformational Diseases. Physiol Rev 2018; 98:697-725. [PMID: 29442594 DOI: 10.1152/physrev.00029.2016] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
After synthesis, proteins are folded into their native conformations aided by molecular chaperones. Dysfunction in folding caused by genetic mutations in numerous genes causes protein conformational diseases. Membrane proteins are more prone to misfolding due to their more intricate folding than soluble proteins. Misfolded proteins are detected by the cellular quality control systems, especially in the endoplasmic reticulum, and proteins may be retained there for eventual degradation by the ubiquitin-proteasome system or through autophagy. Some misfolded proteins aggregate, leading to pathologies in numerous neurological diseases. In vitro, modulating mutant protein folding by altering molecular chaperone expression can ameliorate some misfolding. Some small molecules known as chemical chaperones also correct mutant protein misfolding in vitro and in vivo. However, due to their lack of specificity, their potential as therapeutics is limited. Another class of compounds, known as pharmacological chaperones (pharmacoperones), binds with high specificity to misfolded proteins, either as enzyme substrates or receptor ligands, leading to decreased folding energy barriers and correction of the misfolding. Because many of the misfolded proteins are misrouted but do not have defects in function per se, pharmacoperones have promising potential in advancing to the clinic as therapeutics, since correcting routing may ameliorate the underlying mechanism of disease. This review will comprehensively summarize this exciting area of research, surveying the literature from in vitro studies in cell lines to transgenic animal models and clinical trials in several protein misfolding diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
| | - P Michael Conn
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
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17
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Wei Z, Su W, Lou H, Duan S, Chen G. Trafficking pathway between plasma membrane and mitochondria via clathrin-mediated endocytosis. J Mol Cell Biol 2018; 10:539-548. [DOI: 10.1093/jmcb/mjy060] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 10/31/2018] [Indexed: 12/21/2022] Open
Affiliation(s)
- Zhongya Wei
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Wenfeng Su
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Huifang Lou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Shumin Duan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Gang Chen
- Key Laboratory of Neuroregeneration of Jiangsu Province and the Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Department of Anesthesiology, Affiliated Hospital of Nantong University, Nantong, China
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18
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Che Y, Wang ZP, Yuan Y, Zhang N, Jin YG, Wan CX, Tang QZ. Role of autophagy in a model of obesity: A long‑term high fat diet induces cardiac dysfunction. Mol Med Rep 2018; 18:3251-3261. [PMID: 30066870 PMCID: PMC6102660 DOI: 10.3892/mmr.2018.9301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/19/2018] [Indexed: 12/13/2022] Open
Abstract
Obesity may induce end-organ damage through metabolic syndrome, and autophagy serves a vital role in the pathogenesis of metabolic syndrome. The purpose of the present study was to define the roles of autophagy and mitophagy in high fat diet (HFD)-induced cardiomyopathy. Male, 8 week-old C57BL/6 mice were fed either a HFD (60% kcal) or a diet of normal chow (NC; 10% kcal) for 42 weeks. Glucose tolerance tests were performed during the feeding regimes. Blood samples were collected for assaying serum triglyceride with the glycerol-3-phosphate oxidase phenol and aminophenazone (PAP) method and total cholesterol was tested with the cholesterol oxidase-PAP method. Myocardial function was assessed using echocardiography and hemodynamic analyses. Western blot analysis was employed to evaluate endoplasmic reticulum stress (ERS), autophagy and mitochondrial function. Electron microscopy was used to assess the number of lipid droplets and the degree of autophagy within the myocardium. The body weight and adipose tissue weight of mice fed the HFD were increased compared with the NC mice. The serum levels of blood glucose, total cholesterol and triglyceride were significantly increased following 42 weeks of HFD feeding. The results of the glucose tolerance tests additionally demonstrated metabolic dysregulation in HFD mice. In addition, HFD mice exhibited hemodynamic and echocardiographic evidence of impaired diastolic and systolic function, including alterations in the cardiac output, end-diastolic pressure, end-diastolic volume and left ventricular relaxation time constant (tau) following HFD intake. Furthermore, a HFD resulted in increased ERS, and a downregulation of the autophagy and mitophagy level. The present study investigated cardiac function in obese HFD-fed mice. These results aid the pursuit of novel therapeutic targets to combat obesity-associated cardiomyopathy.
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Affiliation(s)
- Yan Che
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Zhao-Peng Wang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Yuan Yuan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Ning Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Ya-Ge Jin
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Chun-Xia Wan
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
| | - Qi-Zhu Tang
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, P.R. China
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The Ubiquitin Ligase (E3) Psh1p Is Required for Proper Segregation of both Centromeric and Two-Micron Plasmids in Saccharomyces cerevisiae. G3-GENES GENOMES GENETICS 2017; 7:3731-3743. [PMID: 28928274 PMCID: PMC5677152 DOI: 10.1534/g3.117.300227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Protein degradation by the ubiquitin-proteasome system is essential to many processes. We sought to assess its involvement in the turnover of mitochondrial proteins in Saccharomyces cerevisiae. We find that deletion of a specific ubiquitin ligase (E3), Psh1p, increases the abundance of a temperature-sensitive mitochondrial protein, mia40-4pHA, when it is expressed from a centromeric plasmid. Deletion of Psh1p unexpectedly elevates the levels of other proteins expressed from centromeric plasmids. Loss of Psh1p does not increase the rate of turnover of mia40-4pHA, affect total protein synthesis, or increase the protein levels of chromosomal genes. Instead, psh1Δ appears to increase the incidence of missegregation of centromeric plasmids relative to their normal 1:1 segregation. After generations of growth with selection for the plasmid, ongoing missegregation would lead to elevated plasmid DNA, mRNA, and protein, all of which we observe in psh1Δ cells. The only known substrate of Psh1p is the centromeric histone H3 variant Cse4p, which is targeted for proteasomal degradation after ubiquitination by Psh1p. However, Cse4p overexpression alone does not phenocopy psh1Δ in increasing plasmid DNA and protein levels. Instead, elevation of Cse4p leads to an apparent increase in 1:0 plasmid segregation events. Further, 2 μm high-copy yeast plasmids also missegregate in psh1Δ, but not when Cse4p alone is overexpressed. These findings demonstrate that Psh1p is required for the faithful inheritance of both centromeric and 2 μm plasmids. Moreover, the effects that loss of Psh1p has on plasmid segregation cannot be accounted for by increased levels of Cse4p.
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20
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Schorr S, van der Laan M. Integrative functions of the mitochondrial contact site and cristae organizing system. Semin Cell Dev Biol 2017; 76:191-200. [PMID: 28923515 DOI: 10.1016/j.semcdb.2017.09.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 12/23/2022]
Abstract
Mitochondria are complex double-membrane-bound organelles of eukaryotic cells that function as energy-converting powerhouses, metabolic factories and signaling centers. The outer membrane controls the exchange of material and information with other cellular compartments. The inner membrane provides an extended, highly folded surface for selective transport and energy-coupling reactions. It can be divided into an inner boundary membrane and tubular or lamellar cristae membranes that accommodate the oxidative phosphorylation units. Outer membrane, inner boundary membrane and cristae come together at crista junctions, where the mitochondrial contact site and cristae organizing system (MICOS) acts as a membrane-shaping and -connecting scaffold. This peculiar architecture is of pivotal importance for multiple mitochondrial functions. Many elaborate studies in the past years have shed light on the subunit composition and organization of MICOS. In this review article, we summarize these insights and then move on to discuss exciting recent discoveries on the integrative functions of MICOS. Multi-faceted connections to other major players of mitochondrial biogenesis and physiology, like the protein import machineries, the oxidative phosphorylation system, carrier proteins and phospholipid biosynthesis enzymes, are currently emerging. Therefore, we propose that MICOS acts as a central hub in mitochondrial membrane architecture and functionality.
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Affiliation(s)
- Stefan Schorr
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University, School of Medicine, 66421, Homburg, Germany
| | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University, School of Medicine, 66421, Homburg, Germany.
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21
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Chaturvedi D, Mahalakshmi R. Transmembrane β-barrels: Evolution, folding and energetics. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2467-2482. [PMID: 28943271 DOI: 10.1016/j.bbamem.2017.09.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022]
Abstract
The biogenesis of transmembrane β-barrels (outer membrane proteins, or OMPs) is an elaborate multistep orchestration of the nascent polypeptide with translocases, barrel assembly machinery, and helper chaperone proteins. Several theories exist that describe the mechanism of chaperone-assisted OMP assembly in vivo and unassisted (spontaneous) folding in vitro. Structurally, OMPs of bacterial origin possess even-numbered strands, while mitochondrial β-barrels are even- and odd-stranded. Several underlying similarities between prokaryotic and eukaryotic β-barrels and their folding machinery are known; yet, the link in their evolutionary origin is unclear. While OMPs exhibit diversity in sequence and function, they share similar biophysical attributes and structure. Similarly, it is important to understand the intricate OMP assembly mechanism, particularly in eukaryotic β-barrels that have evolved to perform more complex functions. Here, we deliberate known facets of β-barrel evolution, folding, and stability, and attempt to highlight outstanding questions in β-barrel biogenesis and proteostasis.
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Affiliation(s)
- Deepti Chaturvedi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
| | - Radhakrishnan Mahalakshmi
- Molecular Biophysics Laboratory, Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal 462066, India.
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22
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Krüger V, Becker T, Becker L, Montilla-Martinez M, Ellenrieder L, Vögtle FN, Meyer HE, Ryan MT, Wiedemann N, Warscheid B, Pfanner N, Wagner R, Meisinger C. Identification of new channels by systematic analysis of the mitochondrial outer membrane. J Cell Biol 2017; 216:3485-3495. [PMID: 28916712 PMCID: PMC5674900 DOI: 10.1083/jcb.201706043] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 08/03/2017] [Accepted: 08/22/2017] [Indexed: 02/08/2023] Open
Abstract
Channels in the mitochondrial outer membrane exchange metabolites, ions, and proteins with the rest of the cell. Kruger et al. identify several new types of channel and suggest that the outer mitochondrial membrane is a more selective molecular sieve with a greater variety of channel-forming proteins than previously appreciated. The mitochondrial outer membrane is essential for communication between mitochondria and the rest of the cell and facilitates the transport of metabolites, ions, and proteins. All mitochondrial outer membrane channels known to date are β-barrel membrane proteins, including the abundant voltage-dependent anion channel and the cation-preferring protein-conducting channels Tom40, Sam50, and Mdm10. We analyzed outer membrane fractions of yeast mitochondria and identified four new channel activities: two anion-preferring channels and two cation-preferring channels. We characterized the cation-preferring channels at the molecular level. The mitochondrial import component Mim1 forms a channel that is predicted to have an α-helical structure for protein import. The short-chain dehydrogenase-related protein Ayr1 forms an NADPH-regulated channel. We conclude that the mitochondrial outer membrane contains a considerably larger variety of channel-forming proteins than assumed thus far. These findings challenge the traditional view of the outer membrane as an unspecific molecular sieve and indicate a higher degree of selectivity and regulation of metabolite fluxes at the mitochondrial boundary.
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Affiliation(s)
- Vivien Krüger
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany.,Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Lars Becker
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany
| | | | - Lars Ellenrieder
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - F-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Helmut E Meyer
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Michael T Ryan
- Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Bettina Warscheid
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.,Institute of Biology II, Biochemistry - Functional Proteomics, Faculty of Biology, University of Freiburg, Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany .,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
| | - Richard Wagner
- Division of Biophysics, School of Biology/Chemistry, University of Osnabrück, Osnabrück, Germany .,Biophysics, Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany
| | - Chris Meisinger
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany
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