1
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Zhan J, Zeher A, Huang R, Tang WK, Jenkins LM, Xia D. Conformations of Bcs1L undergoing ATP hydrolysis suggest a concerted translocation mechanism for folded iron-sulfur protein substrate. Nat Commun 2024; 15:4655. [PMID: 38821922 PMCID: PMC11143374 DOI: 10.1038/s41467-024-49029-y] [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: 10/10/2023] [Accepted: 05/20/2024] [Indexed: 06/02/2024] Open
Abstract
The human AAA-ATPase Bcs1L translocates the fully assembled Rieske iron-sulfur protein (ISP) precursor across the mitochondrial inner membrane, enabling respiratory Complex III assembly. Exactly how the folded substrate is bound to and released from Bcs1L has been unclear, and there has been ongoing debate as to whether subunits of Bcs1L act in sequence or in unison hydrolyzing ATP when moving the protein cargo. Here, we captured Bcs1L conformations by cryo-EM during active ATP hydrolysis in the presence or absence of ISP substrate. In contrast to the threading mechanism widely employed by AAA proteins in substrate translocation, subunits of Bcs1L alternate uniformly between ATP and ADP conformations without detectable intermediates that have different, co-existing nucleotide states, indicating that the subunits act in concert. We further show that the ISP can be trapped by Bcs1 when its subunits are all in the ADP-bound state, which we propose to be released in the apo form.
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Affiliation(s)
- Jingyu Zhan
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Allison Zeher
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- NIH Intramural Cryo-EM Consortium (NICE), Bethesda, MD, USA
| | - Rick Huang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
- NIH Intramural Cryo-EM Consortium (NICE), Bethesda, MD, USA
| | - Wai Kwan Tang
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Lisa M Jenkins
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Di Xia
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
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2
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Zhou Q, Yang Y, Xu Z, Deng K, Zhang Z, Hao J, Li N, Wang Y, Wang Z, Chen H, Yang Y, Xiao F, Zhang X, Gao S, Li Y. ATAD1 inhibits hepatitis C virus infection by removing the viral TA-protein NS5B from mitochondria. EMBO Rep 2023; 24:e56614. [PMID: 37789674 PMCID: PMC10626439 DOI: 10.15252/embr.202256614] [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: 12/06/2022] [Revised: 08/24/2023] [Accepted: 09/01/2023] [Indexed: 10/05/2023] Open
Abstract
ATPase family AAA domain-containing protein 1 (ATAD1) maintains mitochondrial homeostasis by removing mislocalized tail-anchored (TA) proteins from the mitochondrial outer membrane (MOM). Hepatitis C virus (HCV) infection induces mitochondrial fragmentation, and viral NS5B protein is a TA protein. Here, we investigate whether ATAD1 plays a role in regulating HCV infection. We find that HCV infection has no effect on ATAD1 expression, but knockout of ATAD1 significantly enhances HCV infection; this enhancement is suppressed by ATAD1 complementation. NS5B partially localizes to mitochondria, dependent on its transmembrane domain (TMD), and induces mitochondrial fragmentation, which is further enhanced by ATAD1 knockout. ATAD1 interacts with NS5B, dependent on its three internal domains (TMD, pore-loop 1, and pore-loop 2), and induces the proteasomal degradation of NS5B. In addition, we provide evidence that ATAD1 augments the antiviral function of MAVS upon HCV infection. Taken together, we show that the mitochondrial quality control exerted by ATAD1 can be extended to a novel antiviral function through the extraction of the viral TA-protein NS5B from the mitochondrial outer membrane.
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Affiliation(s)
- Qing Zhou
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Technology Center, China Tobacco Henan Industrial Co., LtdZhengzhouChina
- Department of Infectious DiseasesThe Third Affiliated Hospital of Sun Yat‐Sen UniversityGuangzhouChina
| | - Yuhao Yang
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Zhanxue Xu
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Kai Deng
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Guangzhou Eighth People's HospitalGuangzhou Medical UniversityGuangzhouChina
| | - Zhenzhen Zhang
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Jiawei Hao
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Ni Li
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Department of Infectious DiseasesThe Third Affiliated Hospital of Sun Yat‐Sen UniversityGuangzhouChina
| | - Yanling Wang
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Ziwen Wang
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Haihang Chen
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Yang Yang
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
| | - Fei Xiao
- Department of Infectious DiseaseThe Fifth Affiliated Hospital of Sun Yat‐sen UniversityZhuhaiChina
| | - Xiaohong Zhang
- Department of Infectious DiseasesThe Third Affiliated Hospital of Sun Yat‐Sen UniversityGuangzhouChina
| | - Song Gao
- State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Yi‐Ping Li
- Institute of Human Virology, Department of Pathogen Biology and Biosecurity, and Key Laboratory of Tropical Disease Control of Ministry of Education, Zhongshan School of MedicineSun Yat‐sen UniversityGuangzhouChina
- Department of Infectious DiseasesThe Third Affiliated Hospital of Sun Yat‐Sen UniversityGuangzhouChina
- Department of Infectious DiseaseThe Fifth Affiliated Hospital of Sun Yat‐sen UniversityZhuhaiChina
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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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Cho C, Ganser C, Uchihashi T, Kato K, Song JJ. Structure of the human ATAD2 AAA+ histone chaperone reveals mechanism of regulation and inter-subunit communication. Commun Biol 2023; 6:993. [PMID: 37770645 PMCID: PMC10539301 DOI: 10.1038/s42003-023-05373-1] [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: 01/18/2023] [Accepted: 09/19/2023] [Indexed: 09/30/2023] Open
Abstract
ATAD2 is a non-canonical ATP-dependent histone chaperone and a major cancer target. Despite widespread efforts to design drugs targeting the ATAD2 bromodomain, little is known about the overall structural organization and regulation of ATAD2. Here, we present the 3.1 Å cryo-EM structure of human ATAD2 in the ATP state, showing a shallow hexameric spiral that binds a peptide substrate at the central pore. The spiral conformation is locked by an N-terminal linker domain (LD) that wedges between the seam subunits, thus limiting ATP-dependent symmetry breaking of the AAA+ ring. In contrast, structures of the ATAD2-histone H3/H4 complex show the LD undocked from the seam, suggesting that H3/H4 binding unlocks the AAA+ spiral by allosterically releasing the LD. These findings, together with the discovery of an inter-subunit signaling mechanism, reveal a unique regulatory mechanism for ATAD2 and lay the foundation for developing new ATAD2 inhibitors.
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Affiliation(s)
- Carol Cho
- Department of Biological Sciences, KAIST Stem Cell Center, Basic Science 4.0 Institute, and KI for BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
| | - Christian Ganser
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Takayuki Uchihashi
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
- Department of Physics and Institute for Glyco-core Research (iGCORE), Nagoya University, Chikusa-ku, Furo-cho, Nagoya, Aichi, 464-8602, Japan
| | - Koichi Kato
- Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
- Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya, Aichi, 467-8603, Japan
- Institute for Molecular Science (IMS), National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi, 444-8787, Japan
| | - Ji-Joon Song
- Department of Biological Sciences, KAIST Stem Cell Center, Basic Science 4.0 Institute, and KI for BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Korea.
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5
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Rüttermann M, Koci M, Lill P, Geladas ED, Kaschani F, Klink BU, Erdmann R, Gatsogiannis C. Structure of the peroxisomal Pex1/Pex6 ATPase complex bound to a substrate. Nat Commun 2023; 14:5942. [PMID: 37741838 PMCID: PMC10518020 DOI: 10.1038/s41467-023-41640-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 09/12/2023] [Indexed: 09/25/2023] Open
Abstract
The double-ring AAA+ ATPase Pex1/Pex6 is required for peroxisomal receptor recycling and is essential for peroxisome formation. Pex1/Pex6 mutations cause severe peroxisome associated developmental disorders. Despite its pathophysiological importance, mechanistic details of the heterohexamer are not yet available. Here, we report cryoEM structures of Pex1/Pex6 from Saccharomyces cerevisiae, with an endogenous protein substrate trapped in the central pore of the catalytically active second ring (D2). Pairs of Pex1/Pex6(D2) subdomains engage the substrate via a staircase of pore-1 loops with distinct properties. The first ring (D1) is catalytically inactive but undergoes significant conformational changes resulting in alternate widening and narrowing of its pore. These events are fueled by ATP hydrolysis in the D2 ring and disengagement of a "twin-seam" Pex1/Pex6(D2) heterodimer from the staircase. Mechanical forces are propagated in a unique manner along Pex1/Pex6 interfaces that are not available in homo-oligomeric AAA-ATPases. Our structural analysis reveals the mechanisms of how Pex1 and Pex6 coordinate to achieve substrate translocation.
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Affiliation(s)
- Maximilian Rüttermann
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Michelle Koci
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Pascal Lill
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | - Ermis Dionysios Geladas
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Farnusch Kaschani
- Analytics Core Facility Essen, Center of Medical Biotechnology (ZMB), Faculty of Biology, University of Duisburg-Essen, Essen, Germany
| | - Björn Udo Klink
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany
| | - Ralf Erdmann
- Institute for Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Ruhr-University Bochum, Bochum, Germany
| | - Christos Gatsogiannis
- Institute for Medical Physics and Biophysics, University Münster, Münster, Germany.
- Center for Soft Nanoscience (SoN), University Münster, Münster, Germany.
- Department of Structural Biochemistry, Max Planck Institute of Molecular Physiology, Dortmund, Germany.
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6
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Fresenius HL, Gaur D, Wohlever ML. The AAA+ protein Msp1 selects substrates by recognizing a hydrophobic mismatch between the substrate transmembrane domain and the lipid bilayer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.11.548587. [PMID: 37502992 PMCID: PMC10369969 DOI: 10.1101/2023.07.11.548587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
An essential aspect of protein quality control is enzymatic removal of membrane proteins from the lipid bilayer. Failures in this essential cellular process are associated with neurodegenerative diseases and cancer. Msp1 is a AAA+ ( A TPases A ssociated with diverse cellular A ctivities) protein that removes mistargeted proteins from the outer mitochondrial membrane (OMM). How Msp1 selectively recognizes and extracts substrates within the complex OMM ecosystem, and the role of the lipid bilayer on these processes is unknown. Here, we describe the development of fully defined, rapid, and quantitative extraction assay that retains physiological substrate selectivity. Using this new assay, we systematically modified both substrates and the lipid environment to demonstrate that Msp1 recognizes substrates by a hydrophobic mismatch between the substrate TMD and the lipid bilayer. We further demonstrate that the rate limiting step in Msp1 activity is extraction of the TMD from the lipid bilayer. Together, these results provide foundational insights into how the lipid bilayer influences AAA+ mediated membrane protein extraction.
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7
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Cooney I, Schubert HL, Cedeno K, Lin HJL, Price JC, Hill CP, Shen PS. Visualization of the Cdc48 AAA+ ATPase protein unfolding pathway. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.13.540638. [PMID: 38654823 PMCID: PMC11037871 DOI: 10.1101/2023.05.13.540638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
The Cdc48 AAA+ ATPase is an abundant and essential enzyme that unfolds substrates in multiple protein quality control pathways. The enzyme includes two conserved AAA+ ATPase cassettes, D1 and D2, that assemble as hexameric rings with D1 stacked above D2. Here, we report an ensemble of structures of Cdc48 affinity purified from lysate in complex with the adaptor Shp1 in the act of unfolding substrate. Our analysis reveals a continuum of structural snapshots that spans the entire translocation cycle. These data reveal new elements of Shp1-Cdc48 binding and support a "hand-over-hand" mechanism in which the sequential movement of individual subunits is closely coordinated. D1 hydrolyzes ATP and disengages from substrate prior to D2, while D2 rebinds ATP and re-engages with substrate prior to D1, thereby explaining the dominant role played by D2 in substrate translocation/unfolding.
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Affiliation(s)
- Ian Cooney
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Heidi L. Schubert
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Karina Cedeno
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Hsien-Jung L. Lin
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - John C Price
- Department of Chemistry and Biochemistry, C100 BNSN, Brigham Young University, Provo, UT, 84602, USA
| | - Christopher P Hill
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
| | - Peter S Shen
- Department of Biochemistry, 15 N. Medical Drive East, University of Utah, Salt Lake City, UT, 84112, USA
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8
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Onishi M, Kubota M, Duan L, Tian Y, Okamoto K. The GET pathway serves to activate Atg32-mediated mitophagy by ER targeting of the Ppg1-Far complex. Life Sci Alliance 2023; 6:e202201640. [PMID: 36697253 PMCID: PMC9880027 DOI: 10.26508/lsa.202201640] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/27/2023] Open
Abstract
Mitophagy removes defective or superfluous mitochondria via selective autophagy. In yeast, the pro-mitophagic protein Atg32 localizes to the mitochondrial surface and interacts with the scaffold protein Atg11 to promote degradation of mitochondria. Although Atg32-Atg11 interactions are thought to be stabilized by Atg32 phosphorylation, how this posttranslational modification is regulated remains obscure. Here, we show that cells lacking the guided entry of the tail-anchored protein (GET) pathway exhibit reduced Atg32 phosphorylation and Atg32-Atg11 interactions, which can be rescued by additional loss of the ER-resident Ppg1-Far complex, a multi-subunit phosphatase negatively acting in mitophagy. In GET-deficient cells, Ppg1-Far is predominantly localized to mitochondria. An artificial ER anchoring of Ppg1-Far in GET-deficient cells significantly ameliorates defects in Atg32-Atg11 interactions and mitophagy. Moreover, disruption of GET and Msp1, an AAA-ATPase that extracts non-mitochondrial proteins localized to the mitochondrial surface, elicits synthetic defects in mitophagy. Collectively, we propose that the GET pathway mediates ER targeting of Ppg1-Far, thereby preventing dysregulated suppression of mitophagy activation.
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Affiliation(s)
- Mashun Onishi
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Mitsutaka Kubota
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Lan Duan
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yuan Tian
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Koji Okamoto
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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9
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McKenna MJ, Shao S. The Endoplasmic Reticulum and the Fidelity of Nascent Protein Localization. Cold Spring Harb Perspect Biol 2023; 15:a041249. [PMID: 36041782 PMCID: PMC9979852 DOI: 10.1101/cshperspect.a041249] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
High-fidelity protein localization is essential to define the identities and functions of different organelles and to maintain cellular homeostasis. Accurate localization of nascent proteins requires specific protein targeting pathways as well as quality control (QC) mechanisms to remove mislocalized proteins. The endoplasmic reticulum (ER) is the first destination for approximately one-third of the eukaryotic proteome and a major site of protein biosynthesis and QC. In mammalian cells, trafficking from the ER provides nascent proteins access to the extracellular space and essentially every cellular membrane and organelle except for mitochondria and possibly peroxisomes. Here, we discuss the biosynthetic mechanisms that deliver nascent proteins to the ER and the QC mechanisms that interface with the ER to correct or degrade mislocalized proteins.
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Affiliation(s)
- Michael J McKenna
- Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts 02115, USA
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, Blavatnik Institute, Boston, Massachusetts 02115, USA
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10
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Kocaman S, Lo YH, Krahn JM, Sobhany M, Dandey VP, Petrovich ML, Etigunta SK, Williams JG, Deterding LJ, Borgnia MJ, Stanley RE. Communication network within the essential AAA-ATPase Rix7 drives ribosome assembly. PNAS NEXUS 2022; 1:pgac118. [PMID: 36090660 PMCID: PMC9437592 DOI: 10.1093/pnasnexus/pgac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/08/2022] [Indexed: 02/06/2023]
Abstract
Rix7 is an essential AAA+ ATPase that functions during the early stages of ribosome biogenesis. Rix7 is composed of three domains including an N-terminal domain (NTD) and two AAA+ domains (D1 and D2) that assemble into an asymmetric stacked hexamer. It was recently established that Rix7 is a presumed protein translocase that removes substrates from preribosomes by translocating them through its central pore. However, how the different domains of Rix7 coordinate their activities within the overall hexameric structure was unknown. We captured cryo-electron microscopy (EM) structures of single and double Walker B variants of full length Rix7. The disordered NTD was not visible in the cryo-EM reconstructions, but cross-linking mass spectrometry revealed that the NTD can associate with the central channel in vitro. Deletion of the disordered NTD enabled us to obtain a structure of the Rix7 hexamer to 2.9 Å resolution, providing high resolution details of critical motifs involved in substrate translocation and interdomain communication. This structure coupled with cell-based assays established that the linker connecting the D1 and D2 domains as well as the pore loops lining the central channel are essential for formation of the large ribosomal subunit. Together, our work shows that Rix7 utilizes a complex communication network to drive ribosome biogenesis.
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Affiliation(s)
- Seda Kocaman
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Yu-Hua Lo
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Juno M Krahn
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mack Sobhany
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Venkata P Dandey
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Matthew L Petrovich
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Suhas K Etigunta
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Jason G Williams
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Leesa J Deterding
- Department of Health and Human Services, Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Mario J Borgnia
- Department of Health and Human Services, Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Robin E Stanley
- Department of Health and Human Services, Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, 111 T. W. Alexander Drive, Research Triangle Park, NC 27709, USA
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11
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Matsumoto S, Ono S, Shinoda S, Kakuta C, Okada S, Ito T, Numata T, Endo T. GET pathway mediates transfer of mislocalized tail-anchored proteins from mitochondria to the ER. J Cell Biol 2022; 221:213171. [PMID: 35442388 DOI: 10.1083/jcb.202104076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 01/18/2022] [Accepted: 03/14/2022] [Indexed: 11/22/2022] Open
Abstract
Tail-anchored (TA) membrane proteins have a potential risk to be mistargeted to the mitochondrial outer membrane (OM). Such mislocalized TA proteins can be extracted by the mitochondrial AAA-ATPase Msp1 from the OM and transferred to the ER for ER protein quality control involving ubiquitination by the ER-resident Doa10 complex. Yet it remains unclear how the extracted TA proteins can move to the ER crossing the aqueous cytosol and whether this transfer to the ER is essential for the clearance of mislocalized TA proteins. Here we show by time-lapse microscopy that mislocalized TA proteins, including an authentic ER-TA protein, indeed move from mitochondria to the ER in a manner strictly dependent on Msp1 expression. The Msp1-dependent mitochondria-to-ER transfer of TA proteins is blocked by defects in the GET system, and this block is not due to impaired Doa10 functions. Thus, the GET pathway facilitates the transfer of mislocalized TA proteins from mitochondria to the ER.
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Affiliation(s)
- Shunsuke Matsumoto
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan.,Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Suzuka Ono
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
| | - Saori Shinoda
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Chika Kakuta
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Satoshi Okada
- Department of Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takashi Ito
- Department of Biochemistry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomoyuki Numata
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
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12
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Abstract
The p97 AAA+ATPase is an essential and abundant regulator of protein homeostasis that plays a central role in unfolding ubiquitylated substrates. Here we report two cryo-EM structures of human p97 in complex with its p47 adaptor. One of the conformations is six-fold symmetric, corresponds to previously reported structures of p97, and lacks bound substrate. The other structure adopts a helical conformation, displays substrate running in an extended conformation through the pore of the p97 hexamer, and resembles structures reported for other AAA unfoldases. These findings support the model that p97 utilizes a "hand-over-hand" mechanism in which two residues of the substrate are translocated for hydrolysis of two ATPs, one in each of the two p97 AAA ATPase rings. Proteomics analysis supports the model that one p97 complex can bind multiple substrate adaptors or binding partners, and can process substrates with multiple types of ubiquitin modification.
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13
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Wang L, Toutkoushian H, Belyy V, Kokontis CY, Walter P. Conserved structural elements specialize ATAD1 as a membrane protein extraction machine. eLife 2022; 11:e73941. [PMID: 35550246 PMCID: PMC9273213 DOI: 10.7554/elife.73941] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 05/12/2022] [Indexed: 11/13/2022] Open
Abstract
The mitochondrial AAA (ATPase Associated with diverse cellular Activities) protein ATAD1 (in humans; Msp1 in yeast) removes mislocalized membrane proteins, as well as stuck import substrates from the mitochondrial outer membrane, facilitating their re-insertion into their cognate organelles and maintaining mitochondria's protein import capacity. In doing so, it helps to maintain proteostasis in mitochondria. How ATAD1 tackles the energetic challenge to extract hydrophobic membrane proteins from the lipid bilayer and what structural features adapt ATAD1 for its particular function has remained a mystery. Previously, we determined the structure of Msp1 in complex with a peptide substrate (Wang et al., 2020). The structure showed that Msp1's mechanism follows the general principle established for AAA proteins while adopting several structural features that specialize it for its function. Among these features in Msp1 was the utilization of multiple aromatic amino acids to firmly grip the substrate in the central pore. However, it was not clear whether the aromatic nature of these amino acids were required, or if they could be functionally replaced by aliphatic amino acids. In this work, we determined the cryo-EM structures of the human ATAD1 in complex with a peptide substrate at near atomic resolution. The structures show that phylogenetically conserved structural elements adapt ATAD1 for its function while generally adopting a conserved mechanism shared by many AAA proteins. We developed a microscopy-based assay reporting on protein mislocalization, with which we directly assessed ATAD1's activity in live cells and showed that both aromatic amino acids in pore-loop 1 are required for ATAD1's function and cannot be substituted by aliphatic amino acids. A short α-helix at the C-terminus strongly facilitates ATAD1's oligomerization, a structural feature that distinguishes ATAD1 from its closely related proteins.
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Affiliation(s)
- Lan Wang
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
- Howard Hughes Medical Institute, University of California at San FranciscoSan FranciscoUnited States
| | - Hannah Toutkoushian
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
- Howard Hughes Medical Institute, University of California at San FranciscoSan FranciscoUnited States
| | - Vladislav Belyy
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
- Howard Hughes Medical Institute, University of California at San FranciscoSan FranciscoUnited States
| | - Claire Y Kokontis
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California at San FranciscoSan FranciscoUnited States
- Howard Hughes Medical Institute, University of California at San FranciscoSan FranciscoUnited States
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14
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Eldeeb MA, Thomas RA, Ragheb MA, Fallahi A, Fon EA. Mitochondrial quality control in health and in Parkinson's disease. Physiol Rev 2022; 102:1721-1755. [PMID: 35466694 DOI: 10.1152/physrev.00041.2021] [Citation(s) in RCA: 74] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
As a central hub for cellular metabolism and intracellular signalling, the mitochondrion is a pivotal organelle, dysfunction of which has been linked to several human diseases including neurodegenerative disorders, and in particular Parkinson's disease. An inherent challenge that mitochondria face is the continuous exposure to diverse stresses which increase their likelihood of dysregulation. In response, eukaryotic cells have evolved sophisticated quality control mechanisms to monitor, identify, repair and/or eliminate abnormal or misfolded proteins within the mitochondrion and/or the dysfunctional mitochondrion itself. Chaperones identify unstable or otherwise abnormal conformations in mitochondrial proteins and can promote their refolding to recover their correct conformation and stability. However, if repair is not possible, the abnormal protein is selectively degraded to prevent potentially damaging interactions with other proteins or its oligomerization into toxic multimeric complexes. The autophagic-lysosomal system and the ubiquitin-proteasome system mediate the selective and targeted degradation of such abnormal or misfolded protein species. Mitophagy (a specific kind of autophagy) mediates the selective elimination of dysfunctional mitochondria, in order to prevent the deleterious effects the dysfunctional organelles within the cell. Despite our increasing understanding of the molecular responses toward dysfunctional mitochondria, many key aspects remain relatively poorly understood. Herein, we review the emerging mechanisms of mitochondrial quality control including quality control strategies coupled to mitochondrial import mechanisms. In addition, we review the molecular mechanisms regulating mitophagy with an emphasis on the regulation of PINK1/PARKIN-mediated mitophagy in cellular physiology and in the context of Parkinson's disease cell biology.
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Affiliation(s)
- Mohamed A Eldeeb
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Rhalena A Thomas
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Mohamed A Ragheb
- Chemistry Department (Biochemistry Division), Faculty of Science, Cairo University, Giza, Egypt
| | - Armaan Fallahi
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Edward A Fon
- McGill Parkinson Program, Neurodegenerative Diseases Group, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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15
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Hsieh HH, Shan SO. Fidelity of Cotranslational Protein Targeting to the Endoplasmic Reticulum. Int J Mol Sci 2021; 23:ijms23010281. [PMID: 35008707 PMCID: PMC8745203 DOI: 10.3390/ijms23010281] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 12/17/2021] [Accepted: 12/18/2021] [Indexed: 02/04/2023] Open
Abstract
Fidelity of protein targeting is essential for the proper biogenesis and functioning of organelles. Unlike replication, transcription and translation processes, in which multiple mechanisms to recognize and reject noncognate substrates are established in energetic and molecular detail, the mechanisms by which cells achieve a high fidelity in protein localization remain incompletely understood. Signal recognition particle (SRP), a conserved pathway to mediate the localization of membrane and secretory proteins to the appropriate cellular membrane, provides a paradigm to understand the molecular basis of protein localization in the cell. In this chapter, we review recent progress in deciphering the molecular mechanisms and substrate selection of the mammalian SRP pathway, with an emphasis on the key role of the cotranslational chaperone NAC in preventing protein mistargeting to the ER and in ensuring the organelle specificity of protein localization.
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16
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den Brave F, Gupta A, Becker T. Protein Quality Control at the Mitochondrial Surface. Front Cell Dev Biol 2021; 9:795685. [PMID: 34926473 PMCID: PMC8678412 DOI: 10.3389/fcell.2021.795685] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/05/2021] [Indexed: 12/14/2022] Open
Abstract
Mitochondria contain two membranes, the outer and inner membrane. The outer membrane fulfills crucial functions for the communication of mitochondria with the cellular environment like exchange of lipids via organelle contact sites, the transport of metabolites and the formation of a signaling platform in apoptosis and innate immunity. The translocase of the outer membrane (TOM complex) forms the entry gate for the vast majority of precursor proteins that are produced on cytosolic ribosomes. Surveillance of the functionality of outer membrane proteins is critical for mitochondrial functions and biogenesis. Quality control mechanisms remove defective and mistargeted proteins from the outer membrane as well as precursor proteins that clog the TOM complex. Selective degradation of single proteins is also an important mode to regulate mitochondrial dynamics and initiation of mitophagy pathways. Whereas inner mitochondrial compartments are equipped with specific proteases, the ubiquitin-proteasome system is a central player in protein surveillance on the mitochondrial surface. In this review, we summarize our current knowledge about the molecular mechanisms that govern quality control of proteins at the outer mitochondrial membrane.
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Affiliation(s)
- Fabian den Brave
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Arushi Gupta
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, University of Bonn, Bonn, Germany
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17
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Mehlhorn DG, Asseck LY, Grefen C. Looking for a safe haven: tail-anchored proteins and their membrane insertion pathways. PLANT PHYSIOLOGY 2021; 187:1916-1928. [PMID: 35235667 PMCID: PMC8644595 DOI: 10.1093/plphys/kiab298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 06/05/2021] [Indexed: 06/14/2023]
Abstract
Insertion of membrane proteins into the lipid bilayer is a crucial step during their biosynthesis. Eukaryotic cells face many challenges in directing these proteins to their predestined target membrane. The hydrophobic signal peptide or transmembrane domain (TMD) of the nascent protein must be shielded from the aqueous cytosol and its target membrane identified followed by transport and insertion. Components that evolved to deal with each of these challenging steps range from chaperones to receptors, insertases, and sophisticated translocation complexes. One prominent translocation pathway for most proteins is the signal recognition particle (SRP)-dependent pathway which mediates co-translational translocation of proteins across or into the endoplasmic reticulum (ER) membrane. This textbook example of protein insertion is stretched to its limits when faced with secretory or membrane proteins that lack an amino-terminal signal sequence or TMD. Particularly, a large group of so-called tail-anchored (TA) proteins that harbor a single carboxy-terminal TMD require an alternative, post-translational insertion route into the ER membrane. In this review, we summarize the current research in TA protein insertion with a special focus on plants, address challenges, and highlight future research avenues.
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Affiliation(s)
- Dietmar G Mehlhorn
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Lisa Y Asseck
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Christopher Grefen
- Faculty of Biology and Biotechnology, Molecular and Cellular Botany, University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
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18
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Antico O, Ordureau A, Stevens M, Singh F, Nirujogi RS, Gierlinski M, Barini E, Rickwood ML, Prescott A, Toth R, Ganley IG, Harper JW, Muqit MMK. Global ubiquitylation analysis of mitochondria in primary neurons identifies endogenous Parkin targets following activation of PINK1. SCIENCE ADVANCES 2021; 7:eabj0722. [PMID: 34767452 PMCID: PMC8589319 DOI: 10.1126/sciadv.abj0722] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 09/21/2021] [Indexed: 05/16/2023]
Abstract
How activation of PINK1 and Parkin leads to elimination of damaged mitochondria by mitophagy is largely based on cell lines with few studies in neurons. Here, we have undertaken proteomic analysis of mitochondria from mouse neurons to identify ubiquitylated substrates of endogenous Parkin. Comparative analysis with human iNeuron datasets revealed a subset of 49 PINK1 activation–dependent diGLY sites in 22 proteins conserved across mouse and human systems. We use reconstitution assays to demonstrate direct ubiquitylation by Parkin in vitro. We also identified a subset of cytoplasmic proteins recruited to mitochondria that undergo PINK1 and Parkin independent ubiquitylation, indicating the presence of alternate ubiquitin E3 ligase pathways that are activated by mitochondrial depolarization in neurons. Last, we have developed an online resource to search for ubiquitin sites and enzymes in mitochondria of neurons, MitoNUb. These findings will aid future studies to understand Parkin activation in neuronal subtypes.
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Affiliation(s)
- Odetta Antico
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Alban Ordureau
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael Stevens
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Francois Singh
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Raja S. Nirujogi
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Marek Gierlinski
- Data Analysis Group, Division of Computational Biology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Erica Barini
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Mollie L. Rickwood
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Alan Prescott
- Dundee Imaging Facility, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Rachel Toth
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Ian G. Ganley
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - J. Wade Harper
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Miratul M. K. Muqit
- MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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19
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Quality control of protein import into mitochondria. Biochem J 2021; 478:3125-3143. [PMID: 34436539 DOI: 10.1042/bcj20190584] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022]
Abstract
Mitochondria import about 1000 proteins that are produced as precursors on cytosolic ribosomes. Defects in mitochondrial protein import result in the accumulation of non-imported precursor proteins and proteotoxic stress. The cell is equipped with different quality control mechanisms to monitor protein transport into mitochondria. First, molecular chaperones guide unfolded proteins to mitochondria and deliver non-imported proteins to proteasomal degradation. Second, quality control factors remove translocation stalled precursor proteins from protein translocases. Third, protein translocases monitor protein sorting to mitochondrial subcompartments. Fourth, AAA proteases of the mitochondrial subcompartments remove mislocalized or unassembled proteins. Finally, impaired efficiency of protein transport is an important sensor for mitochondrial dysfunction and causes the induction of cellular stress responses, which could eventually result in the removal of the defective mitochondria by mitophagy. In this review, we summarize our current understanding of quality control mechanisms that govern mitochondrial protein transport.
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20
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Nuebel E, Morgan JT, Fogarty S, Winter JM, Lettlova S, Berg JA, Chen YC, Kidwell CU, Maschek JA, Clowers KJ, Argyriou C, Chen L, Wittig I, Cox JE, Roh-Johnson M, Braverman N, Bonkowsky J, Gygi SP, Rutter J. The biochemical basis of mitochondrial dysfunction in Zellweger Spectrum Disorder. EMBO Rep 2021; 22:e51991. [PMID: 34351705 DOI: 10.15252/embr.202051991] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 06/21/2021] [Accepted: 07/12/2021] [Indexed: 01/09/2023] Open
Abstract
Peroxisomal biogenesis disorders (PBDs) are genetic disorders of peroxisome biogenesis and metabolism that are characterized by profound developmental and neurological phenotypes. The most severe class of PBDs-Zellweger spectrum disorder (ZSD)-is caused by mutations in peroxin genes that result in both non-functional peroxisomes and mitochondrial dysfunction. It is unclear, however, how defective peroxisomes contribute to mitochondrial impairment. In order to understand the molecular basis of this inter-organellar relationship, we investigated the fate of peroxisomal mRNAs and proteins in ZSD model systems. We found that peroxins were still expressed and a subset of them accumulated on the mitochondrial membrane, which resulted in gross mitochondrial abnormalities and impaired mitochondrial metabolic function. We showed that overexpression of ATAD1, a mitochondrial quality control factor, was sufficient to rescue several aspects of mitochondrial function in human ZSD fibroblasts. Together, these data suggest that aberrant peroxisomal protein localization is necessary and sufficient for the devastating mitochondrial morphological and metabolic phenotypes in ZSDs.
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Affiliation(s)
- Esther Nuebel
- Howard Hughes Medical Institute, Salt Lake City, UT, USA.,Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.,Department of Biomedical Sciences, Noorda College of Osteopathic Medicine, Provo, USA
| | - Jeffrey T Morgan
- Howard Hughes Medical Institute, Salt Lake City, UT, USA.,Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Sarah Fogarty
- Howard Hughes Medical Institute, Salt Lake City, UT, USA.,Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Jacob M Winter
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Sandra Lettlova
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Jordan A Berg
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Yu-Chan Chen
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Chelsea U Kidwell
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - J Alan Maschek
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.,Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA.,Metabolomics, Proteomics and Mass Spectrometry Core Research Facilities, University of Utah, Salt Lake City, UT, USA
| | - Katie J Clowers
- Department of Cell Biology, Harvard University School of Medicine, Boston, MA, USA
| | | | - Lingxiao Chen
- Department of Pathology, McGill University, Montreal, ON, Canada
| | - Ilka Wittig
- Functional Proteomics, Faculty of Medicine, Goethe University, Frankfurt am Main, Germany
| | - James E Cox
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.,Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA.,Metabolomics, Proteomics and Mass Spectrometry Core Research Facilities, University of Utah, Salt Lake City, UT, USA
| | - Minna Roh-Johnson
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Nancy Braverman
- Department of Human Genetics, McGill University, Montreal, ON, Canada.,Department of Pediatrics, Research Institute of the McGill University Health Centre, Montreal, ON, Canada
| | - Joshua Bonkowsky
- Primary Children's Hospital, University of Utah, Salt Lake City, UT, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard University School of Medicine, Boston, MA, USA
| | - Jared Rutter
- Howard Hughes Medical Institute, Salt Lake City, UT, USA.,Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.,Diabetes & Metabolism Research Center, University of Utah, Salt Lake City, UT, USA
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21
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Xavierselvan M, Divecha HR, Hajra M, Silwal S, Macwan I. Towards Tumor Targeting via Invasive Assay Using Magnetospirillum magneticum. Front Microbiol 2021; 12:697132. [PMID: 34367097 PMCID: PMC8341810 DOI: 10.3389/fmicb.2021.697132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 06/21/2021] [Indexed: 12/12/2022] Open
Abstract
Magnetospirillum magneticum (AMB-1) are a species of magnetotactic bacteria (MTB) that are capable of orienting along the earth's magnetic field lines through their organelles called magnetosomes. Many studies have shown that certain engineered bacteria can infect the tumor cells, resulting in a controlled death of a tumor. This work deals with a technique utilizing AMB-1 along a predefined path through magnetotaxis, which can pave a way for selective doping as well as isolation of the tumor cells from a group of healthy cells through a magnetic invasive assay. For such a control, a tiny mesh of vertical electrical coils each having a diameter of ∼3 mm is fabricated, which establishes the path for the bacteria to move along the magnetic field lines. The molecular dynamics (MD) simulations at the interface of the bacterial cell surface proteins (MSP-1 and flagellin) and Chinese hamster ovary (CHO) cell surface containing cytoplasmic and extracellular proteins (BSG, B2M, SDC1, AIMP1, and FOS) are shown to establish an association between the AMB-1 and the host CHO cells. It is found that the CHO protein structure is compromised, which disables the activation of its defense function, allowing the bacteria to interact and survive. The experimental demonstration involves the CHO cells' interaction with the AMB-1 and isolation of selected CHO cells. It is found that AMB-1-integrated CHO cells successfully moved along the magnetic field lines generated by the coils. Statistical analysis performed for the assay showed that AMB-1 cells were found to be viable after co-incubating with CHO cells, and the number of viable cells post co-incubation over a period of 24 h showed a slight decrease in both cell population. Overall, 51% of AMB-1 cells and 67% of CHO cells were found viable 24 h post co-incubation. Scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDAX) analysis revealed AMB-1/CHO cell morphology, the potential interaction between them, and the presence of magnetosomes with trace amounts of iron in the AMB-1-interacted CHO cells, confirming the successful AMB-1 integration.
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Affiliation(s)
- Marvin Xavierselvan
- Department of Biomedical Engineering, Tufts University, Medford, MA, United States
| | - Heena R. Divecha
- Department of Biomedical Engineering, University of Bridgeport, Bridgeport, CT, United States
| | - Mamta Hajra
- Department of Biomedical Engineering, University of Bridgeport, Bridgeport, CT, United States
| | - Sushila Silwal
- Department of Biomedical Engineering, University of Bridgeport, Bridgeport, CT, United States
| | - Isaac Macwan
- Department of Electrical and Biomedical Engineering, Fairfield University, Fairfield, CT, United States
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22
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Farkas Á, Bohnsack KE. Capture and delivery of tail-anchored proteins to the endoplasmic reticulum. J Cell Biol 2021; 220:212470. [PMID: 34264263 PMCID: PMC8287540 DOI: 10.1083/jcb.202105004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 11/22/2022] Open
Abstract
Tail-anchored (TA) proteins fulfill diverse cellular functions within different organellar membranes. Their characteristic C-terminal transmembrane segment renders TA proteins inherently prone to aggregation and necessitates their posttranslational targeting. The guided entry of TA proteins (GET in yeast)/transmembrane recognition complex (TRC in humans) pathway represents a major route for TA proteins to the endoplasmic reticulum (ER). Here, we review important new insights into the capture of nascent TA proteins at the ribosome by the GET pathway pretargeting complex and the mechanism of their delivery into the ER membrane by the GET receptor insertase. Interestingly, several alternative routes by which TA proteins can be targeted to the ER have emerged, raising intriguing questions about how selectivity is achieved during TA protein capture. Furthermore, mistargeting of TA proteins is a fundamental cellular problem, and we discuss the recently discovered quality control machineries in the ER and outer mitochondrial membrane for displacing mislocalized TA proteins.
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Affiliation(s)
- Ákos Farkas
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
| | - Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany
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23
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Sensing, signaling and surviving mitochondrial stress. Cell Mol Life Sci 2021; 78:5925-5951. [PMID: 34228161 PMCID: PMC8316193 DOI: 10.1007/s00018-021-03887-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 06/15/2021] [Accepted: 06/22/2021] [Indexed: 12/11/2022]
Abstract
Mitochondrial fidelity is a key determinant of longevity and was found to be perturbed in a multitude of disease contexts ranging from neurodegeneration to heart failure. Tight homeostatic control of the mitochondrial proteome is a crucial aspect of mitochondrial function, which is severely complicated by the evolutionary origin and resulting peculiarities of the organelle. This is, on one hand, reflected by a range of basal quality control factors such as mitochondria-resident chaperones and proteases, that assist in import and folding of precursors as well as removal of aggregated proteins. On the other hand, stress causes the activation of several additional mechanisms that counteract any damage that may threaten mitochondrial function. Countermeasures depend on the location and intensity of the stress and on a range of factors that are equipped to sense and signal the nature of the encountered perturbation. Defective mitochondrial import activates mechanisms that combat the accumulation of precursors in the cytosol and the import pore. To resolve proteotoxic stress in the organelle interior, mitochondria depend on nuclear transcriptional programs, such as the mitochondrial unfolded protein response and the integrated stress response. If organelle damage is too severe, mitochondria signal for their own destruction in a process termed mitophagy, thereby preventing further harm to the mitochondrial network and allowing the cell to salvage their biological building blocks. Here, we provide an overview of how different types and intensities of stress activate distinct pathways aimed at preserving mitochondrial fidelity.
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Ng MYW, Wai T, Simonsen A. Quality control of the mitochondrion. Dev Cell 2021; 56:881-905. [PMID: 33662258 DOI: 10.1016/j.devcel.2021.02.009] [Citation(s) in RCA: 130] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/06/2021] [Accepted: 02/08/2021] [Indexed: 12/22/2022]
Abstract
Mitochondria are essential organelles that execute and coordinate various metabolic processes in the cell. Mitochondrial dysfunction severely affects cell fitness and contributes to disease. Proper organellar function depends on the biogenesis and maintenance of mitochondria and its >1,000 proteins. As a result, the cell has evolved mechanisms to coordinate protein and organellar quality control, such as the turnover of proteins via mitochondria-associated degradation, the ubiquitin-proteasome system, and mitoproteases, as well as the elimination of mitochondria through mitophagy. Specific quality control mechanisms are engaged depending upon the nature and severity of mitochondrial dysfunction, which can also feed back to elicit transcriptional or proteomic remodeling by the cell. Here, we will discuss the current understanding of how these different quality control mechanisms are integrated and overlap to maintain protein and organellar quality and how they may be relevant for cellular and organismal health.
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Affiliation(s)
- Matthew Yoke Wui Ng
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway
| | - Timothy Wai
- Institut Pasteur CNRS UMR 3691, 25-28 Rue du Docteur Roux, Paris, France.
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway.
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Abstract
Mitochondria contain about 1,000-1,500 proteins that fulfil multiple functions. Mitochondrial proteins originate from two genomes: mitochondrial and nuclear. Hence, proper mitochondrial function requires synchronization of gene expression in the nucleus and in mitochondria and necessitates efficient import of mitochondrial proteins into the organelle from the cytosol. Furthermore, the mitochondrial proteome displays high plasticity to allow the adaptation of mitochondrial function to cellular requirements. Maintenance of this complex and adaptable mitochondrial proteome is challenging, but is of crucial importance to cell function. Defects in mitochondrial proteostasis lead to proteotoxic insults and eventually cell death. Different quality control systems monitor the mitochondrial proteome. The cytosolic ubiquitin-proteasome system controls protein transport across the mitochondrial outer membrane and removes damaged or mislocalized proteins. Concomitantly, a number of mitochondrial chaperones and proteases govern protein folding and degrade damaged proteins inside mitochondria. The quality control factors also regulate processing and turnover of native proteins to control protein import, mitochondrial metabolism, signalling cascades, mitochondrial dynamics and lipid biogenesis, further ensuring proper function of mitochondria. Thus, mitochondrial protein quality control mechanisms are of pivotal importance to integrate mitochondria into the cellular environment.
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Wang L, Walter P. Msp1/ATAD1 in Protein Quality Control and Regulation of Synaptic Activities. Annu Rev Cell Dev Biol 2020; 36:141-164. [DOI: 10.1146/annurev-cellbio-031220-015840] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondrial function depends on the efficient import of proteins synthesized in the cytosol. When cells experience stress, the efficiency and faithfulness of the mitochondrial protein import machinery are compromised, leading to homeostatic imbalances and damage to the organelle. Yeast Msp1 (mitochondrial sorting of proteins 1) and mammalian ATAD1 (ATPase family AAA domain–containing 1) are orthologous AAA proteins that, fueled by ATP hydrolysis, recognize and extract mislocalized membrane proteins from the outer mitochondrial membrane. Msp1 also extracts proteins that have become stuck in the import channel. The extracted proteins are targeted for proteasome-dependent degradation or, in the case of mistargeted tail-anchored proteins, are given another chance to be routed correctly. In addition, ATAD1 is implicated in the regulation of synaptic plasticity, mediating the release of neurotransmitter receptors from postsynaptic scaffolds to allow their trafficking. Here we discuss how structural and functional specialization imparts the unique properties that allow Msp1/ATAD1 ATPases to fulfill these diverse functions and also highlight outstanding questions in the field.
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Affiliation(s)
- Lan Wang
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA;,
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94143, USA;,
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94122, USA
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Flecken M, Wang H, Popilka L, Hartl FU, Bracher A, Hayer-Hartl M. Dual Functions of a Rubisco Activase in Metabolic Repair and Recruitment to Carboxysomes. Cell 2020; 183:457-473.e20. [PMID: 32979320 DOI: 10.1016/j.cell.2020.09.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/13/2020] [Accepted: 09/01/2020] [Indexed: 01/19/2023]
Abstract
Rubisco, the key enzyme of CO2 fixation in photosynthesis, is prone to inactivation by inhibitory sugar phosphates. Inhibited Rubisco undergoes conformational repair by the hexameric AAA+ chaperone Rubisco activase (Rca) in a process that is not well understood. Here, we performed a structural and mechanistic analysis of cyanobacterial Rca, a close homolog of plant Rca. In the Rca:Rubisco complex, Rca is positioned over the Rubisco catalytic site under repair and pulls the N-terminal tail of the large Rubisco subunit (RbcL) into the hexamer pore. Simultaneous displacement of the C terminus of the adjacent RbcL opens the catalytic site for inhibitor release. An alternative interaction of Rca with Rubisco is mediated by C-terminal domains that resemble the small Rubisco subunit. These domains, together with the N-terminal AAA+ hexamer, ensure that Rca is packaged with Rubisco into carboxysomes. The cyanobacterial Rca is a dual-purpose protein with functions in Rubisco repair and carboxysome organization.
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Affiliation(s)
- Mirkko Flecken
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Huping Wang
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Leonhard Popilka
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - F Ulrich Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Andreas Bracher
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Manajit Hayer-Hartl
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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