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Ku D, Yang Y, Park Y, Jang D, Lee N, Lee YK, Lee K, Lee J, Han YB, Jang S, Choi SR, Ha YJ, Choi YS, Jeong WJ, Lee YJ, Lee KJ, Cha S, Kim Y. SLIRP promotes autoimmune diseases by amplifying antiviral signaling via positive feedback regulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.28.587146. [PMID: 38915695 PMCID: PMC11195051 DOI: 10.1101/2024.03.28.587146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
The abnormal innate immune response is a prominent feature underlying autoimmune diseases. One emerging factor that can trigger dysregulated immune activation is cytosolic mitochondrial double-stranded RNAs (mt-dsRNAs). However, the mechanism by which mt-dsRNAs stimulate immune responses remains poorly understood. Here, we discover SRA stem-loop interacting RNA binding protein (SLIRP) as a key amplifier of mt-dsRNA-triggered antiviral signals. In autoimmune diseases, SLIRP is commonly upregulated, and targeted knockdown of SLIRP dampens the interferon response. We find that the activation of melanoma differentiation-associated gene 5 (MDA5) by exogenous dsRNAs upregulates SLIRP, which then stabilizes mt-dsRNAs and promotes their cytosolic release to activate MDA5 further, augmenting the interferon response. Furthermore, the downregulation of SLIRP partially rescues the abnormal interferon-stimulated gene expression in autoimmune patients' primary cells and makes cells vulnerable to certain viral infections. Our study unveils SLIRP as a pivotal mediator of interferon response through positive feedback amplification of antiviral signaling.
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Affiliation(s)
- Doyeong Ku
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yewon Yang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Youngran Park
- Center for RNA Research, Institute of Basic Science, Seoul, 08826, Republic of Korea
- School of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Daesong Jang
- Department of Oral and Maxillofacial Diagnostic Science, Center for Orphaned Autoimmune Disorders, University of Florida College of Dentistry, Gainesville, Florida, 32610, United States of America
| | - Namseok Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Yong-ki Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Keonyong Lee
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
| | - Jaeseon Lee
- R&D Institute, ORGANOIDSCIENCES Ltd., Seongnam, 13488, Republic of Korea
| | - Yeon Bi Han
- Department of Pathology and Translational Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
| | - Soojin Jang
- R&D Institute, ORGANOIDSCIENCES Ltd., Seongnam, 13488, Republic of Korea
| | - Se Rim Choi
- Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
| | - You-Jung Ha
- Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
| | - Yong Seok Choi
- Medical Science Research Institute, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
| | - Woo-Jin Jeong
- Department of Otorhinolaryngology - Head & Neck Surgery, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
- Sensory Organ Research Institute, Seoul National University Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Yun Jong Lee
- Department of Pathology and Translational Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
- Division of Rheumatology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, 13620, Republic of Korea
| | - Kyung Jin Lee
- R&D Institute, ORGANOIDSCIENCES Ltd., Seongnam, 13488, Republic of Korea
| | - Seunghee Cha
- Department of Oral and Maxillofacial Diagnostic Science, Center for Orphaned Autoimmune Disorders, University of Florida College of Dentistry, Gainesville, Florida, 32610, United States of America
| | - Yoosik Kim
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, 34141, Republic of Korea
- Graduate School of Engineering Biology, KAIST, Daejeon, 34141, Republic of Korea
- KAIST Institute for BioCentury (KIB), Daejeon, 34141, Republic of Korea
- KAIST Institute for Health Science and Technology (KIHST), Daejeon 34141, Republic of Korea
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2
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Moitra A, Tiku V, Rapaport D. Yeast mitochondria can process de novo designed β-barrel proteins. FEBS J 2024; 291:292-307. [PMID: 37723586 DOI: 10.1111/febs.16950] [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: 12/29/2022] [Revised: 08/18/2023] [Accepted: 09/04/2023] [Indexed: 09/20/2023]
Abstract
Mitochondrial outer membrane β-barrel proteins are encoded in the nucleus, translated in the cytosol and then targeted to and imported into the respective organelles. Detailed studies have uncovered the mechanisms involved in the import of these proteins and identified the targeting signals and the cytosolic factors that govern their proper biogenesis. Recently, de novo designed eight-stranded β-barrel proteins (Tmb2.3 and Tmb2.17) were shown to fold and assemble into lipid membranes. To better understand the general aspects of the biogenesis of β-barrel proteins, we investigated the fate of these artificial proteins upon their expression in yeast cells. We demonstrate that although these proteins are de novo designed and are not related to bona fide mitochondrial β-barrel proteins, they were targeted to mitochondria and integrated into the organelle outer membrane. We further studied whether this integration requires components of the yeast mitochondrial import machinery like Tom20, Tom70, Tob55/Sam50 and Mas37/Sam37. Whereas it seems that none of the import receptors was required for the biogenesis of the artificial β-barrel proteins, we observed a strong dependency on the TOB/SAM complex. Collectively, our findings demonstrate that the mitochondrial outer membrane is the preferential location in yeast cells for any membrane-embedded β-barrel protein.
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Affiliation(s)
- Anasuya Moitra
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Vitasta Tiku
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
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3
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Genge MG, Roy Chowdhury S, Dohnálek V, Yunoki K, Hirashima T, Endo T, Doležal P, Mokranjac D. Two domains of Tim50 coordinate translocation of proteins across the two mitochondrial membranes. Life Sci Alliance 2023; 6:e202302122. [PMID: 37748811 PMCID: PMC10520260 DOI: 10.26508/lsa.202302122] [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: 04/28/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/27/2023] Open
Abstract
Hundreds of mitochondrial proteins with N-terminal presequences are translocated across the outer and inner mitochondrial membranes via the TOM and TIM23 complexes, respectively. How translocation of proteins across two mitochondrial membranes is coordinated is largely unknown. Here, we show that the two domains of Tim50 in the intermembrane space, named core and PBD, both have essential roles in this process. Building upon the surprising observation that the two domains of Tim50 can complement each other in trans, we establish that the core domain contains the main presequence-binding site and serves as the main recruitment point to the TIM23 complex. On the other hand, the PBD plays, directly or indirectly, a critical role in cooperation of the TOM and TIM23 complexes and supports the receptor function of Tim50. Thus, the two domains of Tim50 both have essential but distinct roles and together coordinate translocation of proteins across two mitochondrial membranes.
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Affiliation(s)
- Marcel G Genge
- Biocenter-Department of Cell Biology, LMU Munich, Munich, Germany
| | | | - Vít Dohnálek
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Kaori Yunoki
- Faculty of Life Sciences and Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
| | - Takashi Hirashima
- Faculty of Life Sciences and Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
| | - Toshiya Endo
- Faculty of Life Sciences and Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan
| | - Pavel Doležal
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Vestec, Czech Republic
| | - Dejana Mokranjac
- Biocenter-Department of Cell Biology, LMU Munich, Munich, Germany
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4
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Prokopchuk G, Butenko A, Dacks JB, Speijer D, Field MC, Lukeš J. Lessons from the deep: mechanisms behind diversification of eukaryotic protein complexes. Biol Rev Camb Philos Soc 2023; 98:1910-1927. [PMID: 37336550 PMCID: PMC10952624 DOI: 10.1111/brv.12988] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 05/30/2023] [Accepted: 06/05/2023] [Indexed: 06/21/2023]
Abstract
Genetic variation is the major mechanism behind adaptation and evolutionary change. As most proteins operate through interactions with other proteins, changes in protein complex composition and subunit sequence provide potentially new functions. Comparative genomics can reveal expansions, losses and sequence divergence within protein-coding genes, but in silico analysis cannot detect subunit substitutions or replacements of entire protein complexes. Insights into these fundamental evolutionary processes require broad and extensive comparative analyses, from both in silico and experimental evidence. Here, we combine data from both approaches and consider the gamut of possible protein complex compositional changes that arise during evolution, citing examples of complete conservation to partial and total replacement by functional analogues. We focus in part on complexes in trypanosomes as they represent one of the better studied non-animal/non-fungal lineages, but extend insights across the eukaryotes by extensive comparative genomic analysis. We argue that gene loss plays an important role in diversification of protein complexes and hence enhancement of eukaryotic diversity.
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Affiliation(s)
- Galina Prokopchuk
- Institute of Parasitology, Biology Centre, Czech Academy of SciencesBranišovská 1160/31České Budějovice37005Czech Republic
- Faculty of ScienceUniversity of South BohemiaBranišovská 1160/31České Budějovice37005Czech Republic
| | - Anzhelika Butenko
- Institute of Parasitology, Biology Centre, Czech Academy of SciencesBranišovská 1160/31České Budějovice37005Czech Republic
- Faculty of ScienceUniversity of South BohemiaBranišovská 1160/31České Budějovice37005Czech Republic
- Life Science Research Centre, Faculty of ScienceUniversity of OstravaChittussiho 983/10Ostrava71000Czech Republic
| | - Joel B. Dacks
- Institute of Parasitology, Biology Centre, Czech Academy of SciencesBranišovská 1160/31České Budějovice37005Czech Republic
- Division of Infectious Diseases, Department of MedicineUniversity of Alberta1‐124 Clinical Sciences Building, 11350‐83 AvenueEdmontonT6G 2R3AlbertaCanada
- Centre for Life's Origins and Evolution, Department of Genetics, Evolution and the EnvironmentUniversity College LondonDarwin Building, Gower StreetLondonWC1E 6BTUK
| | - Dave Speijer
- Medical Biochemistry, Amsterdam UMCUniversity of AmsterdamMeibergdreef 15Amsterdam1105 AZThe Netherlands
| | - Mark C. Field
- Institute of Parasitology, Biology Centre, Czech Academy of SciencesBranišovská 1160/31České Budějovice37005Czech Republic
- School of Life SciencesUniversity of DundeeDow StreetDundeeDD1 5EHScotlandUK
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of SciencesBranišovská 1160/31České Budějovice37005Czech Republic
- Faculty of ScienceUniversity of South BohemiaBranišovská 1160/31České Budějovice37005Czech Republic
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5
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Reed AL, Mitchell W, Alexandrescu AT, Alder NN. Interactions of amyloidogenic proteins with mitochondrial protein import machinery in aging-related neurodegenerative diseases. Front Physiol 2023; 14:1263420. [PMID: 38028797 PMCID: PMC10652799 DOI: 10.3389/fphys.2023.1263420] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/02/2023] [Indexed: 12/01/2023] Open
Abstract
Most mitochondrial proteins are targeted to the organelle by N-terminal mitochondrial targeting sequences (MTSs, or "presequences") that are recognized by the import machinery and subsequently cleaved to yield the mature protein. MTSs do not have conserved amino acid compositions, but share common physicochemical properties, including the ability to form amphipathic α-helical structures enriched with basic and hydrophobic residues on alternating faces. The lack of strict sequence conservation implies that some polypeptides can be mistargeted to mitochondria, especially under cellular stress. The pathogenic accumulation of proteins within mitochondria is implicated in many aging-related neurodegenerative diseases, including Alzheimer's, Parkinson's, and Huntington's diseases. Mechanistically, these diseases may originate in part from mitochondrial interactions with amyloid-β precursor protein (APP) or its cleavage product amyloid-β (Aβ), α-synuclein (α-syn), and mutant forms of huntingtin (mHtt), respectively, that are mediated in part through their associations with the mitochondrial protein import machinery. Emerging evidence suggests that these amyloidogenic proteins may present cryptic targeting signals that act as MTS mimetics and can be recognized by mitochondrial import receptors and transported into different mitochondrial compartments. Accumulation of these mistargeted proteins could overwhelm the import machinery and its associated quality control mechanisms, thereby contributing to neurological disease progression. Alternatively, the uptake of amyloidogenic proteins into mitochondria may be part of a protein quality control mechanism for clearance of cytotoxic proteins. Here we review the pathomechanisms of these diseases as they relate to mitochondrial protein import and effects on mitochondrial function, what features of APP/Aβ, α-syn and mHtt make them suitable substrates for the import machinery, and how this information can be leveraged for the development of therapeutic interventions.
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Affiliation(s)
- Ashley L. Reed
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Wayne Mitchell
- Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, United States
| | - Andrei T. Alexandrescu
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
| | - Nathan N. Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT, United States
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6
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Nashed S, El Barbry H, Benchouaia M, Dijoux-Maréchal A, Delaveau T, Ruiz-Gutierrez N, Gaulier L, Tribouillard-Tanvier D, Chevreux G, Le Crom S, Palancade B, Devaux F, Laine E, Garcia M. Functional mapping of N-terminal residues in the yeast proteome uncovers novel determinants for mitochondrial protein import. PLoS Genet 2023; 19:e1010848. [PMID: 37585488 PMCID: PMC10482271 DOI: 10.1371/journal.pgen.1010848] [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: 11/14/2022] [Revised: 09/06/2023] [Accepted: 06/29/2023] [Indexed: 08/18/2023] Open
Abstract
N-terminal ends of polypeptides are critical for the selective co-translational recruitment of N-terminal modification enzymes. However, it is unknown whether specific N-terminal signatures differentially regulate protein fate according to their cellular functions. In this work, we developed an in-silico approach to detect functional preferences in cellular N-terminomes, and identified in S. cerevisiae more than 200 Gene Ontology terms with specific N-terminal signatures. In particular, we discovered that Mitochondrial Targeting Sequences (MTS) show a strong and specific over-representation at position 2 of hydrophobic residues known to define potential substrates of the N-terminal acetyltransferase NatC. We validated mitochondrial precursors as co-translational targets of NatC by selective purification of translating ribosomes, and found that their N-terminal signature is conserved in Saccharomycotina yeasts. Finally, systematic mutagenesis of the position 2 in a prototypal yeast mitochondrial protein confirmed its critical role in mitochondrial protein import. Our work highlights the hydrophobicity of MTS N-terminal residues and their targeting by NatC as important features for the definition of the mitochondrial proteome, providing a molecular explanation for mitochondrial defects observed in yeast or human NatC-depleted cells. Functional mapping of N-terminal residues thus has the potential to support the discovery of novel mechanisms of protein regulation or targeting.
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Affiliation(s)
- Salomé Nashed
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Houssam El Barbry
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Médine Benchouaia
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Angélie Dijoux-Maréchal
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Thierry Delaveau
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Nadia Ruiz-Gutierrez
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Lucie Gaulier
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | | | | | - Stéphane Le Crom
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | | | - Frédéric Devaux
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Elodie Laine
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
| | - Mathilde Garcia
- Sorbonne Université, CNRS, Institut de Biologie Paris-Seine, UMR 7238, Laboratoire de Biologie Computationnelle et Quantitative, Paris, France
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7
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Makki A, Rehling P. Protein transport along the presequence pathway. Biol Chem 2023; 404:807-812. [PMID: 37155927 DOI: 10.1515/hsz-2023-0133] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 04/25/2023] [Indexed: 05/10/2023]
Abstract
Most mitochondrial proteins are nuclear-encoded and imported by the protein import machinery based on specific targeting signals. The proteins that carry an amino-terminal targeting signal (presequence) are imported via the presequence import pathway that involves the translocases of the outer and inner membranes - TOM and TIM23 complexes. In this article, we discuss how mitochondrial matrix and inner membrane precursor proteins are imported along the presequence pathway in Saccharomyces cerevisiae with a focus on the dynamics of the TIM23 complex, and further update with some of the key findings that advanced the field in the last few years.
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Affiliation(s)
- Abhijith Makki
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, D-37073 Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
- Max Planck Institute for Multidisciplinary Sciences, D-37077 Göttingen, Germany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Göttingen, Germany
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8
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Yang NV, Rogers S, Guerra R, Pagliarini DJ, Theusch E, Krauss RM. TOMM40 and TOMM22 of the Translocase Outer Mitochondrial Membrane Complex rescue statin-impaired mitochondrial dynamics, morphology, and mitophagy in skeletal myotubes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.24.546411. [PMID: 37425714 PMCID: PMC10327005 DOI: 10.1101/2023.06.24.546411] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Background Statins are the drugs most commonly used for lowering plasma low-density lipoprotein (LDL) cholesterol levels and reducing cardiovascular disease risk. Although generally well tolerated, statins can induce myopathy, a major cause of non-adherence to treatment. Impaired mitochondrial function has been implicated as a cause of statin-induced myopathy, but the underlying mechanism remains unclear. We have shown that simvastatin downregulates transcription of TOMM40 and TOMM22 , genes that encode major subunits of the translocase of outer mitochondrial membrane (TOM) complex which is responsible for importing nuclear-encoded proteins and maintaining mitochondrial function. We therefore investigated the role of TOMM40 and TOMM22 in mediating statin effects on mitochondrial function, dynamics, and mitophagy. Methods Cellular and biochemical assays and transmission electron microscopy were used to investigate effects of simvastatin and TOMM40 and TOMM22 expression on measures of mitochondrial function and dynamics in C2C12 and primary human skeletal cell myotubes. Results Knockdown of TOMM40 and TOMM22 in skeletal cell myotubes impaired mitochondrial oxidative function, increased production of mitochondrial superoxide, reduced mitochondrial cholesterol and CoQ levels, disrupted mitochondrial dynamics and morphology, and increased mitophagy, with similar effects resulting from simvastatin treatment. Overexpression of TOMM40 and TOMM22 in simvastatin-treated muscle cells rescued statin effects on mitochondrial dynamics, but not on mitochondrial function or cholesterol and CoQ levels. Moreover, overexpression of these genes resulted in an increase in number and density of cellular mitochondria. Conclusion These results confirm that TOMM40 and TOMM22 are central in regulating mitochondrial homeostasis and demonstrate that downregulation of these genes by statin treatment mediates disruption of mitochondrial dynamics, morphology, and mitophagy, effects that may contribute to statin-induced myopathy. GRAPHICAL ABSTRACT
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9
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Jain N, Gomkale R, Bernhard O, Rehling P, Cruz-Zaragoza LD. A quantitative fluorescence-based approach to study mitochondrial protein import. EMBO Rep 2023; 24:e55760. [PMID: 36938994 PMCID: PMC10157374 DOI: 10.15252/embr.202255760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 01/22/2023] [Accepted: 02/17/2023] [Indexed: 03/21/2023] Open
Abstract
Mitochondria play central roles in cellular energy production and metabolism. Most proteins required to carry out these functions are synthesized in the cytosol and imported into mitochondria. A growing number of metabolic disorders arising from mitochondrial dysfunction can be traced to errors in mitochondrial protein import. The mechanisms underlying the import of precursor proteins are commonly studied using radioactively labeled precursor proteins imported into purified mitochondria. Here, we establish a fluorescence-based import assay to analyze protein import into mitochondria. We show that fluorescently labeled precursors enable import analysis with similar sensitivity to those using radioactive precursors, yet they provide the advantage of quantifying import with picomole resolution. We adapted the import assay to a 96-well plate format allowing for fast analysis in a screening-compatible format. Moreover, we show that fluorescently labeled precursors can be used to monitor the assembly of the F1 F0 ATP synthase in purified mitochondria. Thus, we provide a sensitive fluorescence-based import assay that enables quantitative and fast import analysis.
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Affiliation(s)
- Naintara Jain
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Ridhima Gomkale
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Olaf Bernhard
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.,Max Planck Institute for Multidisciplinary Science, Göttingen, Germany
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10
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Fujimoto S, Fujimaki K, Suzuki T, Katsuma S, Iwanaga M. Expression and localization of Bombyx mori nucleopolyhedrovirus GP37. Virus Genes 2023; 59:457-463. [PMID: 36913065 DOI: 10.1007/s11262-023-01983-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 02/22/2023] [Indexed: 03/14/2023]
Abstract
Mitochondria play an essential role in intracellular energy metabolism. This study described the involvement of Bombyx mori nucleopolyhedrovirus (BmNPV) GP37 (BmGP37) in host mitochondria. Herein, the proteins associated with host mitochondria isolated from BmNPV-infected or mock-infected cells by two-dimensional gel electrophoresis were compared. One mitochondria-associated protein in virus-infected cells was identified as BmGP37 by liquid chromatography-mass spectrometry analysis. Furthermore, the BmGP37 antibodies were generated, which could react specifically with BmGP37 in the BmNPV-infected BmN cells. Western blot experiments showed that BmGP37 was expressed at 18 h post-infection and was verified as a mitochondria-associated protein. Immunofluorescence analysis demonstrated that BmGP37 localized to the host mitochondria during BmNPV infection. Furthermore, western blot analysis revealed that BmGP37 is a novel component protein of the occlusion-derived virus (ODV) of BmNPV. The present results indicated that BmGP37 is one of the ODV-associated proteins and may have important roles in host mitochondria during BmNPV infection.
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Affiliation(s)
- Shota Fujimoto
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Mine-Machi 350, Utsunomiya-Shi, Tochigi, 321-8505, Japan
| | - Kaito Fujimaki
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Mine-Machi 350, Utsunomiya-Shi, Tochigi, 321-8505, Japan
| | - Tomohiro Suzuki
- Center of Bioscience Research and Education, Utsunomiya University, Mine-Machi 350, Utsunomiya-Shi, Tochigi, 321-8505, Japan
| | - Susumu Katsuma
- Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-Ku, Tokyo, 113-8657, Japan
| | - Masashi Iwanaga
- Department of Agrobiology and Bioresources, School of Agriculture, Utsunomiya University, Mine-Machi 350, Utsunomiya-Shi, Tochigi, 321-8505, Japan.
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11
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Sun H, Zheng M, Liu J, Fan W, He H, Huang F. Melatonin promoted osteogenesis of human periodontal ligament cells by regulating mitochondrial functions through the translocase of the outer mitochondrial membrane 20. J Periodontal Res 2023; 58:53-69. [PMID: 36373245 DOI: 10.1111/jre.13068] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 10/08/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND OBJECTIVE Melatonin plays an important role in various beneficial functions, including promoting differentiation. However, effects on osteogenic differentiation, especially in human periodontal cells (hPDLCs), still remain inconclusive. Mitochondria are highly dynamic organelles that play an important role in various biological processes in cells, including energy metabolism and oxidative stress reaction. Furthermore, the translocase of the outer mitochondrial membrane 20 (TOM20) is responsible for recognizing and transporting precursor proteins. Thus, the objective of this study was to evaluate the functionality of melatonin on osteogenesis in human periodontal cells and to explore the involved mechanism of mitochondria. METHODS The hPDLCs were extracted and identified by flow cytometry and multilineage differentiation. We divided hPDLCs into control group, osteogenic induction group, and osteogenesis with melatonin treatment group (100, 10, and 1 μM). Then we used a specific siRNA to achieve interference of TOM20. Alizarin red and Alkaline phosphatase staining and activity assays were performed to evaluate osteogenic differentiation. Osteogenesis-related genes and proteins were measured by qPCR and western blot. Mitochondrial functions were tested using ATP, NAD+/NADH, JC-1, and Seahorse Mito Stress Test kits. Finally, TOM20 and mitochondrial dynamics-related molecules expression were also assessed by qPCR and western blot. RESULTS Our results showed that melatonin-treated hPDLCs had higher calcification and ALP activity as well as upregulated OCN and Runx2 expression at mRNA and protein levels, which was the most obvious in 1 μM melatonin-treated group. Meanwhile, melatonin supplement elevated intracellular ATP production and mitochondrial membrane potential by increasing mitochondrial oxidative metabolism, hence causing a lower NAD+ /NADH ratio. In addition, we also found that melatonin treatment raised TOM20 level and osteogenesis and mitochondrial functions were both suppressed after knocking down TOM20. CONCLUSION We found that melatonin promoted osteogenesis of hPDLCs and 1 μM melatonin had the most remarkable effect. Melatonin treatment can reinforce mitochondrial functions by upregulating TOM20.
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Affiliation(s)
- Haoyun Sun
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Miaomiao Zheng
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Jiawei Liu
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Wenguo Fan
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Hongwen He
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
| | - Fang Huang
- Hospital of Stomatology, Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China
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12
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Shan SO. Role of Hsp70 in Post-Translational Protein Targeting: Tail-Anchored Membrane Proteins and Beyond. Int J Mol Sci 2023; 24:1170. [PMID: 36674686 PMCID: PMC9866221 DOI: 10.3390/ijms24021170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/02/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
The Hsp70 family of molecular chaperones acts as a central 'hub' in the cell that interacts with numerous newly synthesized proteins to assist in their biogenesis. Apart from its central and well-established role in facilitating protein folding, Hsp70s also act as key decision points in the cellular chaperone network that direct client proteins to distinct biogenesis and quality control pathways. In this paper, we review accumulating data that illustrate a new branch in the Hsp70 network: the post-translational targeting of nascent membrane and organellar proteins to diverse cellular organelles. Work in multiple pathways suggests that Hsp70, via its ability to interact with components of protein targeting and translocation machineries, can initiate elaborate substrate relays in a sophisticated cascade of chaperones, cochaperones, and receptor proteins, and thus provide a mechanism to safeguard and deliver nascent membrane proteins to the correct cellular membrane. We discuss the mechanistic principles gleaned from better-studied Hsp70-dependent targeting pathways and outline the observations and outstanding questions in less well-studied systems.
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Affiliation(s)
- Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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13
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Woo S, Moon B, Hwang I. Both metaxin and Tom20 together with two mitochondria-specific motifs support mitochondrial targeting of dual-targeting AtSufE1. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1596-1613. [PMID: 35713200 DOI: 10.1111/jipb.13312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
Plant cells have two endosymbiotic organelles, chloroplasts, and mitochondria. These organelles perform specific functions that depend on organelle-specific proteins. The majority of chloroplast and mitochondrial proteins are specifically imported by the transit peptide and presequence, respectively. However, a significant number of proteins are also dually targeted to these two organelles. Currently, it is not fully understood how proteins are dually targeted to both chloroplasts and mitochondria. In this study, the mechanism underlying mitochondrial targeting of dual targeting AtSufE1 in Arabidopsis was elucidated. The N-terminal fragment containing 80 residues of AtSufE1 (AtSufE1N80) was sufficient to confer dual targeting of reporter protein, AtSufE1N80:GFP, in protoplasts. Two sequence motifs, two arginine residues at 15th and 21st positions, and amino acid (aa) sequence motif AKTLLLRPLK from the 31st to 40th aa position, were responsible for targeting to mitochondria a portion of reporter proteins amid the chloroplast targeting. The sequence motif PSEVPFRRT from the 41st to 50th aa position constitutes a common motif for targeting to both chloroplasts and mitochondria. For mitochondrial import of AtSufE1:N80, Metaxin played a critical role. In addition, BiFC and protein pull-down experiments showed that AtSufE1N80 specifically interacts with import receptors, Metaxin and Tom20. The interaction of AtSufE1N80 with Metaxin was required for the interaction with Tom20. Based on these results, we propose that mitochondrial targeting of dual-targeting AtSufE1 is mediated by both mitochondria-specific and common sequence motifs in the signal sequence through the interaction with import receptors, Metaxin and Tom20, in a successive manner.
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Affiliation(s)
- Seungjin Woo
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - Byeongho Moon
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Korea
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 790-784, Korea
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14
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Structural basis of Tom20 and Tom22 cytosolic domains as the human TOM complex receptors. Proc Natl Acad Sci U S A 2022; 119:e2200158119. [PMID: 35733257 PMCID: PMC9245660 DOI: 10.1073/pnas.2200158119] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mitochondrial preproteins synthesized in cytosol are imported into mitochondria by a multisubunit translocase of the outer membrane (TOM) complex. Functioned as the receptor, the TOM complex components, Tom 20, Tom22, and Tom70, recognize the presequence and further guide the protein translocation. Their deficiency has been linked with neurodegenerative diseases and cardiac pathology. Although several structures of the TOM complex have been reported by cryoelectron microscopy (cryo-EM), how Tom22 and Tom20 function as TOM receptors remains elusive. Here we determined the structure of TOM core complex at 2.53 Å and captured the structure of the TOM complex containing Tom22 and Tom20 cytosolic domains at 3.74 Å. Structural analysis indicates that Tom20 and Tom22 share a similar three-helix bundle structural feature in the cytosolic domain. Further structure-guided biochemical analysis reveals that the Tom22 cytosolic domain is responsible for binding to the presequence, and the helix H1 is critical for this binding. Altogether, our results provide insights into the functional mechanism of the TOM complex recognizing and transferring preproteins across the mitochondrial membrane.
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15
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Popov LD. Mitochondrial-derived vesicles: Recent insights. J Cell Mol Med 2022; 26:3323-3328. [PMID: 35582908 PMCID: PMC9189329 DOI: 10.1111/jcmm.17391] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 04/10/2022] [Accepted: 04/28/2022] [Indexed: 11/25/2022] Open
Abstract
The generation of vesicles is a constitutive attribute of mitochondria inherited from bacterial ancestors. The physiological conditions and mild oxidative stress promote oxidation and dysfunction of certain proteins and lipids within the mitochondrial membranes; these constituents are subsequently packed as small mitochondrial‐derived vesicles (MDVs) (70–150 nm in diameter) and are transported intracellularly to lysosomes and peroxisomes to be degraded. In this way, MDVs remove the damaged mitochondrial components, preserve mitochondrial structural and functional integrity and restore homeostasis. An outline of the current knowledge on MDVs seems to be necessary for understanding the potential impact of this research area in cellular (patho)physiology. The present synopsis is an attempt towards the accomplishment of this demand, highlighting also the still unclear issues related to MDVs. Here, we discuss (i) MDVs budding and generation (molecules and mechanisms), (ii) the distinct cargoes packed and transported by MDVs, (iii) the MDVs trafficking pathways and (iv) the biological role of MDVs, from quality controllers to the involvement in organellar crosstalk, mitochondrial antigen presentation and peroxisome de novo biogenesis. These complex roles uncover also mitochondria integration into the cellular environment. As the therapeutic exploitation of MDVs is currently limited, future insights into MDVs cell biology are expected to direct to novel diagnostic tools and treatments.
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Affiliation(s)
- Lucia-Doina Popov
- "Nicolae Simionescu" Institute of Cellular Biology and Pathology of the Romanian Academy, Bucharest, Romania
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16
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Hoffmann JJ, Becker T. Crosstalk between Mitochondrial Protein Import and Lipids. Int J Mol Sci 2022; 23:ijms23095274. [PMID: 35563660 PMCID: PMC9101885 DOI: 10.3390/ijms23095274] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/29/2022] [Accepted: 05/05/2022] [Indexed: 12/10/2022] Open
Abstract
Mitochondria import about 1000 precursor proteins from the cytosol. The translocase of the outer membrane (TOM complex) forms the major entry site for precursor proteins. Subsequently, membrane-bound protein translocases sort the precursor proteins into the outer and inner membrane, the intermembrane space, and the matrix. The phospholipid composition of mitochondrial membranes is critical for protein import. Structural and biochemical data revealed that phospholipids affect the stability and activity of mitochondrial protein translocases. Integration of proteins into the target membrane involves rearrangement of phospholipids and distortion of the lipid bilayer. Phospholipids are present in the interface between subunits of protein translocases and affect the dynamic coupling of partner proteins. Phospholipids are required for full activity of the respiratory chain to generate membrane potential, which in turn drives protein import across and into the inner membrane. Finally, outer membrane protein translocases are closely linked to organellar contact sites that mediate lipid trafficking. Altogether, intensive crosstalk between mitochondrial protein import and lipid biogenesis controls mitochondrial biogenesis.
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17
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Sayyed UMH, Mahalakshmi R. Mitochondrial protein translocation machinery: From TOM structural biogenesis to functional regulation. J Biol Chem 2022; 298:101870. [PMID: 35346689 PMCID: PMC9052162 DOI: 10.1016/j.jbc.2022.101870] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 03/13/2022] [Accepted: 03/14/2022] [Indexed: 01/15/2023] Open
Abstract
The human mitochondrial outer membrane is biophysically unique as it is the only membrane possessing transmembrane β-barrel proteins (mitochondrial outer membrane proteins, mOMPs) in the cell. The most vital of the three mOMPs is the core protein of the translocase of the outer mitochondrial membrane (TOM) complex. Identified first as MOM38 in Neurospora in 1990, the structure of Tom40, the core 19-stranded β-barrel translocation channel, was solved in 2017, after nearly three decades. Remarkably, the past four years have witnessed an exponential increase in structural and functional studies of yeast and human TOM complexes. In addition to being conserved across all eukaryotes, the TOM complex is the sole ATP-independent import machinery for nearly all of the ∼1000 to 1500 known mitochondrial proteins. Recent cryo-EM structures have provided detailed insight into both possible assembly mechanisms of the TOM core complex and organizational dynamics of the import machinery and now reveal novel regulatory interplay with other mOMPs. Functional characterization of the TOM complex using biochemical and structural approaches has also revealed mechanisms for substrate recognition and at least five defined import pathways for precursor proteins. In this review, we discuss the discovery, recently solved structures, molecular function, and regulation of the TOM complex and its constituents, along with the implications these advances have for alleviating human diseases.
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Affiliation(s)
- Ulfat Mohd Hanif Sayyed
- Molecular Biophysics Laboratory, Indian Institute of Science Education and Research, Bhopal, India
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18
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Song J, Becker T. Fidelity of organellar protein targeting. Curr Opin Cell Biol 2022; 75:102071. [DOI: 10.1016/j.ceb.2022.02.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/07/2022] [Accepted: 02/09/2022] [Indexed: 11/26/2022]
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19
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Araiso Y, Imai K, Endo T. Role of the TOM Complex in Protein Import into Mitochondria: Structural Views. Annu Rev Biochem 2022; 91:679-703. [PMID: 35287471 DOI: 10.1146/annurev-biochem-032620-104527] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mitochondria are central to energy production, metabolism and signaling, and apoptosis. To make new mitochondria from preexisting mitochondria, the cell needs to import mitochondrial proteins from the cytosol into the mitochondria with the aid of translocators in the mitochondrial membranes. The translocase of the outer membrane (TOM) complex, an outer membrane translocator, functions as an entry gate for most mitochondrial proteins. Although high-resolution structures of the receptor subunits of the TOM complex were deposited in the early 2000s, those of entire TOM complexes became available only in 2019. The structural details of these TOM complexes, consisting of the dimer of the β-barrel import channel Tom40 and four α-helical membrane proteins, revealed the presence of several distinct paths and exits for the translocation of over 1,000 different mitochondrial precursor proteins. High-resolution structures of TOM complexes now open up a new era of studies on the structures, functions, and dynamics of the mitochondrial import system. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Yuhei Araiso
- Department of Clinical Laboratory Science, Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, Kanazawa, Ishikawa, Japan
| | - Kenichiro Imai
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, 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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20
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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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21
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Zhao F, Zou MH. Role of the Mitochondrial Protein Import Machinery and Protein Processing in Heart Disease. Front Cardiovasc Med 2021; 8:749756. [PMID: 34651031 PMCID: PMC8505727 DOI: 10.3389/fcvm.2021.749756] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria are essential organelles for cellular energy production, metabolic homeostasis, calcium homeostasis, cell proliferation, and apoptosis. About 99% of mammalian mitochondrial proteins are encoded by the nuclear genome, synthesized as precursors in the cytosol, and imported into mitochondria by mitochondrial protein import machinery. Mitochondrial protein import systems function not only as independent units for protein translocation, but also are deeply integrated into a functional network of mitochondrial bioenergetics, protein quality control, mitochondrial dynamics and morphology, and interaction with other organelles. Mitochondrial protein import deficiency is linked to various diseases, including cardiovascular disease. In this review, we describe an emerging class of protein or genetic variations of components of the mitochondrial import machinery involved in heart disease. The major protein import pathways, including the presequence pathway (TIM23 pathway), the carrier pathway (TIM22 pathway), and the mitochondrial intermembrane space import and assembly machinery, related translocases, proteinases, and chaperones, are discussed here. This review highlights the importance of mitochondrial import machinery in heart disease, which deserves considerable attention, and further studies are urgently needed. Ultimately, this knowledge may be critical for the development of therapeutic strategies in heart disease.
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Affiliation(s)
- Fujie Zhao
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, United States
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22
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Geldon S, Fernández-Vizarra E, Tokatlidis K. Redox-Mediated Regulation of Mitochondrial Biogenesis, Dynamics, and Respiratory Chain Assembly in Yeast and Human Cells. Front Cell Dev Biol 2021; 9:720656. [PMID: 34557489 PMCID: PMC8452992 DOI: 10.3389/fcell.2021.720656] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/04/2021] [Indexed: 12/24/2022] Open
Abstract
Mitochondria are double-membrane organelles that contain their own genome, the mitochondrial DNA (mtDNA), and reminiscent of its endosymbiotic origin. Mitochondria are responsible for cellular respiration via the function of the electron oxidative phosphorylation system (OXPHOS), located in the mitochondrial inner membrane and composed of the four electron transport chain (ETC) enzymes (complexes I-IV), and the ATP synthase (complex V). Even though the mtDNA encodes essential OXPHOS components, the large majority of the structural subunits and additional biogenetical factors (more than seventy proteins) are encoded in the nucleus and translated in the cytoplasm. To incorporate these proteins and the rest of the mitochondrial proteome, mitochondria have evolved varied, and sophisticated import machineries that specifically target proteins to the different compartments defined by the two membranes. The intermembrane space (IMS) contains a high number of cysteine-rich proteins, which are mostly imported via the MIA40 oxidative folding system, dependent on the reduction, and oxidation of key Cys residues. Several of these proteins are structural components or assembly factors necessary for the correct maturation and function of the ETC complexes. Interestingly, many of these proteins are involved in the metalation of the active redox centers of complex IV, the terminal oxidase of the mitochondrial ETC. Due to their function in oxygen reduction, mitochondria are the main generators of reactive oxygen species (ROS), on both sides of the inner membrane, i.e., in the matrix and the IMS. ROS generation is important due to their role as signaling molecules, but an excessive production is detrimental due to unwanted oxidation reactions that impact on the function of different types of biomolecules contained in mitochondria. Therefore, the maintenance of the redox balance in the IMS is essential for mitochondrial function. In this review, we will discuss the role that redox regulation plays in the maintenance of IMS homeostasis as well as how mitochondrial ROS generation may be a key regulatory factor for ETC biogenesis, especially for complex IV.
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Affiliation(s)
| | - Erika Fernández-Vizarra
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kostas Tokatlidis
- Institute of Molecular Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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23
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Moitra A, Rapaport D. The Biogenesis Process of VDAC - From Early Cytosolic Events to Its Final Membrane Integration. Front Physiol 2021; 12:732742. [PMID: 34456757 PMCID: PMC8388839 DOI: 10.3389/fphys.2021.732742] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/26/2021] [Indexed: 11/13/2022] Open
Abstract
Voltage dependent anion-selective channel (VDAC) is the most abundant protein in the mitochondrial outer membrane. It is a membrane embedded β-barrel protein composed of 19 mostly anti-parallel β-strands that form a hydrophilic pore. Similar to the vast majority of mitochondrial proteins, VDAC is encoded by nuclear DNA, and synthesized on cytosolic ribosomes. The protein is then targeted to the mitochondria while being maintained in an import competent conformation by specific cytosolic factors. Recent studies, using yeast cells as a model system, have unearthed the long searched for mitochondrial targeting signal for VDAC and the role of cytosolic chaperones and mitochondrial import machineries in its proper biogenesis. In this review, we summarize our current knowledge regarding the early cytosolic stages of the biogenesis of VDAC molecules, the specific targeting of VDAC to the mitochondrial surface, and the subsequent integration of VDAC into the mitochondrial outer membrane by the TOM and TOB/SAM complexes.
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Affiliation(s)
- Anasuya Moitra
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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24
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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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25
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Friedlander JE, Shen N, Zeng A, Korm S, Feng H. Failure to Guard: Mitochondrial Protein Quality Control in Cancer. Int J Mol Sci 2021; 22:ijms22158306. [PMID: 34361072 PMCID: PMC8348654 DOI: 10.3390/ijms22158306] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/20/2021] [Accepted: 07/27/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are energetic and dynamic organelles with a crucial role in bioenergetics, metabolism, and signaling. Mitochondrial proteins, encoded by both nuclear and mitochondrial DNA, must be properly regulated to ensure proteostasis. Mitochondrial protein quality control (MPQC) serves as a critical surveillance system, employing different pathways and regulators as cellular guardians to ensure mitochondrial protein quality and quantity. In this review, we describe key pathways and players in MPQC, such as mitochondrial protein translocation-associated degradation, mitochondrial stress responses, chaperones, and proteases, and how they work together to safeguard mitochondrial health and integrity. Deregulated MPQC leads to proteotoxicity and dysfunctional mitochondria, which contributes to numerous human diseases, including cancer. We discuss how alterations in MPQC components are linked to tumorigenesis, whether they act as drivers, suppressors, or both. Finally, we summarize recent advances that seek to target these alterations for the development of anti-cancer drugs.
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Affiliation(s)
- Joseph E. Friedlander
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Ning Shen
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
| | - Aozhuo Zeng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Sovannarith Korm
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
| | - Hui Feng
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, USA; (J.E.F.); (N.S.); (A.Z.); (S.K.)
- Department of Medicine, Section of Hematology and Medical Oncology, Boston University School of Medicine, Boston, MA 02118, USA
- Correspondence: ; Tel.: +1-617-358-4688; Fax: +1-617-358-1599
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26
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Davis MM, Lamichhane R, Bruce BD. Elucidating Protein Translocon Dynamics with Single-Molecule Precision. Trends Cell Biol 2021; 31:569-583. [PMID: 33865650 DOI: 10.1016/j.tcb.2021.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/28/2023]
Abstract
Translocons are protein assemblies that facilitate the targeting and transport of proteins into and across biological membranes. Our understanding of these systems has been advanced using genetics, biochemistry, and structural biology. Despite these classic advances, until recently we have still largely lacked a detailed understanding of how translocons recognize and facilitate protein translocation. With the advent and improvements of cryogenic electron microscopy (cryo-EM) single-particle analysis and single-molecule fluorescence microscopy, the details of how translocons function are finally emerging. Here, we introduce these methods and evaluate their importance in understanding translocon structure, function, and dynamics.
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Affiliation(s)
- Madeline M Davis
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
| | - Rajan Lamichhane
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA
| | - Barry D Bruce
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Department of Microbiology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Graduate Program in Genome Science and Technology, University of Tennessee at Knoxville, Knoxville, TN 37996, USA; Chemical and Biomolecular Engineering, University of Tennessee at Knoxville, Knoxville, TN 37996, USA.
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27
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Grevel A, Becker T. Porins as helpers in mitochondrial protein translocation. Biol Chem 2021; 401:699-708. [PMID: 31967957 DOI: 10.1515/hsz-2019-0438] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 01/15/2020] [Indexed: 12/22/2022]
Abstract
Mitochondria import the vast majority of their proteins via dedicated protein machineries. The translocase of the outer membrane (TOM complex) forms the main entry site for precursor proteins that are produced on cytosolic ribosomes. Subsequently, different protein sorting machineries transfer the incoming preproteins to the mitochondrial outer and inner membranes, the intermembrane space, and the matrix. In this review, we highlight the recently discovered role of porin, also termed voltage-dependent anion channel (VDAC), in mitochondrial protein biogenesis. Porin forms the major channel for metabolites and ions in the outer membrane of mitochondria. Two different functions of porin in protein translocation have been reported. First, it controls the formation of the TOM complex by modulating the integration of the central receptor Tom22 into the mature translocase. Second, porin promotes the transport of carrier proteins toward the carrier translocase (TIM22 complex), which inserts these preproteins into the inner membrane. Therefore, porin acts as a coupling factor to spatially coordinate outer and inner membrane transport steps. Thus, porin links metabolite transport to protein import, which are both essential for mitochondrial function and biogenesis.
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Affiliation(s)
- Alexander Grevel
- Institute of Biochemistry und Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry und Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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28
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Terada K, Gimenez-Dejoz J, Kurita T, Oikawa K, Uji H, Tsuchiya K, Numata K. Synthetic Mitochondria-Targeting Peptides Incorporating α-Aminoisobutyric Acid with a Stable Amphiphilic Helix Conformation in Plant Cells. ACS Biomater Sci Eng 2021; 7:1475-1484. [PMID: 33606492 DOI: 10.1021/acsbiomaterials.0c01533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the genetic modification of plant cells, the mitochondrion is an important target in addition to the nucleus and plastid. However, gene delivery into the mitochondria of plant cells has yet to be established by conventional methods, such as particle bombardment, because of the small size and high mobility of mitochondria. To develop an efficient mitochondria-targeting signal (MTS) that functions in plant cells, we designed the artificial peptide (LURL)3 and its analogues, which periodically feature hydrophobic α-aminoisobutyric acid (Aib, U) and cationic arginine (R), considering the consensus motif recognized by the mitochondrial import receptor Tom20. Circular dichroism measurements and molecular dynamics simulation studies revealed that (LURL)3 had a propensity to form a stable α-helix in 0.1 M phosphate buffer solution containing 1.0 wt % sodium dodecyl sulfate. After internalization into plant cells via particle bombardment, (LURL)3 revealed highly selective accumulation in the mitochondria, whereas its analogue (LARL)3 was predominantly located in the vacuoles in addition to mitochondria. The high selectivity of (LURL)3 can be attributed to the incorporation of Aib, which promotes the hydrophobic interaction between the MTS and Tom20 by increasing the hydrophobicity and helicity of (LURL)3. The present study provided a prospective mitochondrial targeting system using the simple design of artificial peptides.
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Affiliation(s)
- Kayo Terada
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Joan Gimenez-Dejoz
- Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Taichi Kurita
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kazusato Oikawa
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Hirotaka Uji
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kousuke Tsuchiya
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Keiji Numata
- Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto Daigaku Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.,Biomacromolecules Research Team, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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29
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Latorre-Muro P, O'Malley KE, Bennett CF, Perry EA, Balsa E, Tavares CDJ, Jedrychowski M, Gygi SP, Puigserver P. A cold-stress-inducible PERK/OGT axis controls TOM70-assisted mitochondrial protein import and cristae formation. Cell Metab 2021; 33:598-614.e7. [PMID: 33592173 PMCID: PMC7962155 DOI: 10.1016/j.cmet.2021.01.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 11/20/2020] [Accepted: 01/13/2021] [Indexed: 12/14/2022]
Abstract
The architecture of cristae provides a spatial mitochondrial organization that contains functional respiratory complexes. Several protein components including OPA1 and MICOS complex subunits organize cristae structure, but upstream regulatory mechanisms are largely unknown. Here, in vivo and in vitro reconstitution experiments show that the endoplasmic reticulum (ER) kinase PERK promotes cristae formation by increasing TOM70-assisted mitochondrial import of MIC19, a critical subunit of the MICOS complex. Cold stress or β-adrenergic stimulation activates PERK that phosphorylates O-linked N-acetylglucosamine transferase (OGT). Phosphorylated OGT glycosylates TOM70 on Ser94, enhancing MIC19 protein import into mitochondria and promoting cristae formation and respiration. In addition, PERK-activated OGT O-GlcNAcylates and attenuates CK2α activity, which mediates TOM70 Ser94 phosphorylation and decreases MIC19 mitochondrial protein import. We have identified a cold-stress inter-organelle PERK-OGT-TOM70 axis that increases cell respiration through mitochondrial protein import and subsequent cristae formation. These studies have significant implications in cellular bioenergetics and adaptations to stress conditions.
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Affiliation(s)
- Pedro Latorre-Muro
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Katherine E O'Malley
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Christopher F Bennett
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Elizabeth A Perry
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Eduardo Balsa
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Clint D J Tavares
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Mark Jedrychowski
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02215, USA.
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30
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Beiersdorf J, Hevesi Z, Calvigioni D, Pyszkowski J, Romanov R, Szodorai E, Lubec G, Shirran S, Botting CH, Kasper S, Guy GW, Gray R, Di Marzo V, Harkany T, Keimpema E. Adverse effects of Δ9-tetrahydrocannabinol on neuronal bioenergetics during postnatal development. JCI Insight 2020; 5:135418. [PMID: 33141759 PMCID: PMC7714410 DOI: 10.1172/jci.insight.135418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 10/28/2020] [Indexed: 11/22/2022] Open
Abstract
Ongoing societal changes in views on the medical and recreational roles of cannabis increased the use of concentrated plant extracts with a Δ9-tetrahydrocannabinol (THC) content of more than 90%. Even though prenatal THC exposure is widely considered adverse for neuronal development, equivalent experimental data for young age cohorts are largely lacking. Here, we administered plant-derived THC (1 or 5 mg/kg) to mice daily during P5–P16 and P5–P35 and monitored its effects on hippocampal neuronal survival and specification by high-resolution imaging and iTRAQ proteomics, respectively. We found that THC indiscriminately affects pyramidal cells and both cannabinoid receptor 1+ (CB1R)+ and CB1R– interneurons by P16. THC particularly disrupted the expression of mitochondrial proteins (complexes I–IV), a change that had persisted even 4 months after the end of drug exposure. This was reflected by a THC-induced loss of membrane integrity occluding mitochondrial respiration and could be partially or completely rescued by pH stabilization, antioxidants, bypassed glycolysis, and targeting either mitochondrial soluble adenylyl cyclase or the mitochondrial voltage-dependent anion channel. Overall, THC exposure during infancy induces significant and long-lasting reorganization of neuronal circuits through mechanisms that, in large part, render cellular bioenergetics insufficient to sustain key developmental processes in otherwise healthy neurons. Repeated THC exposure in juvenile mice compromises the limbic circuitry, with life-long impairment to the respiration of neurons.
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Affiliation(s)
- Johannes Beiersdorf
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Zsofia Hevesi
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Daniela Calvigioni
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | | | - Roman Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Edit Szodorai
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
| | - Gert Lubec
- Paracelsus Private Medical University, Salzburg, Austria
| | - Sally Shirran
- School of Chemistry, University of St. Andrews, St. Andrews, United Kingdom
| | | | - Siegfried Kasper
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | | | - Roy Gray
- GW Phamaceuticals, Salisbury, Wiltshire, United Kingdom
| | - Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Pozzuoli, Italy.,Canada Excellence Research Chair, Institut Universitaire de Cardiologie et de Pneumologie de Québec and Institut sur la Nutrition et les Aliments Fonctionnels, Université Laval, Québec, Québec, Canada
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria.,Department of Neuroscience, Biomedikum D7, Karolinska Institutet, Solna, Sweden
| | - Erik Keimpema
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, Vienna, Austria
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31
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Gupta A, Becker T. Mechanisms and pathways of mitochondrial outer membrane protein biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1862:148323. [PMID: 33035511 DOI: 10.1016/j.bbabio.2020.148323] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 11/29/2022]
Abstract
Outer membrane proteins integrate mitochondria into the cellular environment. They warrant exchange of small molecules like metabolites and ions, transport proteins into mitochondria, form contact sites to other cellular organelles for lipid exchange, constitute a signaling platform for apoptosis and inflammation and mediate organelle fusion and fission. The outer membrane contains two types of integral membrane proteins. Proteins with a transmembrane β-barrel structure and proteins with a single or multiple α-helical membrane spans. All outer membrane proteins are produced on cytosolic ribosomes and imported into the target organelle. Precursors of β-barrel and α-helical proteins are transported into the outer membrane via distinct import routes. The translocase of the outer membrane (TOM complex) transports β-barrel precursors across the outer membrane and the sorting and assembly machinery (SAM complex) inserts them into the target membrane. The mitochondrial import (MIM) complex constitutes the major integration site for α-helical embedded proteins. The import of some MIM-substrates involves TOM receptors, while others are imported in a TOM-independent manner. Remarkably, TOM, SAM and MIM complexes dynamically interact to import a large set of different proteins and to coordinate their assembly into protein complexes. Thus, protein import into the mitochondrial outer membrane involves a dynamic platform of protein translocases.
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Affiliation(s)
- Arushi Gupta
- Institut für Biochemie und Molekularbiologie, ZBMZ, Universität Freiburg, 79104 Freiburg, Germany
| | - Thomas Becker
- Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Universität Bonn, Nussallee 11, 53115 Bonn, Germany.
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32
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Wang W, Chen X, Zhang L, Yi J, Ma Q, Yin J, Zhuo W, Gu J, Yang M. Atomic structure of human TOM core complex. Cell Discov 2020; 6:67. [PMID: 33083003 PMCID: PMC7522991 DOI: 10.1038/s41421-020-00198-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/20/2020] [Indexed: 12/22/2022] Open
Abstract
The translocase of the outer mitochondrial membrane (TOM) complex is the main entry gate for mitochondrial precursor proteins synthesized on cytosolic ribosomes. Here we report the single-particle cryo-electron microscopy (cryo-EM) structure of the dimeric human TOM core complex (TOM-CC). Two Tom40 β-barrel proteins, connected by two Tom22 receptor subunits and one phospholipid, form the protein-conducting channels. The small Tom proteins Tom5, Tom6, and Tom7 surround the channel and have notable configurations. The distinct electrostatic features of the complex, including the pronounced negative interior and the positive regions at the periphery and center of the dimer on the intermembrane space (IMS) side, provide insight into the preprotein translocation mechanism. Further, two dimeric TOM complexes may associate to form tetramer in the shape of a parallelogram, offering a potential explanation into the unusual structural features of Tom subunits and a new perspective of viewing the import of mitochondrial proteins.
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Affiliation(s)
- Wenhe Wang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Xudong Chen
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jingbo Yi
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Qingxi Ma
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jian Yin
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Wei Zhuo
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Jinke Gu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology & Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084 Beijing, China
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030 Hubei China
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33
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Grevel A, Pfanner N, Becker T. Coupling of import and assembly pathways in mitochondrial protein biogenesis. Biol Chem 2020; 401:117-129. [PMID: 31513529 DOI: 10.1515/hsz-2019-0310] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 08/13/2019] [Indexed: 12/14/2022]
Abstract
Biogenesis and function of mitochondria depend on the import of about 1000 precursor proteins that are produced on cytosolic ribosomes. The translocase of the outer membrane (TOM) forms the entry gate for most proteins. After passage through the TOM channel, dedicated preprotein translocases sort the precursor proteins into the mitochondrial subcompartments. Many proteins have to be assembled into oligomeric membrane-integrated complexes in order to perform their functions. In this review, we discuss a dual role of mitochondrial preprotein translocases in protein translocation and oligomeric assembly, focusing on the biogenesis of the TOM complex and the respiratory chain. The sorting and assembly machinery (SAM) of the outer mitochondrial membrane forms a dynamic platform for coupling transport and assembly of TOM subunits. The biogenesis of the cytochrome c oxidase of the inner membrane involves a molecular circuit to adjust translation of mitochondrial-encoded core subunits to the availability of nuclear-encoded partner proteins. Thus, mitochondrial protein translocases not only import precursor proteins but can also support their assembly into functional complexes.
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Affiliation(s)
- Alexander Grevel
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,Faculty of Biology, University of Freiburg, D-79104 Freiburg, Germany
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Thomas Becker
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, D-79104 Freiburg, Germany.,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, D-79104 Freiburg, Germany
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34
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Cytosolic Events in the Biogenesis of Mitochondrial Proteins. Trends Biochem Sci 2020; 45:650-667. [DOI: 10.1016/j.tibs.2020.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 03/18/2020] [Accepted: 04/02/2020] [Indexed: 01/08/2023]
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35
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Horten P, Colina-Tenorio L, Rampelt H. Biogenesis of Mitochondrial Metabolite Carriers. Biomolecules 2020; 10:E1008. [PMID: 32645990 PMCID: PMC7408425 DOI: 10.3390/biom10071008] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/02/2020] [Accepted: 07/03/2020] [Indexed: 12/28/2022] Open
Abstract
: Metabolite carriers of the mitochondrial inner membrane are crucial for cellular physiology since mitochondria contribute essential metabolic reactions and synthesize the majority of the cellular ATP. Like almost all mitochondrial proteins, carriers have to be imported into mitochondria from the cytosol. Carrier precursors utilize a specialized translocation pathway dedicated to the biogenesis of carriers and related proteins, the carrier translocase of the inner membrane (TIM22) pathway. After recognition and import through the mitochondrial outer membrane via the translocase of the outer membrane (TOM) complex, carrier precursors are ushered through the intermembrane space by hexameric TIM chaperones and ultimately integrated into the inner membrane by the TIM22 carrier translocase. Recent advances have shed light on the mechanisms of TOM translocase and TIM chaperone function, uncovered an unexpected versatility of the machineries, and revealed novel components and functional crosstalk of the human TIM22 translocase.
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Affiliation(s)
- Patrick Horten
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Lilia Colina-Tenorio
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
| | - Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany; (P.H.); (L.C.-T.)
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany
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36
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Avendaño-Monsalve MC, Ponce-Rojas JC, Funes S. From cytosol to mitochondria: the beginning of a protein journey. Biol Chem 2020; 401:645-661. [DOI: 10.1515/hsz-2020-0110] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 02/24/2020] [Indexed: 01/18/2023]
Abstract
AbstractMitochondrial protein import is one of the key processes during mitochondrial biogenesis that involves a series of events necessary for recognition and delivery of nucleus-encoded/cytosol-synthesized mitochondrial proteins into the organelle. The past research efforts have mainly unraveled how membrane translocases ensure the correct protein sorting within the different mitochondrial subcompartments. However, early steps of recognition and delivery remain relatively uncharacterized. In this review, we discuss our current understanding about the signals on mitochondrial proteins, as well as in the mRNAs encoding them, which with the help of cytosolic chaperones and membrane receptors support protein targeting to the organelle in order to avoid improper localization. In addition, we discuss recent findings that illustrate how mistargeting of mitochondrial proteins triggers stress responses, aiming to restore cellular homeostasis.
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Affiliation(s)
- Maria Clara Avendaño-Monsalve
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
| | - José Carlos Ponce-Rojas
- Department of Molecular, Cellular, and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106-9625, USA
| | - Soledad Funes
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Circuito Exterior s/n Ciudad Universitaria Coyoacán, México, Cd.Mx. 04510, Mexico
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37
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Abstract
Mitochondria are essential organelles in eukaryotes. Most mitochondrial proteins are encoded by the nuclear genome and translated in the cytosol. Nuclear-encoded mitochondrial proteins need to be imported, processed, folded, and assembled into their functional states. To maintain protein homeostasis (proteostasis), mitochondria are equipped with a distinct set of quality control machineries. Deficiencies in such systems lead to mitochondrial dysfunction, which is a hallmark of aging and many human diseases, such as neurodegenerative diseases, cardiovascular diseases, and cancer. In this review, we discuss the unique challenges and solutions of proteostasis in mitochondria. The import machinery coordinates with mitochondrial proteases and chaperones to maintain the mitochondrial proteome. Moreover, mitochondrial proteostasis depends on cytosolic protein quality control mechanisms during crises. In turn, mitochondria facilitate cytosolic proteostasis. Increasing evidence suggests that enhancing mitochondrial proteostasis may hold therapeutic potential to protect against protein aggregation-associated cellular defects.
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Affiliation(s)
- Linhao Ruan
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Yuhao Wang
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Xi Zhang
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Alexis Tomaszewski
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Joshua T McNamara
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Biochemistry, Cellular and Molecular Biology (BCMB) Graduate Program, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
| | - Rong Li
- Center for Cell Dynamics, Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA; , , , , ,
- Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
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38
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Rampelt H, Sucec I, Bersch B, Horten P, Perschil I, Martinou JC, van der Laan M, Wiedemann N, Schanda P, Pfanner N. The mitochondrial carrier pathway transports non-canonical substrates with an odd number of transmembrane segments. BMC Biol 2020; 18:2. [PMID: 31907035 PMCID: PMC6945462 DOI: 10.1186/s12915-019-0733-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The mitochondrial pyruvate carrier (MPC) plays a central role in energy metabolism by transporting pyruvate across the inner mitochondrial membrane. Its heterodimeric composition and homology to SWEET and semiSWEET transporters set the MPC apart from the canonical mitochondrial carrier family (named MCF or SLC25). The import of the canonical carriers is mediated by the carrier translocase of the inner membrane (TIM22) pathway and is dependent on their structure, which features an even number of transmembrane segments and both termini in the intermembrane space. The import pathway of MPC proteins has not been elucidated. The odd number of transmembrane segments and positioning of the N-terminus in the matrix argues against an import via the TIM22 carrier pathway but favors an import via the flexible presequence pathway. RESULTS Here, we systematically analyzed the import pathways of Mpc2 and Mpc3 and report that, contrary to an expected import via the flexible presequence pathway, yeast MPC proteins with an odd number of transmembrane segments and matrix-exposed N-terminus are imported by the carrier pathway, using the receptor Tom70, small TIM chaperones, and the TIM22 complex. The TIM9·10 complex chaperones MPC proteins through the mitochondrial intermembrane space using conserved hydrophobic motifs that are also required for the interaction with canonical carrier proteins. CONCLUSIONS The carrier pathway can import paired and non-paired transmembrane helices and translocate N-termini to either side of the mitochondrial inner membrane, revealing an unexpected versatility of the mitochondrial import pathway for non-cleavable inner membrane proteins.
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Affiliation(s)
- Heike Rampelt
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.
| | - Iva Sucec
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 38000, Grenoble, France
| | - Beate Bersch
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 38000, Grenoble, France
| | - Patrick Horten
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Inge Perschil
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
| | | | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Saarland University, 66421 Homburg, Germany
| | - Nils Wiedemann
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany
| | - Paul Schanda
- Institut de Biologie Structurale (IBS), Univ. Grenoble Alpes, CEA, CNRS, 38000, Grenoble, France
| | - Nikolaus Pfanner
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.
- CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.
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Tucker K, Park E. Cryo-EM structure of the mitochondrial protein-import channel TOM complex at near-atomic resolution. Nat Struct Mol Biol 2019; 26:1158-1166. [PMID: 31740857 DOI: 10.1038/s41594-019-0339-2] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/23/2019] [Indexed: 11/09/2022]
Abstract
Nearly all mitochondrial proteins are encoded by the nuclear genome and imported into mitochondria after synthesis on cytosolic ribosomes. These precursor proteins are translocated into mitochondria by the TOM complex, a protein-conducting channel in the mitochondrial outer membrane. We have determined high-resolution cryo-EM structures of the core TOM complex from Saccharomyces cerevisiae in dimeric and tetrameric forms. Dimeric TOM consists of two copies each of five proteins arranged in two-fold symmetry: pore-forming β-barrel protein Tom40 and four auxiliary α-helical transmembrane proteins. The pore of each Tom40 has an overall negatively charged inner surface attributed to multiple functionally important acidic patches. The tetrameric complex is essentially a dimer of dimeric TOM, which may be capable of forming higher-order oligomers. Our study reveals the detailed molecular organization of the TOM complex and provides new insights about the mechanism of protein translocation into mitochondria.
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Affiliation(s)
- Kyle Tucker
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Eunyong Park
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA. .,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA.
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40
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Acar DD, Stroobants VJE, Favoreel H, Saelens X, Nauwynck HJ. Identification of peptide domains involved in the subcellular localization of the feline coronavirus 3b protein. J Gen Virol 2019; 100:1417-1430. [PMID: 31483243 PMCID: PMC7079696 DOI: 10.1099/jgv.0.001321] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Feline coronavirus (FCoV) has been identified as the aetiological agent of feline infectious peritonitis (FIP), a highly fatal systemic disease in cats. FCoV open reading frame 3 (ORF3) encodes accessory proteins 3a, 3b and 3 c. The FCoV 3b accessory protein consists of 72 amino acid residues and localizes to nucleoli and mitochondria. The present work focused on peptide domains within FCoV 3b that drive its intracellular trafficking. Transfection of different cell types with FCoV 3b fused to enhanced green fluorescent protein (EGFP) or 3×FLAG confirmed localization of FCoV 3b in the mitochondria and nucleoli. Using serial truncated mutants, we showed that nucleolar accumulation is controlled by a joint nucleolar and nuclear localization signal (NoLS/NLS) in which the identified overlapping pat4 motifs (residues 53–57) play a critical role. Mutational analysis also revealed that mitochondrial translocation is mediated by N-terminal residues 10–35, in which a Tom20 recognition motif (residues 13–17) and two other overlapping hexamers (residues 24–30) associated with mitochondrial targeting were identified. In addition, a second Tom20 recognition motif was identified further downstream (residues 61–65), although the mitochondrial translocation evoked by these residues seemed less efficient as a diffuse cytoplasmic distribution was also observed. Assessing the spatiotemporal distribution of FCoV 3b did not provide convincing evidence of dynamic shuttling behaviour between the nucleoli and the mitochondria.
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Affiliation(s)
- Delphine D. Acar
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Veerle J. E. Stroobants
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Herman Favoreel
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Xavier Saelens
- VIB-UGent Center for Medical Biotechnology, VIB, Ghent, Belgium; Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Hans J. Nauwynck
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- *Correspondence: Hans J. Nauwynck,
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41
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Lee DW, Lee S, Lee J, Woo S, Razzak MA, Vitale A, Hwang I. Molecular Mechanism of the Specificity of Protein Import into Chloroplasts and Mitochondria in Plant Cells. MOLECULAR PLANT 2019; 12:951-966. [PMID: 30890495 DOI: 10.1016/j.molp.2019.03.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 02/19/2019] [Accepted: 03/10/2019] [Indexed: 05/04/2023]
Abstract
Plants possess both types of endosymbiotic organelles, chloroplasts and mitochondria. Transit peptides and presequences function as signal sequences for specific import into chloroplasts and mitochondria, respectively. However, how these highly similar signal sequences confer the protein import specificity remains elusive. Here, we show that mitochondrial- or chloroplast-specific import involves two distinct steps, specificity determination and translocation across envelopes, which are mediated by the N-terminal regions and functionally interchangeable C-terminal regions, respectively, of transit peptides and presequences. A domain harboring multiple-arginine and hydrophobic sequence motifs in the N-terminal regions of presequences was identified as the mitochondrial specificity factor. The presence of this domain and the absence of arginine residues in the N-terminal regions of otherwise common targeting signals confers specificity of protein import into mitochondria and chloroplasts, respectively. AtToc159, a chloroplast import receptor, also contributes to determining chloroplast import specificity. We propose that common ancestral sequences were functionalized into mitochondrial- and chloroplast-specific signal sequences by the presence and absence, respectively, of multiple-arginine and hydrophobic sequence motifs in the N-terminal region.
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Affiliation(s)
- Dong Wook Lee
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sumin Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Junho Lee
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Seungjin Woo
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Md Abdur Razzak
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Alessandro Vitale
- Istituto di Biologia e Biotecnologia Agraria, Consiglio Nazionale Delle Ricerche, Milano, Italy
| | - Inhwan Hwang
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673, Korea; Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673, Korea.
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Sato TK, Kawano S, Endo T. Role of the membrane potential in mitochondrial protein unfolding and import. Sci Rep 2019; 9:7637. [PMID: 31114030 PMCID: PMC6529458 DOI: 10.1038/s41598-019-44152-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 05/10/2019] [Indexed: 12/02/2022] Open
Abstract
Newly synthesized mitochondrial precursor proteins have to become unfolded to cross the mitochondrial membranes. This unfolding is achieved primarily by mitochondrial Hsp70 (mtHsp70) for presequence-containing precursor proteins. However, the membrane potential across the inner membrane (ΔΨ) could also contribute to unfolding of short-presequence containing mitochondrial precursor proteins. Here we investigated the role of ΔΨ in mitochondrial protein unfolding and import. We found that the effects of mutations in the presequence on import rates are correlated well with the hydrophobicity or ability to interact with import motor components including mtHsp70, but not with ΔΨ (negative inside). A spontaneously unfolded precursor protein with a short presequence is therefore trapped by motor components including mtHsp70, but not ΔΨ, which could cause global unfolding of the precursor protein. Instead, ΔΨ may contribute the precursor unfolding by holding the presequence at the inner membrane for trapping of the unfolded species by the import motor system.
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Affiliation(s)
- Takehiro K Sato
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.,Spiber Inc. 234-1 Mizukami, Kakuganji, Tsuruoka, Yamagata, 997-0052, Japan
| | - Shin Kawano
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan.,Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Toshiya Endo
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan. .,Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan. .,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
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43
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Mitochondrial presequence import: Multiple regulatory knobs fine-tune mitochondrial biogenesis and homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:930-944. [PMID: 30802482 DOI: 10.1016/j.bbamcr.2019.02.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/22/2022]
Abstract
Mitochondria are pivotal organelles for cellular signaling and metabolism, and their dysfunction leads to severe cellular stress. About 60-70% of the mitochondrial proteome consists of preproteins synthesized in the cytosol with an amino-terminal cleavable presequence targeting signal. The TIM23 complex transports presequence signals towards the mitochondrial matrix. Ultimately, the mature protein segments are either transported into the matrix or sorted to the inner membrane. To ensure accurate preprotein import into distinct mitochondrial sub-compartments, the TIM23 machinery adopts specific functional conformations and interacts with different partner complexes. Regulatory subunits modulate the translocase dynamics, tailoring the import reaction to the incoming preprotein. The mitochondrial membrane potential and the ATP generated via oxidative phosphorylation are key energy sources in driving the presequence import pathway. Thus, mitochondrial dysfunctions have rapid repercussions on biogenesis. Cellular mechanisms exploit the presequence import pathway to monitor mitochondrial dysfunctions and mount transcriptional and proteostatic responses to restore functionality.
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44
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Ueda E, Tamura Y, Sakaue H, Kawano S, Kakuta C, Matsumoto S, Endo T. Myristoyl group-aided protein import into the mitochondrial intermembrane space. Sci Rep 2019; 9:1185. [PMID: 30718713 PMCID: PMC6362269 DOI: 10.1038/s41598-018-38016-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
The MICOS complex mediates formation of the crista junctions in mitochondria. Here we analyzed the mitochondrial import pathways for the six yeast MICOS subunits as a step toward understanding of the assembly mechanisms of the MICOS complex. Mic10, Mic12, Mic26, Mic27, and Mic60 used the presequence pathway to reach the intermembrane space (IMS). In contrast, Mic19 took the TIM40/MIA pathway, through its CHCH domain, to reach the IMS. Unlike canonical TIM40/MIA substrates, presence of the N-terminal unfolded DUF domain impaired the import efficiency of Mic19, yet N-terminal myristoylation of Mic19 circumvented this effect. The myristoyl group of Mic19 binds to Tom20 of the TOM complex as well as the outer membrane, which may lead to "entropy pushing" of the DUF domain followed by the CHCH domain of Mic19 into the import channel, thereby achieving efficient import.
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Affiliation(s)
- Eri Ueda
- Department of Chemistry, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya, 464-8602, Japan
- Department of Biological Science, Graduate School of Science, Osaka University, 1-1 machikaneyama-cho, Toyonaka, 560-0043, Osaka, Japan
| | - Yasushi Tamura
- Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, 990-8560, Japan
| | - Haruka Sakaue
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Shin Kawano
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Chika Kakuta
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Shunsuke Matsumoto
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
- Research Center for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto, 603-8555, Japan.
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45
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Heinemeyer T, Stemmet M, Bardien S, Neethling A. Underappreciated Roles of the Translocase of the Outer and Inner Mitochondrial Membrane Protein Complexes in Human Disease. DNA Cell Biol 2018; 38:23-40. [PMID: 30481057 DOI: 10.1089/dna.2018.4292] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are critical for cellular survival, and for their proper functioning, translocation of ∼1500 proteins across the mitochondrial membranes is required. The translocase of the outer (TOMM) and inner mitochondrial membrane (TIMM) complexes are major components of this translocation machinery. Through specific processes, preproteins and other molecules are imported, translocated, and directed to specific mitochondrial compartments for their function. In this study, we review the association of subunits of these complexes with human disease. Pathogenic mutations have been identified in the TIMM8A (DDP) and DNAJC19 (TIMM14) genes and are linked to Mohr-Tranebjærg syndrome and dilated cardiomyopathy syndrome (with and without ataxia), respectively. Polymorphisms in TOMM40 have been associated with Alzheimer's disease, frontotemporal lobar degeneration, Parkinson's disease with dementia, dementia with Lewy bodies, nonpathological cognitive aging, and various cardiovascular-related traits. Furthermore, reduced protein expression levels of several complex subunits have been associated with Parkinson's disease, Meniere's disease, and cardiovascular disorders. However, increased mRNA and protein levels of complex subunits are found in cancers. This review highlights the importance of the mitochondrial import machinery in human disease and stresses the need for further studies. Ultimately, this knowledge may prove to be critical for the development of therapeutic modalities for these conditions.
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Affiliation(s)
- Thea Heinemeyer
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town, South Africa
| | - Monique Stemmet
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town, South Africa
| | - Soraya Bardien
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town, South Africa
| | - Annika Neethling
- Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University , Cape Town, South Africa
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46
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Srivastava A, Tama F, Kohda D, Miyashita O. Computational investigation of the conformational dynamics in Tom20-mitochondrial presequence tethered complexes. Proteins 2018; 87:81-90. [DOI: 10.1002/prot.25625] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 10/03/2018] [Accepted: 10/16/2018] [Indexed: 12/28/2022]
Affiliation(s)
- Arpita Srivastava
- Department of Physics; Graduate School of Science, Nagoya University; Nagoya Japan
| | - Florence Tama
- Department of Physics; Graduate School of Science, Nagoya University; Nagoya Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University; Nagoya Japan
- RIKEN Center for Computational Science; Kobe Japan
| | - Daisuke Kohda
- Division of Structural Biology; Medical Institute of Bioregulation, Kyushu University; Fukuoka Japan
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47
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Hu W, Wang Z, Zheng H. Mitochondrial accumulation of amyloid β (Aβ) peptides requires TOMM22 as a main Aβ receptor in yeast. J Biol Chem 2018; 293:12681-12689. [PMID: 29925587 PMCID: PMC6102147 DOI: 10.1074/jbc.ra118.002713] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/14/2018] [Indexed: 01/26/2023] Open
Abstract
Mitochondrial accumulation of intracellular β-amyloid (Aβ) peptides is present in the brains of individuals with Alzheimer's disease (AD) as well as in related mouse models of AD. This accumulation is extremely toxic because Aβ disrupts the normal functions of many mitochondrial proteins, resulting in significant mitochondrial dysfunction. Therefore, understanding the mitochondrial accumulation of Aβ is useful for future pharmaceutical design of drugs to address mitochondrial dysfunction in AD. However, the detailed molecular mechanism of this accumulation process remains elusive. Here, using yeast mitochondria, we present direct experimental evidence suggesting that Aβ is specifically recognized by translocase of outer mitochondrial membrane subunit 22 (Tom22 in yeast; TOMM22 in human), a noncanonical receptor within the mitochondrial protein import machinery, and that this recognition is critical for Aβ accumulation in mitochondria. Furthermore, we found that residues 25-42 in the Aβ peptide mediate the specific interaction with TOMM22. On the basis of our findings, we propose that cytosolic Aβ is recognized by TOMM22; transferred to another translocase subunit, TOMM40; and transported through the TOMM channel into the mitochondria. Our results not only confirm that yeast mitochondria can be used as a model to study mitochondrial dysfunction caused by Aβ peptides in AD but also pave the way for future studies of the molecular mechanism of mitochondrial Aβ accumulation.
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Affiliation(s)
- Wenxin Hu
- From the Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045
| | - Zhiming Wang
- From the Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045
| | - Hongjin Zheng
- From the Department of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, To whom correspondence should be addressed:
Dept. of Biochemistry and Molecular Genetics, University of Colorado Denver School of Medicine, Mail Stop 8101, Aurora, CO 80045. Tel.:
303-724-9374; Fax:
303-724-3215; E-mail:
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48
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Jores T, Lawatscheck J, Beke V, Franz-Wachtel M, Yunoki K, Fitzgerald JC, Macek B, Endo T, Kalbacher H, Buchner J, Rapaport D. Cytosolic Hsp70 and Hsp40 chaperones enable the biogenesis of mitochondrial β-barrel proteins. J Cell Biol 2018; 217:3091-3108. [PMID: 29930205 PMCID: PMC6122992 DOI: 10.1083/jcb.201712029] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/04/2018] [Accepted: 05/31/2018] [Indexed: 11/22/2022] Open
Abstract
Mitochondrial β-barrel proteins are imported from the cytosol into the organelle. Jores et al. provide new insights into the early events of this process by describing an array of cytosolic chaperones and cochaperones that associate with newly synthesized β-barrel proteins and assure their optimal biogenesis. Mitochondrial β-barrel proteins are encoded in the nucleus, translated by cytosolic ribosomes, and then imported into the organelle. Recently, a detailed understanding of the intramitochondrial import pathway of β-barrel proteins was obtained. In contrast, it is still completely unclear how newly synthesized β-barrel proteins reach the mitochondrial surface in an import-competent conformation. In this study, we show that cytosolic Hsp70 chaperones and their Hsp40 cochaperones Ydj1 and Sis1 interact with newly synthesized β-barrel proteins. These interactions are highly relevant for proper biogenesis, as inhibiting the activity of the cytosolic Hsp70, preventing its docking to the mitochondrial receptor Tom70, or depleting both Ydj1 and Sis1 resulted in a significant reduction in the import of such substrates into mitochondria. Further experiments demonstrate that the interactions between β-barrel proteins and Hsp70 chaperones and their importance are conserved also in mammalian cells. Collectively, this study outlines a novel mechanism in the early events of the biogenesis of mitochondrial outer membrane β-barrel proteins.
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Affiliation(s)
- Tobias Jores
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Jannis Lawatscheck
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Garching, Germany
| | - Viktor Beke
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Mirita Franz-Wachtel
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Kaori Yunoki
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Julia C Fitzgerald
- Department of Neurodegenerative Diseases and Hertie-Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Boris Macek
- Proteome Center Tübingen, Interfaculty Institute for Cell Biology, University of Tübingen, Tübingen, Germany
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Hubert Kalbacher
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science, Department Chemie, Technische Universität München, Garching, Germany
| | - Doron Rapaport
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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49
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"Multiple partial recognitions in dynamic equilibrium" in the binding sites of proteins form the molecular basis of promiscuous recognition of structurally diverse ligands. Biophys Rev 2017; 10:421-433. [PMID: 29243092 DOI: 10.1007/s12551-017-0365-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 11/19/2017] [Indexed: 12/12/2022] Open
Abstract
Promiscuous recognition of ligands by proteins is as important as strict recognition in numerous biological processes. In living cells, many short, linear amino acid motifs function as targeting signals in proteins to specify the final destination of the protein transport. In general, the target signal is defined by a consensus sequence containing wild-characters, and hence represented by diverse amino acid sequences. The classical lock-and-key or induced-fit/conformational selection mechanism may not cover all aspects of the promiscuous recognition. On the basis of our crystallographic and NMR studies on the mitochondrial Tom20 protein-presequence interaction, we proposed a new hypothetical mechanism based on "a rapid equilibrium of multiple states with partial recognitions". This dynamic, multiple recognition mode enables the Tom20 receptor to recognize diverse mitochondrial presequences with nearly equal affinities. The plant Tom20 is evolutionally unrelated to the animal Tom20 in our study, but is a functional homolog of the animal/fungal Tom20. NMR studies by another research group revealed that the presequence binding by the plant Tom20 was not fully explained by simple interaction modes, suggesting the presence of a similar dynamic, multiple recognition mode. Circumstantial evidence also suggested that similar dynamic mechanisms may be applicable to other promiscuous recognitions of signal peptides by the SRP54/Ffh and SecA proteins.
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Fukasawa Y, Oda T, Tomii K, Imai K. Origin and Evolutionary Alteration of the Mitochondrial Import System in Eukaryotic Lineages. Mol Biol Evol 2017; 34:1574-1586. [PMID: 28369657 PMCID: PMC5455965 DOI: 10.1093/molbev/msx096] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Protein transport systems are fundamentally important for maintaining mitochondrial function. Nevertheless, mitochondrial protein translocases such as the kinetoplastid ATOM complex have recently been shown to vary in eukaryotic lineages. Various evolutionary hypotheses have been formulated to explain this diversity. To resolve any contradiction, estimating the primitive state and clarifying changes from that state are necessary. Here, we present more likely primitive models of mitochondrial translocases, specifically the translocase of the outer membrane (TOM) and translocase of the inner membrane (TIM) complexes, using scrutinized phylogenetic profiles. We then analyzed the translocases’ evolution in eukaryotic lineages. Based on those results, we propose a novel evolutionary scenario for diversification of the mitochondrial transport system. Our results indicate that presequence transport machinery was mostly established in the last eukaryotic common ancestor, and that primitive translocases already had a pathway for transporting presequence-containing proteins. Moreover, secondary changes including convergent and migrational gains of a presequence receptor in TOM and TIM complexes, respectively, likely resulted from constrained evolution. The nature of a targeting signal can constrain alteration to the protein transport complex.
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Affiliation(s)
- Yoshinori Fukasawa
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Toshiyuki Oda
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Kentaro Tomii
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
| | - Kenichiro Imai
- Artificial Intelligence Research Center, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan.,Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Science and Technology (AIST), Tokyo, Japan
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