1
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Koch C, Lenhard S, Räschle M, Prescianotto-Baschong C, Spang A, Herrmann JM. The ER-SURF pathway uses ER-mitochondria contact sites for protein targeting to mitochondria. EMBO Rep 2024; 25:2071-2096. [PMID: 38565738 PMCID: PMC11014988 DOI: 10.1038/s44319-024-00113-w] [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: 08/31/2023] [Revised: 02/14/2024] [Accepted: 02/20/2024] [Indexed: 04/04/2024] Open
Abstract
Most mitochondrial proteins are synthesized on cytosolic ribosomes and imported into mitochondria in a post-translational reaction. Mitochondrial precursor proteins which use the ER-SURF pathway employ the surface of the endoplasmic reticulum (ER) as an important sorting platform. How they reach the mitochondrial import machinery from the ER is not known. Here we show that mitochondrial contact sites play a crucial role in the ER-to-mitochondria transfer of precursor proteins. The ER mitochondria encounter structure (ERMES) and Tom70, together with Djp1 and Lam6, are part of two parallel and partially redundant ER-to-mitochondria delivery routes. When ER-to-mitochondria transfer is prevented by loss of these two contact sites, many precursors of mitochondrial inner membrane proteins are left stranded on the ER membrane, resulting in mitochondrial dysfunction. Our observations support an active role of the ER in mitochondrial protein biogenesis.
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Affiliation(s)
- Christian Koch
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Svenja Lenhard
- Cell Biology, University of Kaiserslautern, Kaiserslautern, Germany
| | - Markus Räschle
- Molecular Genetics, University of Kaiserslautern, Kaiserslautern, Germany
| | | | - Anne Spang
- Biozentrum, University of Basel, 4056, Basel, Switzerland
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2
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Shiino H, Tashiro S, Hashimoto M, Sakata Y, Hosoya T, Endo T, Kojima H, Tamura Y. Chemical inhibition of phosphatidylcholine biogenesis reveals its role in mitochondrial division. iScience 2024; 27:109189. [PMID: 38420588 PMCID: PMC10901091 DOI: 10.1016/j.isci.2024.109189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/19/2023] [Accepted: 02/06/2024] [Indexed: 03/02/2024] Open
Abstract
Phospholipids are major components of biological membranes and play structural and regulatory roles in various biological processes. To determine the biological significance of phospholipids, the use of chemical inhibitors of phospholipid metabolism offers an effective approach; however, the availability of such compounds is limited. In this study, we performed a chemical-genetic screening using yeast and identified small molecules capable of inhibiting phosphatidylcholine (PC) biogenesis, which we designated PC inhibitors 1, 2, 3, and 4 (PCiB-1, 2, 3, and 4). Biochemical analyses indicated that PCiB-2, 3, and 4 inhibited the phosphatidylethanolamine (PE) methyltransferase activity of Cho2, whereas PCiB-1 may inhibit PE transport from mitochondria to the endoplasmic reticulum (ER). Interestingly, we found that PCiB treatment resulted in mitochondrial fragmentation, which was suppressed by expression of a dominant-negative mutant of the mitochondrial division factor Dnm1. These results provide evidence that normal PC biogenesis is important for the regulation of mitochondrial division.
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Affiliation(s)
- Hiroya Shiino
- Graduate School of Global Symbiotic Sciences, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan
| | - Shinya Tashiro
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Michiko Hashimoto
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Yuki Sakata
- Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Takamitsu Hosoya
- Laboratory of Chemical Bioscience, Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kamigamo-motoyama, Kyoto 603-8555, Japan
- Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kyoto 603-8555, Japan
| | - Hirotatsu Kojima
- Drug Discovery Initiative, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yasushi Tamura
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
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3
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Kučerová J, Zdrha A, Shinde A, Harant K, Hrdý I, Tachezy J. The divergent ER-mitochondria encounter structures (ERMES) are conserved in parabasalids but lost in several anaerobic lineages with hydrogenosomes. BMC Biol 2023; 21:259. [PMID: 37968591 PMCID: PMC10648710 DOI: 10.1186/s12915-023-01765-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 11/09/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND The endoplasmic reticulum (ER)-mitochondria membrane contact sites (MCS) are extensively studied in aerobic eukaryotes; however, little is known about MCS in anaerobes with reduced forms of mitochondria named hydrogenosomes. In several eukaryotic lineages, the direct physical tether between ER and the outer mitochondrial membrane is formed by ER-mitochondria encounter structure (ERMES). The complex consists of four core proteins (Mmm1, Mmm2, Mdm12, and Mdm10) which are involved in phospholipid trafficking. Here we investigated ERMES distribution in organisms bearing hydrogenosomes and employed Trichomonas vaginalis as a model to estimate ERMES cellular localization, structure, and function. RESULTS Homology searches revealed that Parabasalia-Anaeramoebae, anaerobic jakobids, and anaerobic fungi are lineages with hydrogenosomes that retain ERMES, while ERMES components were gradually lost in Fornicata, and are absent in Preaxostyla and Archamoebae. In T. vaginalis and other parabasalids, three ERMES components were found with the expansion of Mmm1. Immunofluorescence microscopy confirmed that Mmm1 localized in ER, while Mdm12 and Mmm2 were partially localized in hydrogenosomes. Pull-down assays and mass spectrometry of the ERMES components identified a parabasalid-specific Porin2 as a substitute for the Mdm10. ERMES modeling predicted a formation of a continuous hydrophobic tunnel of TvMmm1-TvMdm12-TvMmm2 that is anchored via Porin2 to the hydrogenosomal outer membrane. Phospholipid-ERMES docking and Mdm12-phospholipid dot-blot indicated that ERMES is involved in the transport of phosphatidylinositol phosphates. The absence of enzymes involved in hydrogenosomal phospholipid metabolism implies that ERMES is not involved in the exchange of substrates between ER and hydrogenosomes but in the unidirectional import of phospholipids into hydrogenosomal membranes. CONCLUSIONS Our investigation demonstrated that ERMES mediates ER-hydrogenosome interactions in parabasalid T. vaginalis, while the complex was lost in several other lineages with hydrogenosomes.
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Affiliation(s)
- Jitka Kučerová
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic
| | - Alois Zdrha
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic
| | - Abhishek Shinde
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic
| | - Karel Harant
- OMICS Proteomics Laboratory, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic
| | - Ivan Hrdý
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic
| | - Jan Tachezy
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV, Průmyslová 595, 25242, Vestec, Czech Republic.
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4
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Khaddaj R, Kukulski W. Piecing together the structural organisation of lipid exchange at membrane contact sites. Curr Opin Cell Biol 2023; 83:102212. [PMID: 37515839 DOI: 10.1016/j.ceb.2023.102212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/29/2023] [Accepted: 06/30/2023] [Indexed: 07/31/2023]
Abstract
Membrane contact sites (MCSs) are areas of close proximity between organelles, implicated in transport of small molecules and in organelle biogenesis. Lipid transfer proteins at MCSs facilitate the distribution of lipid species between organelle membranes. Such exchange processes rely on the apposition of two different membranes delimiting distinct compartments and a cytosolic intermembrane space. Maintaining organelle identity while transferring molecules therefore implies control over MCS architecture both on the ultrastructural and molecular levels. Factors including intermembrane distance, density of resident proteins, and contact surface area fine-tune MCS function. Furthermore, the structural arrangement of lipid transfer proteins and associated proteins underpins the molecular mechanisms of lipid fluxes at MCSs. Thus, the architecture of MCSs emerges as an essential aspect of their function.
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Affiliation(s)
- Rasha Khaddaj
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland
| | - Wanda Kukulski
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, 3012 Bern, Switzerland.
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5
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Wozny MR, Di Luca A, Morado DR, Picco A, Khaddaj R, Campomanes P, Ivanović L, Hoffmann PC, Miller EA, Vanni S, Kukulski W. In situ architecture of the ER-mitochondria encounter structure. Nature 2023:10.1038/s41586-023-06050-3. [PMID: 37165187 DOI: 10.1038/s41586-023-06050-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 04/04/2023] [Indexed: 05/12/2023]
Abstract
The endoplasmic reticulum and mitochondria are main hubs of eukaryotic membrane biogenesis that rely on lipid exchange via membrane contact sites1-3, but the underpinning mechanisms remain poorly understood. In yeast, tethering and lipid transfer between the two organelles is mediated by the endoplasmic reticulum-mitochondria encounter structure (ERMES), a four-subunit complex of unresolved stoichiometry and architecture4-6. Here we determined the molecular organization of ERMES within Saccharomyces cerevisiae cells using integrative structural biology by combining quantitative live imaging, cryo-correlative microscopy, subtomogram averaging and molecular modelling. We found that ERMES assembles into approximately 25 discrete bridge-like complexes distributed irregularly across a contact site. Each bridge consists of three synaptotagmin-like mitochondrial lipid binding protein domains oriented in a zig-zag arrangement. Our molecular model of ERMES reveals a pathway for lipids. These findings resolve the in situ supramolecular architecture of a major inter-organelle lipid transfer machinery and provide a basis for the mechanistic understanding of lipid fluxes in eukaryotic cells.
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Affiliation(s)
- Michael R Wozny
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Andrea Di Luca
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dustin R Morado
- MRC Laboratory of Molecular Biology, Cambridge, UK
- SciLifeLab, Solna, Sweden
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Andrea Picco
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Rasha Khaddaj
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Lazar Ivanović
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Patrick C Hoffmann
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
| | - Wanda Kukulski
- MRC Laboratory of Molecular Biology, Cambridge, UK.
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
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6
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Dall'Armellina F, Stagi M, Swan LE. In silico modeling human VPS13 proteins associated with donor and target membranes suggests lipid transfer mechanisms. Proteins 2023; 91:439-455. [PMID: 36404287 PMCID: PMC10953354 DOI: 10.1002/prot.26446] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/14/2022] [Accepted: 11/03/2022] [Indexed: 11/22/2022]
Abstract
The VPS13 protein family constitutes a novel class of bridge-like lipid transferases. Autosomal recessive inheritance of mutations in VPS13 genes is associated with the development of neurodegenerative diseases in humans. Bioinformatic approaches previously recognized the domain architecture of these proteins. In this study, we model the first ever full-length structures of the four human homologs VPS13A, VPS13B, VPS13C, and VPS13D in association with model membranes, to investigate their lipid transfer ability and potential structural association with membrane leaflets. We analyze the evolutionary conservation and physicochemical properties of these proteins, focusing on conserved C-terminal amphipathic helices that disturb organelle surfaces and that, adjoined, resemble a traditional Venetian gondola. The gondola domains share significant structural homology with lipid droplet surface-binding proteins. We introduce in silico protein-membrane models displaying the mode of association of VPS13A, VPS13B, VPS13C, and VPS13D to donor and target membranes, and present potential models of action for protein-mediated lipid transfer.
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Affiliation(s)
- Filippo Dall'Armellina
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Massimiliano Stagi
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Laura E. Swan
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
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7
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Wang Y, Li Z, Wang X, Zhao Z, Jiao L, Liu R, Wang K, Ma R, Yang Y, Chen G, Wang Y, Bian X. Insights into membrane association of the SMP domain of extended synaptotagmin. Nat Commun 2023; 14:1504. [PMID: 36932127 PMCID: PMC10023780 DOI: 10.1038/s41467-023-37202-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
The Synaptotagmin-like Mitochondrial-lipid-binding Protein (SMP) domain is a newly identified lipid transfer module present in proteins that regulate lipid homeostasis at membrane contact sites (MCSs). However, how the SMP domain associates with the membrane to extract and unload lipids is unclear. Here, we performed in vitro DNA brick-assisted lipid transfer assays and in silico molecular dynamics simulations to investigate the molecular basis of the membrane association by the SMP domain of extended synaptotagmin (E-Syt), which tethers the tubular endoplasmic reticulum (ER) to the plasma membrane (PM). We demonstrate that the SMP domain uses its tip region to recognize the extremely curved subdomain of tubular ER and the acidic-lipid-enriched PM for highly efficient lipid transfer. Supporting these findings, disruption of these mechanisms results in a defect in autophagosome biogenesis contributed by E-Syt. Our results suggest a model that provides a coherent picture of the action of the SMP domain at MCSs.
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Affiliation(s)
- Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Zhenni Li
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Xinyu Wang
- College of Life Sciences, Nankai University, Tianjin, China
| | - Ziyuan Zhao
- College of Life Sciences, Nankai University, Tianjin, China
| | - Li Jiao
- College of Life Sciences, Nankai University, Tianjin, China
| | - Ruming Liu
- College of Life Sciences, Nankai University, Tianjin, China
| | - Keying Wang
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Rui Ma
- College of Physical Science and Technology, Xiamen University, Xiamen, China
| | - Yang Yang
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Guo Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, China.
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, China.
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China.
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8
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Fujimoto S, Tashiro S, Tamura Y. Complementation Assay Using Fusion of Split-GFP and TurboID (CsFiND) Enables Simultaneous Visualization and Proximity Labeling of Organelle Contact Sites in Yeast. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564231153621. [PMID: 37366411 PMCID: PMC10243572 DOI: 10.1177/25152564231153621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Numerous studies have revealed that organelle membrane contact sites (MCSs) play important roles in diverse cellular events, including the transport of lipids and ions between connected organelles. To understand MCS functions, it is essential to uncover proteins that accumulate at MCSs. Here, we develop a complementation assay system termed CsFiND (Complementation assay using Fusion of split-GFP and TurboID) for the simultaneous visualization of MCSs and identification of MCS-localized proteins. We express the CsFiND proteins on the endoplasmic reticulum and mitochondrial outer membrane in yeast to verify the reliability of CsFiND as a tool for identifying MCS-localized proteins.
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Affiliation(s)
| | - Shinya Tashiro
- Faculty of Science, Yamagata University, Yamagata, Japan
| | - Yasushi Tamura
- Faculty of Science, Yamagata University, Yamagata, Japan
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9
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Kakimoto-Takeda Y, Kojima R, Shiino H, Shinmyo M, Kurokawa K, Nakano A, Endo T, Tamura Y. Dissociation of ERMES clusters plays a key role in attenuating the endoplasmic reticulum stress. iScience 2022; 25:105362. [PMID: 36339260 PMCID: PMC9626684 DOI: 10.1016/j.isci.2022.105362] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/24/2022] [Accepted: 10/12/2022] [Indexed: 11/27/2022] Open
Abstract
In yeast, ERMES, which mediates phospholipid transport between the ER and mitochondria, forms a limited number of oligomeric clusters at ER-mitochondria contact sites in a cell. Although the number of the ERMES clusters appears to be regulated to maintain proper inter-organelle phospholipid trafficking, its underlying mechanism and physiological relevance remain poorly understood. Here, we show that mitochondrial dynamics control the number of ERMES clusters. Moreover, we find that ER stress causes dissociation of the ERMES clusters independently of Ire1 and Hac1, canonical ER-stress response pathway components, leading to a delay in the phospholipid transport from the ER to mitochondria. Our biochemical and genetic analyses strongly suggest that the impaired phospholipid transport contributes to phospholipid accumulation in the ER, expanding the ER for ER stress attenuation. We thus propose that the ERMES dissociation constitutes an overlooked pathway of the ER stress response that operates in addition to the canonical Ire1/Hac1-dependent pathway. Mitochondrial fusion and division regulate the clustering of the ERMES complex ER stress leads to dissociation of the ERMES clusters independently of Ire1 and Hac1 The dissociated ERMES complexes have less activity in transporting phospholipids The defective phospholipid transport may cause the ER expansion to relieve ER stress
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Affiliation(s)
- Yuriko Kakimoto-Takeda
- Department of Biochemistry and Molecular Biology, Graduate School of Medical Science, Yamagata University, 2-2-2 Iidanishi, Yamagata 990-9585, Japan
| | - Rieko Kojima
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan
| | - Hiroya Shiino
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan
| | - Manatsu Shinmyo
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Toshiya Endo
- 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
| | - Yasushi Tamura
- Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata 990-8560, Japan
- Corresponding author
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10
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Kim H, Lee S, Jun Y, Lee C. Structural basis for mitoguardin-2 mediated lipid transport at ER-mitochondrial membrane contact sites. Nat Commun 2022; 13:3702. [PMID: 35764626 PMCID: PMC9239997 DOI: 10.1038/s41467-022-31462-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/17/2022] [Indexed: 11/10/2022] Open
Abstract
The endoplasmic reticulum (ER)-mitochondria contact site (ERMCS) is crucial for exchanging biological molecules such as phospholipids and Ca2+ ions between these organelles. Mitoguardin-2 (MIGA2), a mitochondrial outer membrane protein, forms the ERMCS in higher eukaryotic cells. Here, we report the crystal structures of the MIGA2 Lipid Droplet (LD) targeting domain and the ER membrane protein VAPB bound to the phosphorylated FFAT motif of MIGA2. These structures reveal that the MIGA2 LD targeting domain has a large internal hydrophobic pocket that accommodates phospholipids and that two phosphorylations of the FFAT motif are required for tight interaction of MIGA2 with VAPB, which enhances the rate of lipid transport. Further biochemical studies show that MIGA2 transports phospholipids between membranes with a strong preference for binding and trafficking phosphatidylserine (PS). These results provide a structural and molecular basis for understanding how MIGA2 mediates the formation of ERMCS and facilitates lipid trafficking at the ERMCS. The ER-mitochondria contact sites are crucial for exchanging phospholipids. Here, Kim et al. present crystal structures of mitoguardin-2 (MIGA2) which reveal that MIGA2 directly binds phospholipids and transfers them between the ER and mitochondria.
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Affiliation(s)
- Hyunwoo Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea.,Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Seowhang Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea
| | - Youngsoo Jun
- Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea.,School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju, Korea
| | - Changwook Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Korea. .,Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju, Korea.
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11
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Vrijsen S, Vrancx C, Del Vecchio M, Swinnen JV, Agostinis P, Winderickx J, Vangheluwe P, Annaert W. Inter-organellar Communication in Parkinson's and Alzheimer's Disease: Looking Beyond Endoplasmic Reticulum-Mitochondria Contact Sites. Front Neurosci 2022; 16:900338. [PMID: 35801175 PMCID: PMC9253489 DOI: 10.3389/fnins.2022.900338] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Accepted: 05/05/2022] [Indexed: 01/13/2023] Open
Abstract
Neurodegenerative diseases (NDs) are generally considered proteinopathies but whereas this may initiate disease in familial cases, onset in sporadic diseases may originate from a gradually disrupted organellar homeostasis. Herein, endolysosomal abnormalities, mitochondrial dysfunction, endoplasmic reticulum (ER) stress, and altered lipid metabolism are commonly observed in early preclinical stages of major NDs, including Parkinson's disease (PD) and Alzheimer's disease (AD). Among the multitude of underlying defective molecular mechanisms that have been suggested in the past decades, dysregulation of inter-organellar communication through the so-called membrane contact sites (MCSs) is becoming increasingly apparent. Although MCSs exist between almost every other type of subcellular organelle, to date, most focus has been put on defective communication between the ER and mitochondria in NDs, given these compartments are critical in neuronal survival. Contributions of other MCSs, notably those with endolysosomes and lipid droplets are emerging, supported as well by genetic studies, identifying genes functionally involved in lysosomal homeostasis. In this review, we summarize the molecular identity of the organelle interactome in yeast and mammalian cells, and critically evaluate the evidence supporting the contribution of disturbed MCSs to the general disrupted inter-organellar homeostasis in NDs, taking PD and AD as major examples.
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Affiliation(s)
- Stephanie Vrijsen
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, KU Leuven, Leuven, Belgium
| | - Céline Vrancx
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Mara Del Vecchio
- Laboratory of Functional Biology, Department of Biology, KU Leuven, Heverlee, Belgium
| | - Johannes V. Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, Leuven Cancer Institute (LKI), KU Leuven, Leuven, Belgium
- Johannes V. Swinnen
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, VIB-Center for Cancer Research, KU Leuven, Leuven, Belgium
- Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
- Patrizia Agostinis
| | - Joris Winderickx
- Laboratory of Functional Biology, Department of Biology, KU Leuven, Heverlee, Belgium
- Joris Winderickx
| | - Peter Vangheluwe
- Laboratory of Cellular Transport Systems, Department of Cellular and Molecular Medicine, Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, KU Leuven, Leuven, Belgium
- Peter Vangheluwe
| | - Wim Annaert
- Laboratory for Membrane Trafficking, VIB-Center for Brain and Disease Research, KU Leuven, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
- *Correspondence: Wim Annaert
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12
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METALIC reveals interorganelle lipid flux in live cells by enzymatic mass tagging. Nat Cell Biol 2022; 24:996-1004. [PMID: 35654841 PMCID: PMC9203272 DOI: 10.1038/s41556-022-00917-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 04/18/2022] [Indexed: 11/08/2022]
Abstract
The distinct activities of organelles depend on the proper function of their membranes. Coordinated membrane biogenesis of different organelles necessitates lipid transport from their site of synthesis to their destination. Several factors have been proposed to participate in lipid distribution, but despite its basic importance, in vivo evidence linking the absence of putative transport pathways to specific transport defects remains scarce. A reason for this scarcity is the near absence of in vivo lipid trafficking assays. Here we introduce a versatile method named METALIC (Mass tagging-Enabled TrAcking of Lipids In Cells) to track interorganelle lipid flux inside cells. In this strategy, two enzymes, one directed to a 'donor' and the other to an 'acceptor' organelle, add two distinct mass tags to lipids. Mass-spectrometry-based detection of lipids bearing the two mass tags is then used to quantify exchange between the two organelles. By applying this approach, we show that the ERMES and Vps13-Mcp1 complexes have transport activity in vivo, and unravel their relative contributions to endoplasmic reticulum-mitochondria lipid exchange.
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13
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John Peter AT, Schie SNS, Cheung NJ, Michel AH, Peter M, Kornmann B. Rewiring phospholipid biosynthesis reveals resilience to membrane perturbations and uncovers regulators of lipid homeostasis. EMBO J 2022; 41:e109998. [PMID: 35188676 PMCID: PMC8982615 DOI: 10.15252/embj.2021109998] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 12/20/2021] [Accepted: 01/07/2022] [Indexed: 02/01/2023] Open
Abstract
The organelles of eukaryotic cells differ in their membrane lipid composition. This heterogeneity is achieved by the localization of lipid synthesizing and modifying enzymes to specific compartments, as well as by intracellular lipid transport that utilizes vesicular and non‐vesicular routes to ferry lipids from their place of synthesis to their destination. For instance, the major and essential phospholipids, phosphatidylethanolamine (PE) and phosphatidylcholine (PC), can be produced by multiple pathways and, in the case of PE, also at multiple locations. However, the molecular components that underlie lipid homeostasis as well as the routes allowing their distribution remain unclear. Here, we present an approach in which we simplify and rewire yeast phospholipid synthesis by redirecting PE and PC synthesis reactions to distinct subcellular locations using chimeric enzymes fused to specific organelle targeting motifs. In rewired conditions, viability is expected to depend on homeostatic adaptation to the ensuing lipostatic perturbations and on efficient interorganelle lipid transport. We therefore performed genetic screens to identify factors involved in both of these processes. Among the candidates identified, we find genes linked to transcriptional regulation of lipid homeostasis, lipid metabolism, and transport. In particular, we identify a requirement for Csf1—an uncharacterized protein harboring a Chorein‐N lipid transport motif—for survival under certain rewired conditions as well as lipidomic adaptation to cold, implicating Csf1 in interorganelle lipid transport and homeostatic adaptation.
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Affiliation(s)
| | | | - Ngaam J Cheung
- Department of Biochemistry University of Oxford Oxford UK
| | - Agnès H Michel
- Department of Biochemistry University of Oxford Oxford UK
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14
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Egea PF. Mechanisms of Non-Vesicular Exchange of Lipids at Membrane Contact Sites: Of Shuttles, Tunnels and, Funnels. Front Cell Dev Biol 2021; 9:784367. [PMID: 34912813 PMCID: PMC8667587 DOI: 10.3389/fcell.2021.784367] [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: 09/27/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Eukaryotic cells are characterized by their exquisite compartmentalization resulting from a cornucopia of membrane-bound organelles. Each of these compartments hosts a flurry of biochemical reactions and supports biological functions such as genome storage, membrane protein and lipid biosynthesis/degradation and ATP synthesis, all essential to cellular life. Acting as hubs for the transfer of matter and signals between organelles and throughout the cell, membrane contacts sites (MCSs), sites of close apposition between membranes from different organelles, are essential to cellular homeostasis. One of the now well-acknowledged function of MCSs involves the non-vesicular trafficking of lipids; its characterization answered one long-standing question of eukaryotic cell biology revealing how some organelles receive and distribute their membrane lipids in absence of vesicular trafficking. The endoplasmic reticulum (ER) in synergy with the mitochondria, stands as the nexus for the biosynthesis and distribution of phospholipids (PLs) throughout the cell by contacting nearly all other organelle types. MCSs create and maintain lipid fluxes and gradients essential to the functional asymmetry and polarity of biological membranes throughout the cell. Membrane apposition is mediated by proteinaceous tethers some of which function as lipid transfer proteins (LTPs). We summarize here the current state of mechanistic knowledge of some of the major classes of LTPs and tethers based on the available atomic to near-atomic resolution structures of several "model" MCSs from yeast but also in Metazoans; we describe different models of lipid transfer at MCSs and analyze the determinants of their specificity and directionality. Each of these systems illustrate fundamental principles and mechanisms for the non-vesicular exchange of lipids between eukaryotic membrane-bound organelles essential to a wide range of cellular processes such as at PL biosynthesis and distribution, lipid storage, autophagy and organelle biogenesis.
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Affiliation(s)
- Pascal F Egea
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, CA, United States
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15
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Tamura Y, Kawano S, Endo T. Lipid homeostasis in mitochondria. Biol Chem 2021; 401:821-833. [PMID: 32229651 DOI: 10.1515/hsz-2020-0121] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/10/2020] [Indexed: 12/13/2022]
Abstract
Mitochondria are surrounded by the two membranes, the outer and inner membranes, whose lipid compositions are optimized for proper functions and structural organizations of mitochondria. Although a part of mitochondrial lipids including their characteristic lipids, phosphatidylethanolamine and cardiolipin, are synthesized within mitochondria, their precursor lipids and other lipids are transported from other organelles, mainly the ER. Mitochondrially synthesized lipids are re-distributed within mitochondria and to other organelles, as well. Recent studies pointed to the important roles of inter-organelle contact sites in lipid trafficking between different organelle membranes. Identification of Ups/PRELI proteins as lipid transfer proteins shuttling between the mitochondrial outer and inner membranes established a part of the molecular and structural basis of the still elusive intra-mitochondrial lipid trafficking.
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Affiliation(s)
- Yasushi Tamura
- Faculty of Science, Yamagata University, 1-4-12, Kojirakawa-machi, Yamagata, Yamagata 990-8560, Japan
| | - Shin Kawano
- Faculty of Life Sciences, 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.,Institute for Protein Dynamics, Kyoto Sangyo University, Kamigamo-motoyama, Kita-ku, Kyoto 603-8555, Japan
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16
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Cheung NJ, John Peter AT, Kornmann B. Leri: A web-server for identifying protein functional networks from evolutionary couplings. Comput Struct Biotechnol J 2021; 19:3556-3563. [PMID: 34257835 PMCID: PMC8239741 DOI: 10.1016/j.csbj.2021.06.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 05/30/2021] [Accepted: 06/02/2021] [Indexed: 12/12/2022] Open
Abstract
Identify the evolutionary signatures (termed “residue communities”) from protein sequences. The identified residue communities specify the signatures of protein evolution and function sites. Guide the engineering of functional proteins with altered (bio) chemical activities.
Information on the co-evolution of amino acid pairs in a protein can be used for endeavors such as protein engineering, mutation design, and structure prediction. Here we report a method that captures significant determinants of proteins using estimated co-evolution information to identify networks of residues, termed ”residue communities”, relevant to protein function. On the benchmark dataset (67 proteins with both catalytic and allosteric residues), the Pearson’s correlation between the identified residues in the communities at functional sites is 0.53, and it is higher than 0.8 by taking account of conserved residues derived from the method. On the endoplasmic reticulum-mitochondria encounter structure complex, the results indicate three distinguishable residue communities that are relevant to functional roles in the protein family, suggesting that the residue communities could be general evolutionary signatures in proteins. Based on the method, we provide a webserver for the scientific community to explore the signatures in protein families, which establishes a powerful tool to analyze residue-level profiling for the discovery of functional sites and biological pathway identification. This web-server is freely available for non-commercial users at https://kornmann.bioch.ox.ac.uk/leri/services/ecs.html, neither login nor e-mail required.
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Affiliation(s)
- Ngaam J Cheung
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.,Leri Ltd, Oxford, UK
| | | | - Benoit Kornmann
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
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17
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Aoyama-Ishiwatari S, Hirabayashi Y. Endoplasmic Reticulum-Mitochondria Contact Sites-Emerging Intracellular Signaling Hubs. Front Cell Dev Biol 2021; 9:653828. [PMID: 34095118 PMCID: PMC8172986 DOI: 10.3389/fcell.2021.653828] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/06/2021] [Indexed: 01/04/2023] Open
Abstract
It has become apparent that our textbook illustration of singular isolated organelles is obsolete. In reality, organelles form complex cooperative networks involving various types of organelles. Light microscopic and ultrastructural studies have revealed that mitochondria-endoplasmic reticulum (ER) contact sites (MERCSs) are abundant in various tissues and cell types. Indeed, MERCSs have been proposed to play critical roles in various biochemical and signaling functions such as Ca2+ homeostasis, lipid transfer, and regulation of organelle dynamics. While numerous proteins involved in these MERCS-dependent functions have been reported, how they coordinate and cooperate with each other has not yet been elucidated. In this review, we summarize the functions of mammalian proteins that localize at MERCSs and regulate their formation. We also discuss potential roles of the MERCS proteins in regulating multiple organelle contacts.
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Affiliation(s)
| | - Yusuke Hirabayashi
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan
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18
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Yeo HK, Park TH, Kim HY, Jang H, Lee J, Hwang GS, Ryu SE, Park SH, Song HK, Ban HS, Yoon HJ, Lee BI. Phospholipid transfer function of PTPIP51 at mitochondria-associated ER membranes. EMBO Rep 2021; 22:e51323. [PMID: 33938112 DOI: 10.15252/embr.202051323] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 02/24/2021] [Accepted: 03/22/2021] [Indexed: 01/08/2023] Open
Abstract
In eukaryotic cells, mitochondria are closely tethered to the endoplasmic reticulum (ER) at sites called mitochondria-associated ER membranes (MAMs). Ca2+ ion and phospholipid transfer occurs at MAMs to support diverse cellular functions. Unlike those in yeast, the protein complexes involved in phospholipid transfer at MAMs in humans have not been identified. Here, we determine the crystal structure of the tetratricopeptide repeat domain of PTPIP51 (PTPIP51_TPR), a mitochondrial protein that interacts with the ER-anchored VAPB protein at MAMs. The structure of PTPIP51_TPR shows an archetypal TPR fold, and an electron density map corresponding to an unidentified lipid-like molecule probably derived from the protein expression host is found in the structure. We reveal functions of PTPIP51 in phospholipid binding/transfer, particularly of phosphatidic acid, in vitro. Depletion of PTPIP51 in cells reduces the mitochondrial cardiolipin level. Additionally, we confirm that the PTPIP51-VAPB interaction is mediated by the FFAT-like motif of PTPIP51 and the MSP domain of VAPB. Our findings suggest that PTPIP51 is a phospholipid transfer protein with a MAM-tethering function.
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Affiliation(s)
- Hyun Ku Yeo
- Research Institute, National Cancer Center, Goyang-si, Korea
| | - Tae Hyun Park
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Bioengineering, Hanyang University, Seoul, Korea
| | - Hee Yeon Kim
- Research Institute, National Cancer Center, Goyang-si, Korea
| | - Hyonchol Jang
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Cancer Biomedical Science, National Cancer Center Graduate School of Cancer Science and Policy, Goyang-si, Korea
| | - Jueun Lee
- Integrated Metabolomics Research Group, Western Seoul Center, Korea Basic Science Institute, Seoul, Korea
| | - Geum-Sook Hwang
- Integrated Metabolomics Research Group, Western Seoul Center, Korea Basic Science Institute, Seoul, Korea.,Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Korea
| | - Seong Eon Ryu
- Department of Bioengineering, Hanyang University, Seoul, Korea
| | - Si Hoon Park
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Hyun Kyu Song
- Department of Life Sciences, Korea University, Seoul, Korea
| | - Hyun Seung Ban
- Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Hye-Jin Yoon
- Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, Korea
| | - Byung Il Lee
- Research Institute, National Cancer Center, Goyang-si, Korea.,Department of Cancer Biomedical Science, National Cancer Center Graduate School of Cancer Science and Policy, Goyang-si, Korea
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19
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Acoba MG, Senoo N, Claypool SM. Phospholipid ebb and flow makes mitochondria go. J Cell Biol 2021; 219:151918. [PMID: 32614384 PMCID: PMC7401802 DOI: 10.1083/jcb.202003131] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 01/19/2023] Open
Abstract
Mitochondria, so much more than just being energy factories, also have the capacity to synthesize macromolecules including phospholipids, particularly cardiolipin (CL) and phosphatidylethanolamine (PE). Phospholipids are vital constituents of mitochondrial membranes, impacting the plethora of functions performed by this organelle. Hence, the orchestrated movement of phospholipids to and from the mitochondrion is essential for cellular integrity. In this review, we capture recent advances in the field of mitochondrial phospholipid biosynthesis and trafficking, highlighting the significance of interorganellar communication, intramitochondrial contact sites, and lipid transfer proteins in maintaining membrane homeostasis. We then discuss the physiological functions of CL and PE, specifically how they associate with protein complexes in mitochondrial membranes to support bioenergetics and maintain mitochondrial architecture.
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Affiliation(s)
- Michelle Grace Acoba
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nanami Senoo
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Steven M Claypool
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD
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20
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Rasul F, Zheng F, Dong F, He J, Liu L, Liu W, Cheema JY, Wei W, Fu C. Emr1 regulates the number of foci of the endoplasmic reticulum-mitochondria encounter structure complex. Nat Commun 2021; 12:521. [PMID: 33483504 PMCID: PMC7822926 DOI: 10.1038/s41467-020-20866-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 12/16/2020] [Indexed: 11/21/2022] Open
Abstract
The endoplasmic reticulum-mitochondria encounter structure (ERMES) complex creates contact sites between the endoplasmic reticulum and mitochondria, playing crucial roles in interorganelle communication, mitochondrial fission, mtDNA inheritance, lipid transfer, and autophagy. The mechanism regulating the number of ERMES foci within the cell remains unclear. Here, we demonstrate that the mitochondrial membrane protein Emr1 contributes to regulating the number of ERMES foci. We show that the absence of Emr1 significantly decreases the number of ERMES foci. Moreover, we find that Emr1 interacts with the ERMES core component Mdm12 and colocalizes with Mdm12 on mitochondria. Similar to ERMES mutant cells, cells lacking Emr1 display defective mitochondrial morphology and impaired mitochondrial segregation, which can be rescued by an artificial tether capable of linking the endoplasmic reticulum and mitochondria. We further demonstrate that the cytoplasmic region of Emr1 is required for regulating the number of ERMES foci. This work thus reveals a crucial regulatory protein necessary for ERMES functions and provides mechanistic insights into understanding the dynamic regulation of endoplasmic reticulum-mitochondria communication. Interorganelle membrane contact sites between the endoplasmic reticulum and mitochondria can be mediated with the ER-mitochondria encounter structure (ERMES) complex, though precise regulation is unclear. Here, the authors report that the number of ERMES foci is regulated by the previously uncharacterized mitochondrial membrane protein Emr1.
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Affiliation(s)
- Faiz Rasul
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Fan Zheng
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Fenfen Dong
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Jiajia He
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Ling Liu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Wenyue Liu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Javairia Yousuf Cheema
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China
| | - Wenfan Wei
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China.
| | - Chuanhai Fu
- Ministry of Education Key Laboratory for Membrane-less Organelles & Cellular Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027, Hefei, People's Republic of China.
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21
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TSUBOI M, HIRABAYASHI Y. New insights into the regulation of synaptic transmission and plasticity by the endoplasmic reticulum and its membrane contacts. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:559-572. [PMID: 34897182 PMCID: PMC8687855 DOI: 10.2183/pjab.97.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 10/18/2021] [Indexed: 06/14/2023]
Abstract
Mammalian neurons are highly compartmentalized yet very large cells. To provide each compartment with its distinct properties, metabolic homeostasis and molecular composition need to be precisely coordinated in a compartment-specific manner. Despite the importance of the endoplasmic reticulum (ER) as a platform for various biochemical reactions, such as protein synthesis, protein trafficking, and intracellular calcium control, the contribution of the ER to neuronal compartment-specific functions and plasticity remains elusive. Recent advances in the development of live imaging and serial scanning electron microscopy (sSEM) analysis have revealed that the neuronal ER is a highly dynamic organelle with compartment-specific structures. sSEM studies also revealed that the ER forms contacts with other membranes, such as the mitochondria and plasma membrane, although little is known about the functions of these ER-membrane contacts. In this review, we discuss the mechanisms and physiological roles of the ER structure and ER-mitochondria contacts in synaptic transmission and plasticity, thereby highlighting a potential link between organelle ultrastructure and neuronal functions.
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Affiliation(s)
- Masafumi TSUBOI
- Graduate School of Engineering, The University of Tokyo, Tokyo, Japan
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22
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Cheema JY, He J, Wei W, Fu C. The Endoplasmic Reticulum-Mitochondria Encounter Structure and its Regulatory Proteins. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211064491. [PMID: 37366373 PMCID: PMC10243566 DOI: 10.1177/25152564211064491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
In fungi, the endoplasmic reticulum-mitochondria encounter structure (ERMES) is present between the endoplasmic reticulon (ER) and mitochondria to promote the formation of the ER-mitochondria contact sites. Four constitutive components (Mmm1, Mdm12, Mdm34, and Mdm10) assemble to form the ERMES complex while regulator proteins are required for regulating the organization and function of the ERMES complex. Multiple regulator proteins, including Gem1, Lam6, Tom7, and Emr1, of the ERMES complex, have been identified recently. In this review, we discuss the organization of the ERMES complex and the roles of the regulator proteins of the ERMES complex.
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Affiliation(s)
- Javairia Y. Cheema
- Ministry of Education Key Laboratory for Cellular
Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National
Laboratory for Physical Sciences at the Microscale, School of Life Sciences,
Division of Life Sciences and Medicine, University of Science and Technology
of China, Hefei, P.R. China
| | - Jiajia He
- Ministry of Education Key Laboratory for Cellular
Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National
Laboratory for Physical Sciences at the Microscale, School of Life Sciences,
Division of Life Sciences and Medicine, University of Science and Technology
of China, Hefei, P.R. China
| | - Wenfan Wei
- Ministry of Education Key Laboratory for Cellular
Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National
Laboratory for Physical Sciences at the Microscale, School of Life Sciences,
Division of Life Sciences and Medicine, University of Science and Technology
of China, Hefei, P.R. China
| | - Chuanhai Fu
- Ministry of Education Key Laboratory for Cellular
Dynamics, CAS Center for Excellence in Molecular Cell Sciences, Hefei National
Laboratory for Physical Sciences at the Microscale, School of Life Sciences,
Division of Life Sciences and Medicine, University of Science and Technology
of China, Hefei, P.R. China
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23
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Lin S, Meng T, Huang H, Zhuang H, He Z, Yang H, Feng D. Molecular machineries and physiological relevance of ER-mediated membrane contacts. Theranostics 2021; 11:974-995. [PMID: 33391516 PMCID: PMC7738843 DOI: 10.7150/thno.51871] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023] Open
Abstract
Membrane contact sites (MCSs) are defined as regions where two organelles are closely apposed, and most MCSs associated with each other via protein-protein or protein-lipid interactions. A number of key molecular machinery systems participate in mediating substance exchange and signal transduction, both of which are essential processes in terms of cellular physiology and pathophysiology. The endoplasmic reticulum (ER) is the largest reticulum network within the cell and has extensive communication with other cellular organelles, including the plasma membrane (PM), mitochondria, Golgi, endosomes and lipid droplets (LDs). The contacts and reactions between them are largely mediated by various protein tethers and lipids. Ions, lipids and even proteins can be transported between the ER and neighboring organelles or recruited to the contact site to exert their functions. This review focuses on the key molecules involved in the formation of different contact sites as well as their biological functions.
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Affiliation(s)
- Shiyin Lin
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Tian Meng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Haofeng Huang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
| | - Haixia Zhuang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
| | - Zhengjie He
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Huan Yang
- Department of Pulmonary and Critical Care Medicine, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha 410021, China
| | - Du Feng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
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24
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Shiino H, Furuta S, Kojima R, Kimura K, Endo T, Tamura Y. Phosphatidylserine flux into mitochondria unveiled by organelle-targeted Escherichia coli phosphatidylserine synthase PssA. FEBS J 2020; 288:3285-3299. [PMID: 33283454 DOI: 10.1111/febs.15657] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 11/12/2020] [Accepted: 12/04/2020] [Indexed: 11/26/2022]
Abstract
Most phospholipids are synthesised in the endoplasmic reticulum and distributed to other cellular membranes. Although the vesicle transport contributes to the phospholipid distribution among the endomembrane system, exactly how phospholipids are transported to, from and between mitochondrial membranes remains unclear. To gain insights into phospholipid transport routes into mitochondria, we expressed the Escherichia coli phosphatidylserine (PS) synthase PssA in various membrane compartments with distinct membrane topologies in yeast cells lacking a sole PS synthase (Cho1). Interestingly, PssA could complement loss of Cho1 when targeted to the endoplasmic reticulum (ER), peroxisome, or lipid droplet membranes. Synthesised PS could be converted to phosphatidylethanolamine (PE) by Psd1, the mitochondrial PS decarboxylase, suggesting that phospholipids synthesised in the peroxisomes and low doses (LDs) can efficiently reach mitochondria. Furthermore, we found that PssA which has been integrated into the mitochondrial inner membrane (MIM) from the matrix side could partially complement the loss of Cho1. The PS synthesised in the MIM was also converted to PE, indicating that PS flops across the MIM to become PE. These findings expand our understanding of the intracellular phospholipid transport routes via mitochondria.
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Affiliation(s)
| | | | | | | | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Japan
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25
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English AM, Schuler MH, Xiao T, Kornmann B, Shaw JM, Hughes AL. ER-mitochondria contacts promote mitochondrial-derived compartment biogenesis. J Biophys Biochem Cytol 2020; 219:211482. [PMID: 33090183 PMCID: PMC7588143 DOI: 10.1083/jcb.202002144] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/25/2020] [Accepted: 10/01/2020] [Indexed: 01/04/2023] Open
Abstract
Mitochondria are dynamic organelles with essential roles in signaling and metabolism. We recently identified a cellular structure called the mitochondrial-derived compartment (MDC) that is generated from mitochondria in response to amino acid overabundance stress. How cells form MDCs is unclear. Here, we show that MDCs are dynamic structures that form and stably persist at sites of contact between the ER and mitochondria. MDC biogenesis requires the ER-mitochondria encounter structure (ERMES) and the conserved GTPase Gem1, factors previously implicated in lipid exchange and membrane tethering at ER-mitochondria contacts. Interestingly, common genetic suppressors of abnormalities displayed by ERMES mutants exhibit distinct abilities to rescue MDC formation in ERMES-depleted strains and are incapable of rescuing MDC formation in cells lacking Gem1. Thus, the function of ERMES and Gem1 in MDC biogenesis may extend beyond their conventional role in maintaining mitochondrial phospholipid homeostasis. Overall, this study identifies an important function for ER-mitochondria contacts in the biogenesis of MDCs.
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Affiliation(s)
- Alyssa M. English
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Max-Hinderk Schuler
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Tianyao Xiao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Benoît Kornmann
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Janet M. Shaw
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT
| | - Adam L. Hughes
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT,Correspondence to Adam L. Hughes:
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26
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Liao Y, Dong Y, Cheng J. The Molecular Determinants of Mitochondrial Membrane Contact With ER, Lysosomes and Peroxisomes in Neuronal Physiology and Pathology. Front Cell Neurosci 2020; 14:194. [PMID: 32848610 PMCID: PMC7427582 DOI: 10.3389/fncel.2020.00194] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 06/05/2020] [Indexed: 11/24/2022] Open
Abstract
Membrane tethering is an important communication method for membrane-packaged organelles. Mitochondria are organelles with a bilayer membrane, and the membrane contact between mitochondria and other organelles is indispensable for maintaining cellular homeostasis. Increased levels of molecular determinants that mediate the membrane contact between mitochondria and other organelles, and their functions, have been revealed in recent years. In this review article, we aim to summarize the findings on the tethering between mitochondria and other organelles in physiological or pathological conditions, and discuss their roles in cellular homeostasis, neural activity, and neurodegenerative diseases.
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Affiliation(s)
- Yajin Liao
- Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
| | - Yuan Dong
- Department of Biochemistry, Medical College, Qingdao University, Qingdao, China
| | - Jinbo Cheng
- Center on Translational Neuroscience, College of Life & Environmental Science, Minzu University of China, Beijing, China
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27
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Kornmann B. The endoplasmic reticulum-mitochondria encounter structure: coordinating lipid metabolism across membranes. Biol Chem 2020; 401:811-820. [DOI: 10.1515/hsz-2020-0102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 02/05/2020] [Indexed: 02/06/2023]
Abstract
AbstractEndosymbiosis, the beginning of a collaboration between an archaeon and a bacterium and a founding step in the evolution of eukaryotes, owes its success to the establishment of communication routes between the host and the symbiont to allow the exchange of metabolites. As far as lipids are concerned, it is the host that has learnt the symbiont’s language, as eukaryote lipids appear to have been borrowed from the bacterial symbiont. Mitochondria exchange lipids with the rest of the cell at membrane contact sites. In fungi, the endoplasmic reticulum-mitochondria encounter structure (ERMES) is one of the best understood membrane tethering complexes. Its discovery has yielded crucial insight into the mechanisms of intracellular lipid trafficking. Despite a wealth of data, our understanding of ERMES formation and its exact role(s) remains incomplete. Here, I endeavour to summarise our knowledge on the ERMES complex and to identify lingering gaps.
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Affiliation(s)
- Benoît Kornmann
- Department of Biochemistry, University of Oxford, South Parks Rd, Oxford OX1 3QU, UK
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28
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Kundu D, Pasrija R. The ERMES (Endoplasmic Reticulum and Mitochondria Encounter Structures) mediated functions in fungi. Mitochondrion 2020; 52:89-99. [PMID: 32105794 DOI: 10.1016/j.mito.2020.02.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 12/21/2019] [Accepted: 02/21/2020] [Indexed: 01/01/2023]
Abstract
Cellular organelles are membrane-bound and provide a microenvironment for specific functions. A mitochondrion is a double membranous and dynamic organelle that undergoes numerous fusion/fission events, which depends on various cellular factors. However, it is still dependent on other organelles and requires both communications as well as the movement of physical metabolites between them. Mitochondria interact with different organelles counting lipid droplets (LD), peroxisomes, vacuoles, endoplasmic reticulum (ER) and plasma membrane (PM), etc. Apart from them, mitochondria maintain multiple interactions with ER including ERMES (Endoplasmic Reticulum and Mitochondria encounter structures). ERMES is actually a multi-protein complex, and imperative in the maintenance of mitochondrial morphology and its functions. Its disruption also compromises phospholipid exchange, drug resistance and pathogenicity. This assembly is reportedly unique to fungal systems and proposed as a target for development of new antifungal. In the light of separate reports across diverse fungal systems, we have summarised the information about its distribution and effect on mitochondrial fitness.
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Affiliation(s)
- Deepika Kundu
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana, India
| | - Ritu Pasrija
- Department of Biochemistry, Maharshi Dayanand University, Rohtak, Haryana, India.
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29
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Iadarola DM, Basu Ball W, Trivedi PP, Fu G, Nan B, Gohil VM. Vps39 is required for ethanolamine-stimulated elevation in mitochondrial phosphatidylethanolamine. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158655. [PMID: 32058032 DOI: 10.1016/j.bbalip.2020.158655] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 01/03/2020] [Accepted: 02/04/2020] [Indexed: 12/31/2022]
Abstract
Mitochondrial membrane biogenesis requires the import of phospholipids; however, the molecular mechanisms underlying this process remain elusive. Recent work has implicated membrane contact sites between the mitochondria, endoplasmic reticulum (ER), and vacuole in phospholipid transport. Utilizing a genetic approach focused on these membrane contact site proteins, we have discovered a 'moonlighting' role of the membrane contact site and vesicular fusion protein, Vps39, in phosphatidylethanolamine (PE) transport to the mitochondria. We show that the deletion of Vps39 prevents ethanolamine-stimulated elevation of mitochondrial PE levels without affecting PE biosynthesis in the ER or its transport to other sub-cellular organelles. The loss of Vps39 did not alter the levels of other mitochondrial phospholipids that are biosynthesized ex situ, implying a PE-specific role of Vps39. The abundance of Vps39 and its recruitment to the mitochondria and the ER is dependent on PE levels in each of these organelles, directly implicating Vps39 in the PE transport process. Deletion of essential subunits of Vps39-containing complexes, vCLAMP and HOPS, did not abrogate ethanolamine-stimulated PE elevation in the mitochondria, suggesting an independent role of Vps39 in intracellular PE trafficking. Our work thus identifies Vps39 as a novel player in ethanolamine-stimulated PE transport to the mitochondria.
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Affiliation(s)
- Donna M Iadarola
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Writoban Basu Ball
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Prachi P Trivedi
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Guo Fu
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Beiyan Nan
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA.
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30
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SMP domain proteins in membrane lipid dynamics. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158447. [DOI: 10.1016/j.bbalip.2019.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 12/20/2018] [Accepted: 01/06/2019] [Indexed: 11/24/2022]
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31
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Levine TP. Remote homology searches identify bacterial homologues of eukaryotic lipid transfer proteins, including Chorein-N domains in TamB and AsmA and Mdm31p. BMC Mol Cell Biol 2019; 20:43. [PMID: 31607262 PMCID: PMC6791001 DOI: 10.1186/s12860-019-0226-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/05/2019] [Indexed: 02/07/2023] Open
Abstract
Background All cells rely on lipids for key functions. Lipid transfer proteins allow lipids to exit the hydrophobic environment of bilayers, and cross aqueous spaces. One lipid transfer domain fold present in almost all eukaryotes is the TUbular LIPid binding (TULIP) domain. Three TULIP families have been identified in bacteria (P47, OrfX2 and YceB), but their homology to eukaryotic proteins is too low to specify a common origin. Another recently described eukaryotic lipid transfer domain in VPS13 and ATG2 is Chorein-N, which has no known bacterial homologues. There has been no systematic search for bacterial TULIPs or Chorein-N domains. Results Remote homology predictions for bacterial TULIP domains using HHsearch identified four new TULIP domains in three bacterial families. DUF4403 is a full length pseudo-dimeric TULIP with a 6 strand β-meander dimer interface like eukaryotic TULIPs. A similar sheet is also present in YceB, suggesting it homo-dimerizes. TULIP domains were also found in DUF2140 and in the C-terminus DUF2993. Remote homology predictions for bacterial Chorein-N domains identified strong hits in the N-termini of AsmA and TamB in diderm bacteria, which are related to Mdm31p in eukaryotic mitochondria. The N-terminus of DUF2993 has a Chorein-N domain adjacent to its TULIP domain. Conclusions TULIP lipid transfer domains are widespread in bacteria. Chorein-N domains are also found in bacteria, at the N-terminus of multiple proteins in the intermembrane space of diderms (AsmA, TamB and their relatives) and in Mdm31p, a protein that is likely to have evolved from an AsmA/TamB-like protein in the endosymbiotic mitochondrial ancestor. This indicates that both TULIP and Chorein-N lipid transfer domains may have originated in bacteria.
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Affiliation(s)
- Timothy P Levine
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK.
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32
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Park J, Kim HI, Jeong H, Lee M, Jang SH, Yoon SY, Kim H, Park ZY, Jun Y, Lee C. Quaternary structures of Vac8 differentially regulate the Cvt and PMN pathways. Autophagy 2019; 16:991-1006. [PMID: 31512555 PMCID: PMC7469494 DOI: 10.1080/15548627.2019.1659615] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Armadillo (ARM) repeat proteins constitute a large protein family with diverse and fundamental functions in all organisms, and armadillo repeat domains share high structural similarity. However, exactly how these structurally similar proteins can mediate diverse functions remains a long-standing question. Vac8 (vacuole related 8) is a multifunctional protein that plays pivotal roles in various autophagic pathways, including piecemeal microautophagy of the nucleus (PMN) and cytoplasm-to-vacuole targeting (Cvt) pathways in the budding yeast Saccharomyces cerevisiae. Vac8 comprises an H1 helix at the N terminus, followed by 12 armadillo repeats. Herein, we report the crystal structure of Vac8 bound to Atg13, a key component of autophagic machinery. The 70-Å extended loop of Atg13 binds to the ARM domain of Vac8 in an antiparallel manner. Structural, biochemical, and in vivo experiments demonstrated that the H1 helix of Vac8 intramolecularly associates with the first ARM and regulates its self-association, which is crucial for Cvt and PMN pathways. The structure of H1 helix-deleted Vac8 complexed with Atg13 reveals that Vac8[Δ19–33]-Atg13 forms a heterotetramer and adopts an extended superhelical structure exclusively employed in the Cvt pathway. Most importantly, comparison of Vac8-Nvj1 and Vac8-Atg13 provides a molecular understanding of how a single ARM domain protein adopts different quaternary structures depending on its associated proteins to differentially regulate 2 closely related but distinct cellular pathways. Abbreviations Ape1: aminopeptidase I; ARM: armadillo repeat; Atg: autophagy-related; AUC: analytical ultracentrifugation; Cvt: cytoplasm-to-vacuole targeting; DIC: differential interference contrast; GFP: green fluorescent protein; GST: glutathione-S-transferase; ITC: isothermal titration calorimetry; NVJ: nucleus-vacuole junction; PDB: protein data bank; PMN: piecemeal microautophagy of the nucleus; prApe1: precursor Ape1; RMSD: root-mean-square deviation; SAXS: small-angle X-ray scattering; SD-N: nitrogen starvation medium; SEC: size-exclusion chromatography; tAtg13: Atg13 construct comprising residues 567–695; tNvj1: Nvj1 construct comprising residues 229–321; tVac8: Vac8 construct comprising residues 10–515; Vac8: vacuole related 8
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Affiliation(s)
- Jumi Park
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology , Ulsan, Republic of Korea.,Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Hye-In Kim
- Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea.,School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Hanbin Jeong
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology , Ulsan, Republic of Korea.,Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Miriam Lee
- Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea.,School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Se Hwan Jang
- School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - So Young Yoon
- Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea.,School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Hyejin Kim
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology , Ulsan, Republic of Korea.,Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Zee-Yong Park
- School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Youngsoo Jun
- Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea.,School of Life Sciences, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
| | - Changwook Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Science and Technology , Ulsan, Republic of Korea.,Cell Logistics Research Center, Gwangju Institute of Science and Technology , Gwangju, Republic of Korea
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33
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Nishimura T, Stefan CJ. Specialized ER membrane domains for lipid metabolism and transport. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158492. [PMID: 31349025 DOI: 10.1016/j.bbalip.2019.07.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/15/2022]
Abstract
The endoplasmic reticulum (ER) is a highly organized organelle that performs vital functions including de novo membrane lipid synthesis and transport. Accordingly, numerous lipid biosynthesis enzymes are localized in the ER membrane. However, it is now evident that lipid metabolism is sub-compartmentalized within the ER and that lipid biosynthetic enzymes engage with lipid transfer proteins (LTPs) to rapidly shuttle newly synthesized lipids from the ER to other organelles. As such, intimate relationships between lipid metabolism and lipid transfer pathways exist within the ER network. Notably, certain LTPs enhance the activities of lipid metabolizing enzymes; likewise, lipid metabolism can ensure the specificity of LTP transfer/exchange reactions. Yet, our understanding of these mutual relationships is still emerging. Here, we highlight past and recent key findings on specialized ER membrane domains involved in efficient lipid metabolism and transport and consider unresolved issues in the field.
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Affiliation(s)
- Taki Nishimura
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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34
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Atg2 mediates direct lipid transfer between membranes for autophagosome formation. Nat Struct Mol Biol 2019; 26:281-288. [PMID: 30911189 DOI: 10.1038/s41594-019-0203-4] [Citation(s) in RCA: 284] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 02/15/2019] [Indexed: 12/30/2022]
Abstract
A key event in autophagy is autophagosome formation, whereby the newly synthesized isolation membrane (IM) expands to form a complete autophagosome using endomembrane-derived lipids. Atg2 physically links the edge of the expanding IM with the endoplasmic reticulum (ER), a role that is essential for autophagosome formation. However, the molecular function of Atg2 during ER-IM contact remains unclear, as does the mechanism of lipid delivery to the IM. Here we show that the conserved amino-terminal region of Schizosaccharomyces pombe Atg2 includes a lipid-transfer-protein-like hydrophobic cavity that accommodates phospholipid acyl chains. Atg2 bridges highly curved liposomes, thereby facilitating efficient phospholipid transfer in vitro, a function that is inhibited by mutations that impair autophagosome formation in vivo. These results suggest that Atg2 acts as a lipid-transfer protein that supplies phospholipids for autophagosome formation.
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35
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AhYoung AP, Egea PF. Determining the Lipid-Binding Specificity of SMP Domains: An ERMES Subunit as a Case Study. Methods Mol Biol 2019; 1949:213-235. [PMID: 30790259 DOI: 10.1007/978-1-4939-9136-5_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Membrane contact sites between the endoplasmic reticulum (ER) and mitochondria function as a central hub for the exchange of phospholipids and calcium. The yeast Endoplasmic Reticulum-Mitochondrion Encounter Structure (ERMES) complex is composed of five subunits that tether the ER and mitochondria. Three ERMES subunits (i.e., Mdm12, Mmm1, and Mdm34) contain the synaptotagmin-like mitochondrial lipid-binding protein (SMP) domain. The SMP domain belongs to the tubular lipid-binding protein (TULIP) superfamily, which consists of ubiquitous lipid scavenging and transfer proteins. Herein, we describe the methods for expression and purification of recombinant Mdm12, a bona fide SMP-containing protein, together with the subsequent identification of its bound phospholipids by high-performance thin-layer chromatography (HPTLC) and the characterization of its lipid exchange and transfer functions using lipid displacement and liposome flotation in vitro assays with liposomes as model biological membranes. These methods can be applied to the study and characterization of novel lipid-binding and lipid-transfer proteins.
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Affiliation(s)
- Andrew P AhYoung
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
- Department of Early Discovery Biochemistry, Genentech Inc., South San Francisco, CA, USA
| | - Pascal F Egea
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.
- The Molecular Biology Institute, University of California, Los Angeles, CA, USA.
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36
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Lipid exchange at ER-mitochondria contact sites: a puzzle falling into place with quite a few pieces missing. Curr Opin Cell Biol 2018; 57:71-76. [PMID: 30554079 DOI: 10.1016/j.ceb.2018.11.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 11/20/2018] [Accepted: 11/21/2018] [Indexed: 12/31/2022]
Abstract
Over the last years, the importance of inter-organelle communication has become more and more evident, attested by the fast growing number of newly-identified membrane contact sites (MCS). At MCSs two organelles are connected via protein tethers that bring them in close proximity to facilitate metabolite exchange. In this review, we will focus on the MCSs connecting the ER and mitochondria, which have been implicated in phospholipid transport. While we already know the molecular identity of some tethers, we are still far from understanding the mechanisms underlying the phospholipid transport processes. In vitro studies suggest that some proteins in MCSs are capable of transporting lipids, however only at rates that do not meet the mitochondrial lipid demand. In vivo studies are even more puzzling as it appears that many redundant lipid transport routes, involving various lipid transport proteins and various MCSs, compensate for each other when necessary. Here, we will discuss the challenges in interpreting the data on lipid transport between ER and mitochondria from in vitro and in vivo experiments by highlighting some critical aspects that might be worth addressing in the future.
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37
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Martins VM, Fernandes TR, Lopes D, Afonso CB, Domingues MRM, Côrte-Real M, Sousa MJ. Contacts in Death: The Role of the ER-Mitochondria Axis in Acetic Acid-Induced Apoptosis in Yeast. J Mol Biol 2018; 431:273-288. [PMID: 30414966 DOI: 10.1016/j.jmb.2018.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/12/2018] [Accepted: 11/05/2018] [Indexed: 02/08/2023]
Abstract
Endoplasmic reticulum-mitochondria contact sites have been a subject of increasing scientific interest since the discovery that these structures are disrupted in several pathologies. Due to the emerging data that correlate endoplasmic reticulum-mitochondria contact sites function with known events of the apoptotic program, we aimed to dissect this interplay using our well-established model of acetic acid-induced apoptosis in Saccharomyces cerevisiae. Until recently, the only known tethering complex between ER and mitochondria in this organism was the ER-mitochondria encounter structure (ERMES). Following our results from a screening designed to identify genes whose deletion rendered cells with an altered sensitivity to acetic acid, we hypothesized that the ERMES complex could be involved in cell death mediated by this stressor. Herein we demonstrate that single ablation of the ERMES components Mdm10p, Mdm12p and Mdm34p increases the resistance of S. cerevisiae to acetic acid-induced apoptosis, which is associated with a prominent delay in the appearance of several apoptotic markers. Moreover, abrogation of Mdm10p or Mdm34p abolished cytochrome c release from mitochondria. Since these two proteins are embedded in the mitochondrial outer membrane, we propose that the ERMES complex plays a part in cytochrome c release, a key event of the apoptotic cascade. In all, these findings will aid in targeted therapies for diseases where apoptosis is disrupted, as well as assist in the development of acetic acid-resistant strains for industrial processes.
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Affiliation(s)
- Vítor M Martins
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
| | - Tânia R Fernandes
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Diana Lopes
- Mass Spectrometry Centre, Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Department of Chemistry & CESAM & ECOMARE, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Catarina B Afonso
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria R M Domingues
- Mass Spectrometry Centre, Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal; Department of Chemistry & CESAM & ECOMARE, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Manuela Côrte-Real
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
| | - Maria J Sousa
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
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38
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Kumar N, Leonzino M, Hancock-Cerutti W, Horenkamp FA, Li P, Lees JA, Wheeler H, Reinisch KM, De Camilli P. VPS13A and VPS13C are lipid transport proteins differentially localized at ER contact sites. J Cell Biol 2018; 217:3625-3639. [PMID: 30093493 PMCID: PMC6168267 DOI: 10.1083/jcb.201807019] [Citation(s) in RCA: 361] [Impact Index Per Article: 60.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 07/13/2018] [Accepted: 07/17/2018] [Indexed: 01/07/2023] Open
Abstract
Structural and biochemical studies show that VPS13 family proteins are lipid transporters. VPS13A and VPS13C tether the ER to mitochondria and to endosomes/lysosomes, respectively, suggesting lipid dyshomeostasis as the cause of chorea acanthocytosis and Parkinson’s disease resulting from their mutations. Mutations in the human VPS13 genes are responsible for neurodevelopmental and neurodegenerative disorders including chorea acanthocytosis (VPS13A) and Parkinson’s disease (VPS13C). The mechanisms of these diseases are unknown. Genetic studies in yeast hinted that Vps13 may have a role in lipid exchange between organelles. In this study, we show that the N-terminal portion of VPS13 is tubular, with a hydrophobic cavity that can solubilize and transport glycerolipids between membranes. We also show that human VPS13A and VPS13C bind to the ER, tethering it to mitochondria (VPS13A), to late endosome/lysosomes (VPS13C), and to lipid droplets (both VPS13A and VPS13C). These findings identify VPS13 as a lipid transporter between the ER and other organelles, implicating defects in membrane lipid homeostasis in neurological disorders resulting from their mutations. Sequence and secondary structure similarity between the N-terminal portions of Vps13 and other proteins such as the autophagy protein ATG2 suggest lipid transport roles for these proteins as well.
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Affiliation(s)
- Nikit Kumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Marianna Leonzino
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - William Hancock-Cerutti
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - Florian A Horenkamp
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - PeiQi Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Joshua A Lees
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Heather Wheeler
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT.,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
| | - Karin M Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT .,Department of Neuroscience, Yale University School of Medicine, New Haven, CT.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT.,Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT
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39
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Abstract
Our textbook image of organelles has changed. Instead of revealing isolated cellular compartments, the picture now emerging shows organelles as largely interdependent structures that can communicate through membrane contact sites (MCSs). MCSs are sites where opposing organelles are tethered but do not fuse. MCSs provide a hybrid location where the tool kits of two different organelles can work together to perform vital cellular functions, such as lipid and ion transfer, signaling, and organelle division. Here, we focus on MCSs involving the endoplasmic reticulum (ER), an organelle forming an extensive network of cisternae and tubules. We highlight how the dynamic ER network regulates a plethora of cellular processes through MCSs with various organelles and with the plasma membrane.
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Affiliation(s)
- Haoxi Wu
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, England, UK.
| | - Gia K Voeltz
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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40
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Hanada K. Lipid transfer proteins rectify inter-organelle flux and accurately deliver lipids at membrane contact sites. J Lipid Res 2018; 59:1341-1366. [PMID: 29884707 PMCID: PMC6071762 DOI: 10.1194/jlr.r085324] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/24/2018] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum (ER) is the main center for the synthesis of various lipid types in cells, and newly synthesized lipids are delivered from the ER to other organelles. In the past decade, various lipid transfer proteins (LTPs) have been recognized as mediators of lipid transport from the ER to other organelles; inter-organelle transport occurs at membrane contact sites (MCSs) and in a nonvesicular manner. Although the intermembrane transfer reaction catalyzed by LTPs is an equilibrium reaction, various types of newly synthesized lipids are transported unidirectionally in cells. This review provides a brief history of the inter-organelle trafficking of lipids and summarizes the structural and biochemical characteristics of the ceramide transport protein (CERT) as a typical LTP acting at MCSs. In addition, this review compares several LTP-mediated inter-organelle lipid trafficking systems and proposes that LTPs generate unidirectional fluxes of specific lipids between different organelles by indirect coupling with the metabolic reactions that occur in specific organelles. Moreover, the available data also suggest that the major advantage of LTP-mediated lipid transport at MCSs may be the accuracy of delivery. Finally, how cholesterol is enriched in the plasma membrane is discussed from a thermodynamic perspective.
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Affiliation(s)
- Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan
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41
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Endo T, Tamura Y, Kawano S. Phospholipid transfer by ERMES components. Aging (Albany NY) 2018; 10:528-529. [PMID: 29706612 PMCID: PMC5940124 DOI: 10.18632/aging.101434] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 04/27/2018] [Indexed: 11/25/2022]
Affiliation(s)
- Toshiya Endo
- Kyoto Sangyo University, Faculty of Life Sciences and Institute for Protein Dynamics, Kamigamo-motoyama, Kyoto, Japan
| | - Yasushi Tamura
- Kyoto Sangyo University, Faculty of Life Sciences and Institute for Protein Dynamics, Kamigamo-motoyama, Kyoto, Japan
| | - Shin Kawano
- Kyoto Sangyo University, Faculty of Life Sciences and Institute for Protein Dynamics, Kamigamo-motoyama, Kyoto, Japan
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42
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Hirabayashi Y, Kwon SK, Paek H, Pernice WM, Paul MA, Lee J, Erfani P, Raczkowski A, Petrey DS, Pon LA, Polleux F. ER-mitochondria tethering by PDZD8 regulates Ca 2+ dynamics in mammalian neurons. Science 2018; 358:623-630. [PMID: 29097544 DOI: 10.1126/science.aan6009] [Citation(s) in RCA: 305] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 08/21/2017] [Accepted: 09/20/2017] [Indexed: 01/06/2023]
Abstract
Interfaces between organelles are emerging as critical platforms for many biological responses in eukaryotic cells. In yeast, the ERMES complex is an endoplasmic reticulum (ER)-mitochondria tether composed of four proteins, three of which contain a SMP (synaptotagmin-like mitochondrial-lipid binding protein) domain. No functional ortholog for any ERMES protein has been identified in metazoans. Here, we identified PDZD8 as an ER protein present at ER-mitochondria contacts. The SMP domain of PDZD8 is functionally orthologous to the SMP domain found in yeast Mmm1. PDZD8 was necessary for the formation of ER-mitochondria contacts in mammalian cells. In neurons, PDZD8 was required for calcium ion (Ca2+) uptake by mitochondria after synaptically induced Ca2+-release from ER and thereby regulated cytoplasmic Ca2+ dynamics. Thus, PDZD8 represents a critical ER-mitochondria tethering protein in metazoans. We suggest that ER-mitochondria coupling is involved in the regulation of dendritic Ca2+ dynamics in mammalian neurons.
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Affiliation(s)
- Yusuke Hirabayashi
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA.,Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), Tokyo, Japan
| | - Seok-Kyu Kwon
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Hunki Paek
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Wolfgang M Pernice
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Maëla A Paul
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Jinoh Lee
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Parsa Erfani
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
| | - Ashleigh Raczkowski
- Simons Electron Microscopy Center, New York Structural Biology Center (NYSBC), New York, NY 10027, USA
| | - Donald S Petrey
- Center for Computational Biology and Bioinformatics, Department of Systems Biology, Columbia University, New York, NY 10032, USA.,Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Liza A Pon
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA.,Institute of Human Nutrition, Columbia University, New York, NY 10032, USA
| | - Franck Polleux
- Department of Neuroscience, Columbia University Medical Center, Columbia University, New York, NY 10027, USA. .,Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA.,Kavli Institute for Brain Science, Columbia University, New York, NY 10027, USA
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43
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Annunziata I, Sano R, d'Azzo A. Mitochondria-associated ER membranes (MAMs) and lysosomal storage diseases. Cell Death Dis 2018; 9:328. [PMID: 29491402 PMCID: PMC5832421 DOI: 10.1038/s41419-017-0025-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/19/2017] [Accepted: 09/27/2017] [Indexed: 12/18/2022]
Abstract
Lysosomal storage diseases (LSDs) comprise a large group of disorders of catabolism, mostly due to deficiency of a single glycan-cleaving hydrolase. The consequent endo-lysosomal accumulation of undigested or partially digested substrates in cells of virtually all organs, including the nervous system, is diagnostic of these diseases and underlies pathogenesis. A subgroup of LSDs, the glycosphingolipidoses, are caused by deficiency of glycosidases that process/degrade sphingolipids and glycosphingolipids (GSLs). GSLs are among the lipid constituents of mammalian membranes, where they orderly distribute and, together with a plethora of membrane proteins, contribute to the formation of discrete membrane microdomains or lipid rafts. The composition of intracellular membranes enclosing organelles reflects that at the plasma membrane (PM). Organelles have the tendencies to tether to one another and to the PM at specific membrane contact sites that, owing to their lipid and protein content, resemble PM lipid rafts. The focus of this review is on the MAMs, mitochondria associated ER membranes, sites of juxtaposition between ER and mitochondria that function as biological hubs for the exchange of molecules and ions, and control the functional status of the reciprocal organelles. We will focus on the lipid components of the MAMs, and highlight how failure to digest or process the sialylated GSL, GM1 ganglioside, in lysosomes alters the lipid conformation and functional properties of the MAMs and leads to neuronal cell death and neurodegeneration.
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Affiliation(s)
- Ida Annunziata
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Renata Sano
- Division of Oncology and Center for Childhood Cancer Research, The Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Alessandra d'Azzo
- Department of Genetics, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.
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44
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Kawano S, Tamura Y, Kojima R, Bala S, Asai E, Michel AH, Kornmann B, Riezman I, Riezman H, Sakae Y, Okamoto Y, Endo T. Structure-function insights into direct lipid transfer between membranes by Mmm1-Mdm12 of ERMES. J Cell Biol 2017; 217:959-974. [PMID: 29279306 PMCID: PMC5839780 DOI: 10.1083/jcb.201704119] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 11/06/2017] [Accepted: 12/01/2017] [Indexed: 12/26/2022] Open
Abstract
The ER–mitochondrial encounter structure (ERMES) physically links ER and mitochondrial membranes in yeast, but it is unclear whether ERMES directly facilitates lipid exchange between these organelles. Kawano et al. reveal by reconstitution experiments that a complex of Mmm1–Mdm12, two core subunits of ERMES, functions as a minimal unit for lipid transfer between membranes. The endoplasmic reticulum (ER)–mitochondrial encounter structure (ERMES) physically links the membranes of the ER and mitochondria in yeast. Although the ER and mitochondria cooperate to synthesize glycerophospholipids, whether ERMES directly facilitates the lipid exchange between the two organelles remains controversial. Here, we compared the x-ray structures of an ERMES subunit Mdm12 from Kluyveromyces lactis with that of Mdm12 from Saccharomyces cerevisiae and found that both Mdm12 proteins possess a hydrophobic pocket for phospholipid binding. However in vitro lipid transfer assays showed that Mdm12 alone or an Mmm1 (another ERMES subunit) fusion protein exhibited only a weak lipid transfer activity between liposomes. In contrast, Mdm12 in a complex with Mmm1 mediated efficient lipid transfer between liposomes. Mutations in Mmm1 or Mdm12 impaired the lipid transfer activities of the Mdm12–Mmm1 complex and furthermore caused defective phosphatidylserine transport from the ER to mitochondrial membranes via ERMES in vitro. Therefore, the Mmm1–Mdm12 complex functions as a minimal unit that mediates lipid transfer between membranes.
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Affiliation(s)
- Shin Kawano
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan.,Japan Science and Technology Agency/Core Research for Evolutional Science and Technology, Kyoto Sangyo University, Kyoto, Japan.,Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan.,Japan Science and Technology Agency/Core Research for Evolutional Science and Technology, Nagoya University, Nagoya, Japan
| | - Yasushi Tamura
- Japan Science and Technology Agency/Core Research for Evolutional Science and Technology, Nagoya University, Nagoya, Japan.,Research Center for Materials Science, Nagoya University, Nagoya, Japan.,Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Yamagata, Japan
| | - Rieko Kojima
- Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, Yamagata, Japan
| | - Siqin Bala
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Eri Asai
- Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Agnès H Michel
- Institute of Biochemistry, ETH Zürich, Zürich, Switzerland
| | | | - Isabelle Riezman
- Department of Biochemistry, National Centre of Competence in Research Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Howard Riezman
- Department of Biochemistry, National Centre of Competence in Research Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Yoshitake Sakae
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Yuko Okamoto
- Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Japan
| | - Toshiya Endo
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan .,Japan Science and Technology Agency/Core Research for Evolutional Science and Technology, Kyoto Sangyo University, Kyoto, Japan.,Institute for Protein Dynamics, Kyoto Sangyo University, Kyoto, Japan.,Department of Chemistry, Graduate School of Science, Nagoya University, Nagoya, Japan.,Japan Science and Technology Agency/Core Research for Evolutional Science and Technology, Nagoya University, Nagoya, Japan
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45
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Koch B, Tucey TM, Lo TL, Novakovic S, Boag P, Traven A. The Mitochondrial GTPase Gem1 Contributes to the Cell Wall Stress Response and Invasive Growth of Candida albicans. Front Microbiol 2017; 8:2555. [PMID: 29326680 PMCID: PMC5742345 DOI: 10.3389/fmicb.2017.02555] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 12/08/2017] [Indexed: 01/27/2023] Open
Abstract
The interactions of mitochondria with the endoplasmic reticulum (ER) are crucial for maintaining proper mitochondrial morphology, function and dynamics. This enables cells to utilize their mitochondria optimally for energy production and anabolism, and it further provides for metabolic control over developmental decisions. In fungi, a key mechanism by which ER and mitochondria interact is via a membrane tether, the protein complex ERMES (ER-Mitochondria Encounter Structure). In the model yeast Saccharomyces cerevisiae, the mitochondrial GTPase Gem1 interacts with ERMES, and it has been proposed to regulate its activity. Here we report on the first characterization of Gem1 in a human fungal pathogen. We show that in Candida albicans Gem1 has a dominant role in ensuring proper mitochondrial morphology, and our data is consistent with Gem1 working with ERMES in this role. Mitochondrial respiration and steady state cellular phospholipid homeostasis are not impacted by inactivation of GEM1 in C. albicans. There are two major virulence-related consequences of disrupting mitochondrial morphology by GEM1 inactivation: C. albicans becomes hypersusceptible to cell wall stress, and is unable to grow invasively. In the gem1Δ/Δ mutant, it is specifically the invasive capacity of hyphae that is compromised, not the ability to transition from yeast to hyphal morphology, and this phenotype is shared with ERMES mutants. As a consequence of the hyphal invasion defect, the gem1Δ/Δ mutant is drastically hypovirulent in the worm infection model. Activation of the mitogen activated protein (MAP) kinase Cek1 is reduced in the gem1Δ/Δ mutant, and this function could explain both the susceptibility to cell wall stress and lack of invasive growth. This result establishes a new, respiration-independent mechanism of mitochondrial control over stress signaling and hyphal functions in C. albicans. We propose that ER-mitochondria interactions and the ER-Mitochondria Organizing Network (ERMIONE) play important roles in adaptive responses in fungi, in particular cell surface-related mechanisms that drive invasive growth and stress responsive behaviors that support fungal pathogenicity.
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Affiliation(s)
- Barbara Koch
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Timothy M Tucey
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Tricia L Lo
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Stevan Novakovic
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Peter Boag
- Development and Stem Cells Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Ana Traven
- Infection and Immunity Program and the Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
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46
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Bian X, Saheki Y, De Camilli P. Ca 2+ releases E-Syt1 autoinhibition to couple ER-plasma membrane tethering with lipid transport. EMBO J 2017; 37:219-234. [PMID: 29222176 DOI: 10.15252/embj.201797359] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 11/08/2017] [Accepted: 11/10/2017] [Indexed: 11/09/2022] Open
Abstract
The extended synaptotagmins (E-Syts) are endoplasmic reticulum (ER) proteins that bind the plasma membrane (PM) via C2 domains and transport lipids between them via SMP domains. E-Syt1 tethers and transports lipids in a Ca2+-dependent manner, but the role of Ca2+ in this regulation is unclear. Of the five C2 domains of E-Syt1, only C2A and C2C contain Ca2+-binding sites. Using liposome-based assays, we show that Ca2+ binding to C2C promotes E-Syt1-mediated membrane tethering by releasing an inhibition that prevents C2E from interacting with PI(4,5)P2-rich membranes, as previously suggested by studies in semi-permeabilized cells. Importantly, Ca2+ binding to C2A enables lipid transport by releasing a charge-based autoinhibitory interaction between this domain and the SMP domain. Supporting these results, E-Syt1 constructs defective in Ca2+ binding in either C2A or C2C failed to rescue two defects in PM lipid homeostasis observed in E-Syts KO cells, delayed diacylglycerol clearance from the PM and impaired Ca2+-triggered phosphatidylserine scrambling. Thus, a main effect of Ca2+ on E-Syt1 is to reverse an autoinhibited state and to couple membrane tethering with lipid transport.
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Affiliation(s)
- Xin Bian
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA.,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT, USA
| | - Yasunori Saheki
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA .,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT, USA.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT, USA .,Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA.,Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT, USA.,Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT, USA
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47
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Gustafsson R, Berntsson RPA, Martínez-Carranza M, El Tekle G, Odegrip R, Johnson EA, Stenmark P. Crystal structures of OrfX2 and P47 from a Botulinum neurotoxin OrfX-type gene cluster. FEBS Lett 2017; 591:3781-3792. [PMID: 29067689 DOI: 10.1002/1873-3468.12889] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/17/2017] [Accepted: 10/18/2017] [Indexed: 11/08/2022]
Abstract
Botulinum neurotoxins are highly toxic substances and are all encoded together with one of two alternative gene clusters, the HA or the OrfX gene cluster. Very little is known about the function and structure of the proteins encoded in the OrfX gene cluster, which in addition to the toxin contains five proteins (OrfX1, OrfX2, OrfX3, P47, and NTNH). We here present the structures of OrfX2 and P47, solved to 2.1 and 1.8 Å, respectively. We show that they belong to the TULIP protein superfamily, which are often involved in lipid binding. OrfX1 and OrfX2 were both found to bind phosphatidylinositol lipids.
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Affiliation(s)
- Robert Gustafsson
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Ronnie P-A Berntsson
- Department of Biochemistry and Biophysics, Stockholm University, Sweden.,Department of Medical Biochemistry and Biophysics, Umeå University, Sweden
| | | | - Geniver El Tekle
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Richard Odegrip
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
| | - Eric A Johnson
- Department of Bacteriology, University of Wisconsin, Madison, WI, USA
| | - Pål Stenmark
- Department of Biochemistry and Biophysics, Stockholm University, Sweden
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48
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Stefan CJ, Trimble WS, Grinstein S, Drin G, Reinisch K, De Camilli P, Cohen S, Valm AM, Lippincott-Schwartz J, Levine TP, Iaea DB, Maxfield FR, Futter CE, Eden ER, Judith D, van Vliet AR, Agostinis P, Tooze SA, Sugiura A, McBride HM. Membrane dynamics and organelle biogenesis-lipid pipelines and vesicular carriers. BMC Biol 2017; 15:102. [PMID: 29089042 PMCID: PMC5663033 DOI: 10.1186/s12915-017-0432-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Discoveries spanning several decades have pointed to vital membrane lipid trafficking pathways involving both vesicular and non-vesicular carriers. But the relative contributions for distinct membrane delivery pathways in cell growth and organelle biogenesis continue to be a puzzle. This is because lipids flow from many sources and across many paths via transport vesicles, non-vesicular transfer proteins, and dynamic interactions between organelles at membrane contact sites. This forum presents our latest understanding, appreciation, and queries regarding the lipid transport mechanisms necessary to drive membrane expansion during organelle biogenesis and cell growth.
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Affiliation(s)
- Christopher J. Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London, WC1E 6BT UK
| | - William S. Trimble
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Sergio Grinstein
- Cell Biology Program, The Hospital for Sick Children and Department of Biochemistry, University of Toronto, Toronto, Canada
| | - Guillaume Drin
- Université Côte d’Azur, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Karin Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Pietro De Camilli
- Department of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Kavli Institute for Neuroscience and Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06510 USA
| | | | | | | | - Tim P. Levine
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - David B. Iaea
- Genentech, 1 DNA Way, South San Francisco, CA 94080 USA
| | - Frederick R. Maxfield
- Department of Biochemistry, Weill Cornell Medical College, 1300 York Ave, New York, NY 10065 USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Emily R. Eden
- UCL Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL UK
| | - Delphine Judith
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Alexander R. van Vliet
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Patrizia Agostinis
- Laboratory of Cell Death Research and Therapy, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Sharon A. Tooze
- Molecular Cell Biology of Autophagy Laboratory, The Francis Crick Institute, London, UK
| | - Ayumu Sugiura
- Kobe University Graduate School of Medicine, 1-5-6 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 Japan
| | - Heidi M. McBride
- Montreal Neurological Institute, McGill University, 3801 University Avenue, Montreal, Quebec H3A 2B4 Canada
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49
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Crystal structures of Mmm1 and Mdm12-Mmm1 reveal mechanistic insight into phospholipid trafficking at ER-mitochondria contact sites. Proc Natl Acad Sci U S A 2017; 114:E9502-E9511. [PMID: 29078410 DOI: 10.1073/pnas.1715592114] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The endoplasmic reticulum (ER)-mitochondria encounter structure (ERMES) comprises mitochondrial distribution and morphology 12 (Mdm12), maintenance of mitochondrial morphology 1 (Mmm1), Mdm34, and Mdm10 and mediates physical membrane contact sites and nonvesicular lipid trafficking between the ER and mitochondria in yeast. Herein, we report two crystal structures of the synaptotagmin-like mitochondrial lipid-binding protein (SMP) domain of Mmm1 and the Mdm12-Mmm1 complex at 2.8 Å and 3.8 Å resolution, respectively. Mmm1 adopts a dimeric SMP structure augmented with two extra structural elements at the N and C termini that are involved in tight self-association and phospholipid coordination. Mmm1 binds two phospholipids inside the hydrophobic cavity, and the phosphate ion of the distal phospholipid is specifically recognized through extensive H-bonds. A positively charged concave surface on the SMP domain not only mediates ER membrane docking but also results in preferential binding to glycerophospholipids such as phosphatidylcholine (PC), phosphatidic acid (PA), phosphatidylglycerol (PG), and phosphatidylserine (PS), some of which are substrates for lipid-modifying enzymes in mitochondria. The Mdm12-Mmm1 structure reveals two Mdm12s binding to the SMP domains of the Mmm1 dimer in a pairwise head-to-tail manner. Direct association of Mmm1 and Mdm12 generates a 210-Å-long continuous hydrophobic tunnel that facilitates phospholipid transport. The Mdm12-Mmm1 complex binds all glycerophospholipids except for phosphatidylethanolamine (PE) in vitro.
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Court DA, Khetoo S, Shuvo SR, Reitmeier SD, Hausner G. In silico analysis of coevolution among ERMES proteins, Pex11, and Lam6. Can J Microbiol 2017; 63:984-997. [PMID: 28985476 DOI: 10.1139/cjm-2017-0460] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In eukaryotic cells, communication and dynamic interactions among different organelles are important for maintaining cellular homeostasis. The endoplasmic reticulum (ER) mitochondria encounter structure (ERMES) complex establishes membrane contact sites between ER and mitochondria and is essential for phospholipid transport, protein import, and mitochondrial dynamics and inheritance. In this work, in silico analyses were used to probe the intramolecular interactions in ERMES proteins and the interactions that support the ERMES complex. Based on mutual information (MI), sites of intramolecular coevolution are predicted in the core proteins Mmm1, Mdm10, Mdm12, Mdm34, the peroxisomal protein Pex11, and cytoplasmic Lam6; these sites are linked to structural features of the proteins. Intermolecular coevolution is predicted among the synaptotagmin-like mitochondrial lipid-binding protein (SMP) domains of Mmm1, Mdm12, and Mdm34. Segments of Pex11 and Lam6 also share MI with the SMP domains of Mmm1 and Mdm12 and with the N terminus of Mdm34, implicating Mdm34 as part of a hub for interactions between ERMES and other complexes. In contrast, evidence of limited intermolecular coevolution involving the outer membrane protein Mdm10 was detected only with Mmm1 and Pex11. The results support models for the organization of these interacting proteins and suggest roles for Pex11 and Lam6 in regulating complex formation.
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Affiliation(s)
- Deborah A Court
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Shivani Khetoo
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Sabbir R Shuvo
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Shayne D Reitmeier
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Georg Hausner
- Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada.,Department of Microbiology, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
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