51
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Douglass MV, McLean AB, Trent MS. Absence of YhdP, TamB, and YdbH leads to defects in glycerophospholipid transport and cell morphology in Gram-negative bacteria. PLoS Genet 2022; 18:e1010096. [PMID: 35226662 PMCID: PMC8912898 DOI: 10.1371/journal.pgen.1010096] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/10/2022] [Accepted: 02/14/2022] [Indexed: 11/19/2022] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria provides the cell with a formidable barrier that excludes external threats. The two major constituents of this asymmetric barrier are lipopolysaccharide (LPS) found in the outer leaflet, and glycerophospholipids (GPLs) in the inner leaflet. Maintaining the asymmetric nature and balance of LPS to GPLs in the OM is critical for bacterial viability. The biosynthetic pathways of LPS and GPLs are well characterized, but unlike LPS transport, how GPLs are translocated to the OM remains enigmatic. Understanding this aspect of cell envelope biology could provide a foundation for new antibacterial therapies. Here, we report that YhdP and its homologues, TamB and YdbH, members of the “AsmA-like” family, are critical for OM integrity and necessary for proper GPL transport to the OM. The absence of the two largest AsmA-like proteins (YhdP and TamB) leads to cell lysis and antibiotic sensitivity, phenotypes that are rescued by reducing LPS synthesis. We also find that yhdP, tamB double mutants shed excess LPS through outer membrane vesicles, presumably to maintain OM homeostasis when normal anterograde GPL transport is disrupted. Moreover, a yhdP, tamB, ydbH triple mutant is synthetically lethal, but if GPL transport is partially restored by overexpression of YhdP, the cell shape adjusts to accommodate increased membrane content as the cell accumulates GPLs in the IM. Our results therefore suggest a model in which “AsmA-like” proteins transport GPLs to the OM, and when hindered, changes in cell shape and shedding of excess LPS aids in maintaining OM asymmetry. Much like armor, the OM of Gram-negative bacteria serves as the cell’s first line of defense against harsh environments and toxic molecules. The two major components of the OM are LPS and GPLs. To offer effective protection, the cell must maintain the appropriate balance of LPS and GPLs at the bacterial surface. Here we report that members of the “AsmA-like” family, YhdP, TamB, and YdbH contribute to the OM barrier by aiding in GPL transport and are critical for antibiotic resistance.
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Affiliation(s)
- Martin V. Douglass
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - Amanda B. McLean
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
| | - M. Stephen Trent
- Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia, United States of America
- Department of Microbiology, College of Arts and Sciences, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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52
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Neuman SD, Jorgensen JR, Cavanagh AT, Smyth JT, Selegue JE, Emr SD, Bashirullah A. The Hob proteins are novel and conserved lipid-binding proteins at ER-PM contact sites. J Cell Sci 2022; 135:jcs259086. [PMID: 34415038 PMCID: PMC8403981 DOI: 10.1242/jcs.259086] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 07/05/2021] [Indexed: 12/11/2022] Open
Abstract
Membrane contact sites are critical junctures for organelle signaling and communication. Endoplasmic reticulum-plasma membrane (ER-PM) contact sites were the first membrane contact sites to be described; however, the protein composition and molecular function of these sites is still emerging. Here, we leverage yeast and Drosophila model systems to uncover a novel role for the Hobbit (Hob) proteins at ER-PM contact sites. We find that Hobbit localizes to ER-PM contact sites in both yeast cells and the Drosophila larval salivary glands, and this localization is mediated by an N-terminal ER membrane anchor and conserved C-terminal sequences. The C-terminus of Hobbit binds to plasma membrane phosphatidylinositols, and the distribution of these lipids is altered in hobbit mutant cells. Notably, the Hobbit protein is essential for viability in Drosophila, providing one of the first examples of a membrane contact site-localized lipid binding protein that is required for development.
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Affiliation(s)
- Sarah D. Neuman
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
| | - Jeff R. Jorgensen
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Amy T. Cavanagh
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
| | - Jeremy T. Smyth
- Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | - Jane E. Selegue
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
| | - Scott D. Emr
- Weill Institute for Cell and Molecular Biology, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14853, USA
| | - Arash Bashirullah
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
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53
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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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54
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Yuan W, Akşit A, de Boer R, Krikken AM, van der Klei IJ. Yeast Vps13 is Crucial for Peroxisome Expansion in Cells With Reduced Peroxisome-ER Contact Sites. Front Cell Dev Biol 2022; 10:842285. [PMID: 35252206 PMCID: PMC8891532 DOI: 10.3389/fcell.2022.842285] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 01/28/2022] [Indexed: 12/22/2022] Open
Abstract
In the yeast Hansenula polymorpha the peroxisomal membrane protein Pex11 and three endoplasmic reticulum localized proteins of the Pex23 family (Pex23, Pex24 and Pex32) are involved in the formation of peroxisome-ER contact sites. Previous studies suggested that these contacts are involved in non-vesicular lipid transfer and important for expansion of the peroxisomal membrane. The absence of Pex32 results in a severe peroxisomal phenotype, while cells lacking Pex11, Pex23 or Pex24 show milder defects and still are capable to form peroxisomes and grow on methanol. We performed transposon mutagenesis on H. polymorpha pex11 cells and selected mutants that lost the capacity to grow on methanol and are severely blocked in peroxisome formation. This strategy resulted in the identification of Vps13, a highly conserved contact site protein involved in bulk lipid transfer. Our data show that peroxisome formation and function is normal in cells of a vps13 single deletion strain. However, Vps13 is essential for peroxisome biogenesis in pex11. Notably, Vps13 is also required for peroxisome formation in pex23 and pex24 cells. These data suggest that Vps13 is crucial for peroxisome formation in cells with reduced peroxisome-endoplasmic reticulum contact sites and plays a redundant function in lipid transfer from the ER to peroxisomes.
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55
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Chen S, Roberts MA, Chen CY, Markmiller S, Wei HG, Yeo GW, Granneman JG, Olzmann JA, Ferro-Novick S. VPS13A and VPS13C Influence Lipid Droplet Abundance. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:25152564221125613. [PMID: 36147729 PMCID: PMC9491623 DOI: 10.1177/25152564221125613] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 08/06/2022] [Indexed: 11/16/2022]
Abstract
Lipid transfer proteins mediate the exchange of lipids between closely apposed membranes at organelle contact sites and play key roles in lipid metabolism, membrane homeostasis, and cellular signaling. A recently discovered novel family of lipid transfer proteins, which includes the VPS13 proteins (VPS13A-D), adopt a rod-like bridge conformation with an extended hydrophobic groove that enables the bulk transfer of membrane lipids for membrane growth. Loss of function mutations in VPS13A and VPS13C cause chorea acanthocytosis and Parkinson's disease, respectively. VPS13A and VPS13C localize to multiple organelle contact sites, including endoplasmic reticulum (ER) - lipid droplet (LD) contact sites, but the functional roles of these proteins in LD regulation remains mostly unexplored. Here we employ CRISPR-Cas9 genome editing to generate VPS13A and VPS13C knockout cell lines in U-2 OS cells via deletion of exon 2 and introduction of an early frameshift. Analysis of LD content in these cell lines revealed that loss of either VPS13A or VPS13C results in reduced LD abundance under oleate-stimulated conditions. These data implicate two lipid transfer proteins, VPS13A and VPS13C, in LD regulation.
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Affiliation(s)
- Shuliang Chen
- Department of Cellular and Molecular
Medicine, University of California San
Diego, La Jolla, CA, USA
| | - Melissa A. Roberts
- Department of Molecular and Cell
Biology, University of California,
Berkeley, CA, USA
- Department of Nutritional Sciences and
Toxicology, University of California,
Berkeley, CA, USA
| | - Chun-Yuan Chen
- Department of Cellular and Molecular
Medicine, University of California San
Diego, La Jolla, CA, USA
| | - Sebastian Markmiller
- Department of Cellular and Molecular
Medicine, University of California San
Diego, La Jolla, CA, USA
| | - Hong-Guang Wei
- Center for Integrative Metabolic and
Endocrine Research, Wayne State University School of
Medicine, Detroit, MI, USA
| | - Gene W. Yeo
- Department of Cellular and Molecular
Medicine, University of California San
Diego, La Jolla, CA, USA
| | - James G. Granneman
- Center for Integrative Metabolic and
Endocrine Research, Wayne State University School of
Medicine, Detroit, MI, USA
| | - James A. Olzmann
- Department of Molecular and Cell
Biology, University of California,
Berkeley, CA, USA
- Department of Nutritional Sciences and
Toxicology, University of California,
Berkeley, CA, USA
- Chan Zuckerberg Biohub, San Francisco,
CA, USA
| | - Susan Ferro-Novick
- Department of Cellular and Molecular
Medicine, University of California San
Diego, La Jolla, CA, USA
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56
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Friedman JR. Mitochondria from the Outside in: The Relationship Between Inter-Organelle Crosstalk and Mitochondrial Internal Organization. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:10.1177/25152564221133267. [PMID: 36329759 PMCID: PMC9629538 DOI: 10.1177/25152564221133267] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A fundamental role of membrane-bound organelles is the compartmentalization and organization of cellular processes. Mitochondria perform an immense number of metabolic chemical reactions and to efficiently regulate these, the organelle organizes its inner membrane into distinct morphological domains, including its characteristic cristae membranes. In recent years, a structural feature of increasing apparent importance is the inter-connection between the mitochondrial exterior and other organelles at membrane contact sites (MCSs). Mitochondria form MCSs with almost every other organelle in the cell, including the endoplasmic reticulum, lipid droplets, and lysosomes, to coordinate global cellular metabolism with mitochondrial metabolism. However, these MCSs not only facilitate the transport of metabolites between organelles, but also directly impinge on the physical shape and functional organization inside mitochondria. In this review, we highlight recent advances in our understanding of how physical connections between other organelles and mitochondria both directly and indirectly influence the internal architecture of mitochondria.
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Affiliation(s)
- Jonathan R Friedman
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA
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57
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Levine TP. Sequence Analysis and Structural Predictions of Lipid Transfer Bridges in the Repeating Beta Groove (RBG) Superfamily Reveal Past and Present Domain Variations Affecting Form, Function and Interactions of VPS13, ATG2, SHIP164, Hobbit and Tweek. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:251525642211343. [PMID: 36571082 PMCID: PMC7613979 DOI: 10.1177/25152564221134328] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Lipid transfer between organelles requires proteins that shield the hydrophobic portions of lipids as they cross the cytoplasm. In the last decade a new structural form of lipid transfer protein (LTP) has been found: long hydrophobic grooves made of beta-sheet that bridge between organelles at membrane contact sites. Eukaryotes have five families of bridge-like LTPs: VPS13, ATG2, SHIP164, Hobbit and Tweek. These are unified into a single superfamily through their bridges being composed of just one domain, called the repeating beta groove (RBG) domain, which builds into rod shaped multimers with a hydrophobic-lined groove and hydrophilic exterior. Here, sequences and predicted structures of the RBG superfamily were analyzed in depth. Phylogenetics showed that the last eukaryotic common ancestor contained all five RBG proteins, with duplicated VPS13s. The current set of long RBG protein appears to have arisen in even earlier ancestors from shorter forms with 4 RBG domains. The extreme ends of most RBG proteins have amphipathic helices that might be an adaptation for direct or indirect bilayer interaction, although this has yet to be tested. The one exception to this is the C-terminus of SHIP164, which instead has a coiled-coil. Finally, the exterior surfaces of the RBG bridges are shown to have conserved residues along most of their length, indicating sites for partner interactions almost all of which are unknown. These findings can inform future cell biological and biochemical experiments.
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58
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John Peter AT, Cheung NJ, Kornmann B. Csf1: A Putative Lipid Transport Protein Required for Homeoviscous Adaptation of the Lipidome. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:25152564221101974. [PMID: 37366504 PMCID: PMC10243558 DOI: 10.1177/25152564221101974] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/03/2022] [Indexed: 06/28/2023]
Abstract
The non-vesicular transport of lipids between organelles mediated by lipid transport proteins (LTPs) is a key determinant of organelle biogenesis and function. Despite performing a vital function in organelle homeostasis, none of the LTP-encoding genes identified so far are truly essential, even in the simple genome of yeast, suggesting widespread redundancy. In line with this fact, it has been found that a number of LTPs have overlapping functions, making it challenging to assign unique roles for an individual LTP in lipid distribution. In our genetic screens under stringent conditions in which the distinct function of an LTP might become essential, we stumbled upon Csf1, a highly conserved protein with a Chorein-N motif found in other lipid transporters and unraveled a new function for Csf1 in lipid remodeling and homeoviscous adaptation of the lipidome. Here, we further speculate on the potential mechanisms of how the putative function of Csf1 in lipid transport could be intimately connected to its role in lipid remodeling across organelles.
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59
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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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60
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Ge J, Bian X, Ma L, Cai Y, Li Y, Yang J, Karatekin E, De Camilli P, Zhang Y. Stepwise membrane binding of extended synaptotagmins revealed by optical tweezers. Nat Chem Biol 2021; 18:313-320. [PMID: 34916620 DOI: 10.1038/s41589-021-00914-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/29/2021] [Indexed: 12/15/2022]
Abstract
Extended synaptotagmins (E-Syts) mediate lipid exchange between the endoplasmic reticulum (ER) and the plasma membrane (PM). Anchored on the ER, E-Syts bind the PM via an array of C2 domains in a Ca2+- and lipid-dependent manner, drawing the two membranes close to facilitate lipid exchange. How these C2 domains bind the PM and regulate the ER-PM distance is not well understood. Here, we applied optical tweezers to dissect PM binding by E-Syt1 and E-Syt2. We detected Ca2+- and lipid-dependent membrane-binding kinetics of both E-Syts and determined the binding energies and rates of individual C2 domains or pairs. We incorporated these parameters in a theoretical model to recapitulate salient features of E-Syt-mediated membrane contacts observed in vivo, including their equilibrium distances and probabilities. Our methods can be applied to study other proteins containing multiple membrane-binding domains linked by disordered polypeptides.
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Affiliation(s)
- Jinghua Ge
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Xin Bian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, 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.,State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Lu Ma
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Nanobiology Institute, Yale University, West Haven, CT, USA.,Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Yiying Cai
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, 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
| | - Yanghui Li
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,College of Optical and Electronic Technology, China Jiliang University, Hangzhou, China
| | - Jie Yang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Erdem Karatekin
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Nanobiology Institute, Yale University, West Haven, CT, USA.,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.,Université de Paris, Saints-Pères Paris Institute for the Neurosciences (SPPIN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Pietro De Camilli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Department of Neuroscience, 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
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA. .,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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61
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Renne MF, Bao X, Hokken MW, Bierhuizen AS, Hermansson M, Sprenger RR, Ewing TA, Ma X, Cox RC, Brouwers JF, De Smet CH, Ejsing CS, de Kroon AI. Molecular species selectivity of lipid transport creates a mitochondrial sink for di-unsaturated phospholipids. EMBO J 2021; 41:e106837. [PMID: 34873731 PMCID: PMC8762554 DOI: 10.15252/embj.2020106837] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 10/22/2021] [Accepted: 10/26/2021] [Indexed: 11/09/2022] Open
Abstract
Mitochondria depend on the import of phospholipid precursors for the biosynthesis of phosphatidylethanolamine (PE) and cardiolipin, yet the mechanism of their transport remains elusive. A dynamic lipidomics approach revealed that mitochondria preferentially import di-unsaturated phosphatidylserine (PS) for subsequent conversion to PE by the mitochondrial PS decarboxylase Psd1p. Several protein complexes tethering mitochondria to the endomembrane system have been implicated in lipid transport in yeast, including the endoplasmic reticulum (ER)-mitochondrial encounter structure (ERMES), ER-membrane complex (EMC), and the vacuole and mitochondria patch (vCLAMP). By limiting the availability of unsaturated phospholipids, we created conditions to investigate the mechanism of lipid transfer and the contributions of the tethering complexes in vivo. Under these conditions, inactivation of ERMES components or of the vCLAMP component Vps39p exacerbated accumulation of saturated lipid acyl chains, indicating that ERMES and Vps39p contribute to the mitochondrial sink for unsaturated acyl chains by mediating transfer of di-unsaturated phospholipids. These results support the concept that intermembrane lipid flow is rate-limited by molecular species-dependent lipid efflux from the donor membrane and driven by the lipid species' concentration gradient between donor and acceptor membrane.
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Affiliation(s)
- Mike F Renne
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Xue Bao
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Margriet Wj Hokken
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Adolf S Bierhuizen
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Martin Hermansson
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Richard R Sprenger
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Tom A Ewing
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Xiao Ma
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Ruud C Cox
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Jos F Brouwers
- Biochemistry and Cell Biology, Department of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Cedric H De Smet
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Christer S Ejsing
- Department of Biochemistry and Molecular Biology, VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark.,Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Anton Ipm de Kroon
- Membrane Biochemistry & Biophysics, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
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62
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De Camilli P. How a first research experience had an impact on my scientific journey. Mol Biol Cell 2021; 32:ae1. [PMID: 34735266 PMCID: PMC8694089 DOI: 10.1091/mbc.e21-08-0397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
As I look back to my scientific trajectory on the occasion of being the recipient of the E. B. Wilson Medal of the American Society for Cell Biology, I realize how much an early scientific experience had an impact on my research many years later. The major influence that the first scientific encounters can have in defining a scientist’s path makes the choice of the training environment so important for a future career.
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Affiliation(s)
- Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510
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63
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YhdP, TamB, and YdbH Are Redundant but Essential for Growth and Lipid Homeostasis of the Gram-Negative Outer Membrane. mBio 2021; 12:e0271421. [PMID: 34781743 PMCID: PMC8593681 DOI: 10.1128/mbio.02714-21] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The bacterial cell envelope is the first line of defense and point of contact with the environment and other organisms. Envelope biogenesis is therefore crucial for the survival and physiology of bacteria and is often targeted by antimicrobials. Gram-negative bacteria have a multilayered envelope delimited by an inner and outer membrane (IM and OM, respectively). The OM is a barrier against many antimicrobials because of its asymmetric lipid structure, with phospholipids composing the inner leaflet and lipopolysaccharides (LPS) the outer leaflet. Since lipid synthesis occurs at the IM, phospholipids and LPS are transported across the cell envelope and asymmetrically assembled at the OM during growth. How phospholipids are transported to the OM remains unknown. Recently, the Escherichia coli protein YhdP has been proposed to participate in this process through an unknown mechanism. YhdP belongs to the AsmA-like clan and contains domains homologous to those found in lipid transporters. Here, we used genetics to investigate the six members of the AsmA-like clan of proteins in E. coli. Our data show that YhdP and its paralogs TamB and YdbH are redundant, but not equivalent, in performing an essential function in the cell envelope. Among the AsmA-like paralogs, only the combined loss of YhdP, TamB, and YdbH is lethal, and any of these three proteins is sufficient for growth. We also show that these proteins are required for OM lipid homeostasis and propose that they are the long-sought-after phospholipid transporters that are required for OM biogenesis.
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64
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The GTPase Arf1 Is a Determinant of Yeast Vps13 Localization to the Golgi Apparatus. Int J Mol Sci 2021; 22:ijms222212274. [PMID: 34830155 PMCID: PMC8619211 DOI: 10.3390/ijms222212274] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/08/2021] [Accepted: 11/10/2021] [Indexed: 12/12/2022] Open
Abstract
VPS13 proteins are evolutionarily conserved. Mutations in the four human genes (VPS13A-D) encoding VPS13A-D proteins are linked to developmental or neurodegenerative diseases. The relationship between the specific localization of individual VPS13 proteins, their molecular functions, and the pathology of these diseases is unknown. Here we used a yeast model to establish the determinants of Vps13's interaction with the membranes of Golgi apparatus. We analyzed the different phenotypes of the arf1-3 arf2Δ vps13∆ strain, with reduced activity of the Arf1 GTPase, the master regulator of Golgi function and entirely devoid of Vps13. Our analysis led us to propose that Vps13 and Arf1 proteins cooperate at the Golgi apparatus. We showed that Vps13 binds to the Arf1 GTPase through its C-terminal Pleckstrin homology (PH)-like domain. This domain also interacts with phosphoinositol 4,5-bisphosphate as it was bound to liposomes enriched with this lipid. The homologous domain of VPS13A exhibited the same behavior. Furthermore, a fusion of the PH-like domain of Vps13 to green fluorescent protein was localized to Golgi structures in an Arf1-dependent manner. These results suggest that the PH-like domains and Arf1 are determinants of the localization of VPS13 proteins to the Golgi apparatus in yeast and humans.
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Iovine JC, Claypool SM, Alder NN. Mitochondrial compartmentalization: emerging themes in structure and function. Trends Biochem Sci 2021; 46:902-917. [PMID: 34244035 PMCID: PMC11008732 DOI: 10.1016/j.tibs.2021.06.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/26/2021] [Accepted: 06/04/2021] [Indexed: 11/27/2022]
Abstract
Within cellular structures, compartmentalization is the concept of spatial segregation of macromolecules, metabolites, and biochemical pathways. Therefore, this concept bridges organellar structure and function. Mitochondria are morphologically complex, partitioned into several subcompartments by a topologically elaborate two-membrane system. They are also dynamically polymorphic, undergoing morphogenesis events with an extent and frequency that is only now being appreciated. Thus, mitochondrial compartmentalization is something that must be considered both spatially and temporally. Here, we review new developments in how mitochondrial structure is established and regulated, the factors that underpin the distribution of lipids and proteins, and how they spatially demarcate locations of myriad mitochondrial processes. Consistent with its pre-eminence, disturbed mitochondrial compartmentalization contributes to the dysfunction associated with heritable and aging-related diseases.
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Affiliation(s)
- Joseph C Iovine
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Steven M Claypool
- Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nathan N Alder
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
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66
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Ferreira JV, Carvalho P. Pex30-like proteins function as adaptors at distinct ER membrane contact sites. J Cell Biol 2021; 220:212563. [PMID: 34402813 PMCID: PMC8374871 DOI: 10.1083/jcb.202103176] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/19/2021] [Accepted: 07/20/2021] [Indexed: 12/20/2022] Open
Abstract
Membrane lipids and proteins synthesized in the ER are used for de novo assembly of organelles, such as lipid droplets and peroxisomes. After assembly, the growth of these organelles is supported by ER-derived lipids transferred at membrane contact sites (MCSs). How ER sites for organelle biogenesis and lipid transfer are established and regulated is unclear. Here, we investigate how the ER membrane protein Pex30 and its family members Pex28, Pex29, Pex31, and Pex32 target and function at multiple MCSs. We show that different Pex30 complexes function at distinct ER domains and MCSs. Pex30 targets ER–peroxisome MCSs when bound to Pex28 and Pex32, organizes the nuclear–vacuolar junction when bound to Pex29, and promotes the biogenesis of lipid droplets independently of other family members. Importantly, the reticulon homology domain (RHD) mediates the assembly of the various Pex30 complexes. Given the role of RHD in membrane shaping, our findings offer a mechanistic link between MCS and regulation of membrane curvature.
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Affiliation(s)
| | - Pedro Carvalho
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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67
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Leonzino M, Reinisch KM, De Camilli P. Insights into VPS13 properties and function reveal a new mechanism of eukaryotic lipid transport. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159003. [PMID: 34216812 PMCID: PMC8325632 DOI: 10.1016/j.bbalip.2021.159003] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 02/06/2023]
Abstract
The occurrence of protein mediated lipid transfer between intracellular membranes has been known since the late 1960's. Since these early discoveries, numerous proteins responsible for such transport, which often act at membrane contact sites, have been identified. Typically, they comprise a lipid harboring module thought to shuttle back and forth between the two adjacent bilayers. Recently, however, studies of the chorein domain protein family, which includes VPS13 and ATG2, has led to the identification of a novel mechanism of lipid transport between organelles in eukaryotic cells mediated by a rod-like protein bridge with a hydrophobic groove through which lipids can slide. This mechanism is ideally suited for bulk transport of bilayer lipids to promote membrane growth. Here we describe how studies of VPS13 led to the discovery of this new mechanism, summarize properties and known roles of VPS13 proteins, and discuss how their dysfunction may lead to disease.
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Affiliation(s)
- Marianna Leonzino
- Department of Neuroscience, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, USA; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA; CNR Institute of Neuroscience, Milan, Italy and Humanitas Clinical and Research Center, Rozzano, MI, Italy.
| | - Karin M Reinisch
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Pietro De Camilli
- Department of Neuroscience, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, USA; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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68
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Lenoir G, D'Ambrosio JM, Dieudonné T, Čopič A. Transport Pathways That Contribute to the Cellular Distribution of Phosphatidylserine. Front Cell Dev Biol 2021; 9:737907. [PMID: 34540851 PMCID: PMC8440936 DOI: 10.3389/fcell.2021.737907] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/10/2021] [Indexed: 12/05/2022] Open
Abstract
Phosphatidylserine (PS) is a negatively charged phospholipid that displays a highly uneven distribution within cellular membranes, essential for establishment of cell polarity and other processes. In this review, we discuss how combined action of PS biosynthesis enzymes in the endoplasmic reticulum (ER), lipid transfer proteins (LTPs) acting within membrane contact sites (MCS) between the ER and other compartments, and lipid flippases and scramblases that mediate PS flip-flop between membrane leaflets controls the cellular distribution of PS. Enrichment of PS in specific compartments, in particular in the cytosolic leaflet of the plasma membrane (PM), requires input of energy, which can be supplied in the form of ATP or by phosphoinositides. Conversely, coupling between PS synthesis or degradation, PS flip-flop and PS transfer may enable PS transfer by passive flow. Such scenario is best documented by recent work on the formation of autophagosomes. The existence of lateral PS nanodomains, which is well-documented in the case of the PM and postulated for other compartments, can change the steepness or direction of PS gradients between compartments. Improvements in cellular imaging of lipids and membranes, lipidomic analysis of complex cellular samples, reconstitution of cellular lipid transport reactions and high-resolution structural data have greatly increased our understanding of cellular PS homeostasis. Our review also highlights how budding yeast has been instrumental for our understanding of the organization and transport of PS in cells.
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Affiliation(s)
- Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Juan Martín D'Ambrosio
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
| | - Thibaud Dieudonné
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alenka Čopič
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
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69
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Reinisch KM, Prinz WA. Mechanisms of nonvesicular lipid transport. J Cell Biol 2021; 220:211813. [PMID: 33605998 PMCID: PMC7901144 DOI: 10.1083/jcb.202012058] [Citation(s) in RCA: 71] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 12/18/2022] Open
Abstract
We have long known that lipids traffic between cellular membranes via vesicles but have only recently appreciated the role of nonvesicular lipid transport. Nonvesicular transport can be high volume, supporting biogenesis of rapidly expanding membranes, or more targeted and precise, allowing cells to rapidly alter levels of specific lipids in membranes. Most such transport probably occurs at membrane contact sites, where organelles are closely apposed, and requires lipid transport proteins (LTPs), which solubilize lipids to shield them from the aqueous phase during their transport between membranes. Some LTPs are cup like and shuttle lipid monomers between membranes. Others form conduits allowing lipid flow between membranes. This review describes what we know about nonvesicular lipid transfer mechanisms while also identifying many remaining unknowns: How do LTPs facilitate lipid movement from and into membranes, do LTPs require accessory proteins for efficient transfer in vivo, and how is directionality of transport determined?
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Affiliation(s)
- Karin M Reinisch
- Department of Cell Biology, Yale School of Medicine, New Haven, CT
| | - William A Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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Nakamura TS, Suda Y, Muneshige K, Fujieda Y, Okumura Y, Inoue I, Tanaka T, Takahashi T, Nakanishi H, Gao XD, Okada Y, Neiman AM, Tachikawa H. Suppression of Vps13 adaptor protein mutants reveals a central role for PI4P in regulating prospore membrane extension. PLoS Genet 2021; 17:e1009727. [PMID: 34407079 PMCID: PMC8372973 DOI: 10.1371/journal.pgen.1009727] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/20/2021] [Indexed: 01/19/2023] Open
Abstract
Vps13 family proteins are proposed to function in bulk lipid transfer between membranes, but little is known about their regulation. During sporulation of Saccharomyces cerevisiae, Vps13 localizes to the prospore membrane (PSM) via the Spo71–Spo73 adaptor complex. We previously reported that loss of any of these proteins causes PSM extension and subsequent sporulation defects, yet their precise function remains unclear. Here, we performed a genetic screen and identified genes coding for a fragment of phosphatidylinositol (PI) 4-kinase catalytic subunit and PI 4-kinase noncatalytic subunit as multicopy suppressors of spo73Δ. Further genetic and cytological analyses revealed that lowering PI4P levels in the PSM rescues the spo73Δ defects. Furthermore, overexpression of VPS13 and lowering PI4P levels synergistically rescued the defect of a spo71Δ spo73Δ double mutant, suggesting that PI4P might regulate Vps13 function. In addition, we show that an N-terminal fragment of Vps13 has affinity for the endoplasmic reticulum (ER), and ER-plasma membrane (PM) tethers localize along the PSM in a manner dependent on Vps13 and the adaptor complex. These observations suggest that Vps13 and the adaptor complex recruit ER-PM tethers to ER-PSM contact sites. Our analysis revealed that involvement of a phosphoinositide, PI4P, in regulation of Vps13, and also suggest that distinct contact site proteins function cooperatively to promote de novo membrane formation. Vps13 family proteins are conserved lipid transfer proteins that function at organelle contact sites and have been implicated in a number of different neurological diseases. In the yeast Saccharomyces cerevisiae, Vps13 is encoded by a single gene and is localized to various contact sites by interaction with different adaptor proteins and/or lipids, however its regulation is yet to be clarified. We have previously shown that during the developmental process of sporulation, Vps13 is recruited to de novo membrane structures called prospore membranes (PSMs) by a specific adaptor complex, and Vps13 and its adaptors are required for PSM extension. Here we reveal that loss of an adaptor can be overcome by lowering phosphatidylinositol-4-phosphate (PI4P) levels, either by inhibiting PI 4-kinase on the PSM or recruiting PI 4-phospatase to the PSM and that PI4P levels in the PSM affect Vps13 function. Further, we show that Vps13 forms endoplasmic reticulum (ER)-PSM contact sites, that ER-plasma membrane tethering proteins are recruited to ER-PSM contacts, and these proteins may function in conjunction with Vps13. Thus, our work shines light on both the mechanisms of intracellular remodeling and the function of this important class of lipid transfer proteins.
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Affiliation(s)
- Tsuyoshi S. Nakamura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Kanagawa, Japan
| | - Yasuyuki Suda
- Department of Molecular Cell Biology, Graduate School of Comprehensive Human Sciences and Institute of Basic Medical Sciences, University of Tsukuba, Ibaraki, Japan
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Kenji Muneshige
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Fujieda
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuuya Okumura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Ichiro Inoue
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Takayuki Tanaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tetsuo Takahashi
- Laboratory of Glycobiology and Glycotechnology, Department of Applied Biochemistry, School of Engineering, Tokai University, Kanagawa, Japan
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yasushi Okada
- Laboratory for Cell Dynamics Observation, Center for Biosystems Dynamics Research, RIKEN, Osaka, Japan
- Department of Physics and Universal Biology Institute, Graduate School of Science, The University of Tokyo, Tokyo, Japan
- Department of Physics, Universal Biology Institute, and the International Research Center for Neurointelligence (WPI-IRCN), The University of Tokyo, Tokyo, Japan
| | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, United States of America
| | - Hiroyuki Tachikawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, Tokyo, Japan
- * E-mail:
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Kaminska J, Zoladek T. Yeast Models and Molecular Mechanisms of Neurodegenerative Diseases. Int J Mol Sci 2021; 22:ijms22168775. [PMID: 34445483 PMCID: PMC8395755 DOI: 10.3390/ijms22168775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 12/13/2022] Open
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Mitochondrial fission, integrity and completion of mitophagy require separable functions of Vps13D in Drosophila neurons. PLoS Genet 2021; 17:e1009731. [PMID: 34383748 PMCID: PMC8384225 DOI: 10.1371/journal.pgen.1009731] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 08/24/2021] [Accepted: 07/21/2021] [Indexed: 11/19/2022] Open
Abstract
A healthy population of mitochondria, maintained by proper fission, fusion, and degradation, is critical for the long-term survival and function of neurons. Here, our discovery of mitophagy intermediates in fission-impaired Drosophila neurons brings new perspective into the relationship between mitochondrial fission and mitophagy. Neurons lacking either the ataxia disease gene Vps13D or the dynamin related protein Drp1 contain enlarged mitochondria that are engaged with autophagy machinery and also lack matrix components. Reporter assays combined with genetic studies imply that mitophagy both initiates and is completed in Drp1 impaired neurons, but fails to complete in Vps13D impaired neurons, which accumulate compromised mitochondria within stalled mito-phagophores. Our findings imply that in fission-defective neurons, mitophagy becomes induced, and that the lipid channel containing protein Vps13D has separable functions in mitochondrial fission and phagophore elongation.
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Genetic Dissection of Vps13 Regulation in Yeast Using Disease Mutations from Human Orthologs. Int J Mol Sci 2021; 22:ijms22126200. [PMID: 34201352 PMCID: PMC8229349 DOI: 10.3390/ijms22126200] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/03/2021] [Accepted: 06/06/2021] [Indexed: 01/03/2023] Open
Abstract
The VPS13 family of proteins have emerged as key players in intracellular lipid transport and human health. Humans have four different VPS13 orthologs, the dysfunction of which leads to different diseases. Yeast has a single VPS13 gene, which encodes a protein that localizes to multiple different membrane contact sites. The yeast vps13Δ mutant is pleiotropic, exhibiting defects in sporulation, protein trafficking, endoplasmic reticulum (ER)-phagy and mitochondrial function. Non-null alleles resulting from missense mutations can be useful reagents for understanding the multiple functions of a gene. The exceptionally large size of Vps13 makes the identification of key residues challenging. As a means to identify critical residues in yeast Vps13, amino acid substitution mutations from VPS13A, B, C and D, associated with human disease, were introduced at the cognate positions of yeast VPS13, some of which created separation-of-function alleles. Phenotypic analyses of these mutants have revealed that the promotion of ER-phagy is a fourth, genetically separable role of VPS13 and provide evidence that co-adaptors at the endosome mediate the activity of VPS13 in vacuolar sorting.
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74
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de la Mora E, Dezi M, Di Cicco A, Bigay J, Gautier R, Manzi J, Polidori J, Castaño-Díez D, Mesmin B, Antonny B, Lévy D. Nanoscale architecture of a VAP-A-OSBP tethering complex at membrane contact sites. Nat Commun 2021; 12:3459. [PMID: 34103503 PMCID: PMC8187361 DOI: 10.1038/s41467-021-23799-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2020] [Accepted: 05/12/2021] [Indexed: 02/05/2023] Open
Abstract
Membrane contact sites (MCS) are subcellular regions where two organelles appose their membranes to exchange small molecules, including lipids. Structural information on how proteins form MCS is scarce. We designed an in vitro MCS with two membranes and a pair of tethering proteins suitable for cryo-tomography analysis. It includes VAP-A, an ER transmembrane protein interacting with a myriad of cytosolic proteins, and oxysterol-binding protein (OSBP), a lipid transfer protein that transports cholesterol from the ER to the trans Golgi network. We show that VAP-A is a highly flexible protein, allowing formation of MCS of variable intermembrane distance. The tethering part of OSBP contains a central, dimeric, and helical T-shape region. We propose that the molecular flexibility of VAP-A enables the recruitment of partners of different sizes within MCS of adjustable thickness, whereas the T geometry of the OSBP dimer facilitates the movement of the two lipid-transfer domains between membranes.
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Affiliation(s)
- Eugenio de la Mora
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France
- Sorbonne Université, Paris, France
| | - Manuela Dezi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.
- Sorbonne Université, Paris, France.
| | - Aurélie Di Cicco
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France
- Sorbonne Université, Paris, France
| | - Joëlle Bigay
- CNRS UMR 7275, Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Romain Gautier
- CNRS UMR 7275, Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - John Manzi
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France
- Sorbonne Université, Paris, France
| | - Joël Polidori
- CNRS UMR 7275, Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | | | - Bruno Mesmin
- CNRS UMR 7275, Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Bruno Antonny
- CNRS UMR 7275, Université Côte d'Azur, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France.
| | - Daniel Lévy
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR168, Paris, France.
- Sorbonne Université, Paris, France.
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Guillén-Samander A, Leonzino M, Hanna MG, Tang N, Shen H, De Camilli P. VPS13D bridges the ER to mitochondria and peroxisomes via Miro. J Cell Biol 2021; 220:e202010004. [PMID: 33891013 PMCID: PMC8077184 DOI: 10.1083/jcb.202010004] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 01/08/2021] [Accepted: 02/17/2021] [Indexed: 12/12/2022] Open
Abstract
Mitochondria, which are excluded from the secretory pathway, depend on lipid transport proteins for their lipid supply from the ER, where most lipids are synthesized. In yeast, the outer mitochondrial membrane GTPase Gem1 is an accessory factor of ERMES, an ER-mitochondria tethering complex that contains lipid transport domains and that functions, partially redundantly with Vps13, in lipid transfer between the two organelles. In metazoa, where VPS13, but not ERMES, is present, the Gem1 orthologue Miro was linked to mitochondrial dynamics but not to lipid transport. Here we show that Miro, including its peroxisome-enriched splice variant, recruits the lipid transport protein VPS13D, which in turn binds the ER in a VAP-dependent way and thus could provide a lipid conduit between the ER and mitochondria. These findings reveal a so far missing link between function(s) of Gem1/Miro in yeast and higher eukaryotes, where Miro is a Parkin substrate, with potential implications for Parkinson's disease pathogenesis.
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Affiliation(s)
- Andrés Guillén-Samander
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Marianna Leonzino
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Michael G. Hanna
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Ni Tang
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Hongying Shen
- Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT
- Systems Biology Institute, Yale West Campus, West Haven, CT
| | - Pietro De Camilli
- Departments of Neuroscience and of Cell Biology, Howard Hughes Medical Institute, 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
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD
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76
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Venditti R, Wilson C, De Matteis MA. Regulation and physiology of membrane contact sites. Curr Opin Cell Biol 2021; 71:148-157. [PMID: 33932623 DOI: 10.1016/j.ceb.2021.03.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/18/2021] [Accepted: 03/22/2021] [Indexed: 12/14/2022]
Abstract
Membrane contact sites (MCSs) in addition to impacting the functions of membrane-limited organelles also have a role in the spatial and functional organization of cells, tissues and whole organisms. MCSs have been identified between all organelles and the identification of their molecular composition has progressed significantly in recent years. Equally important is how MCSs respond dynamically to physiological stimuli, how this is regulated, and the physiological roles of MCSs in tissues and at the organismal level, an area that still remains relatively unexplored. In the present review, we focus on the regulation of MCSs, considerations of their function at the organismal level, and how mutations of MCS components linked to genetic diseases might inform us about their physiological relevance.
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Affiliation(s)
- Rossella Venditti
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Napoli Federico II-Medical School, Naples, Italy
| | - Cathal Wilson
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy; Department of Molecular Medicine and Medical Biotechnology, University of Napoli Federico II-Medical School, Naples, Italy.
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77
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Autophagosome biogenesis comes out of the black box. Nat Cell Biol 2021; 23:450-456. [PMID: 33903736 DOI: 10.1038/s41556-021-00669-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/23/2021] [Indexed: 02/08/2023]
Abstract
Macroautophagic clearance of cytosolic materials entails the initiation, growth and closure of autophagosomes. Cargo triggers the assembly of a web of cargo receptors and core machinery. Autophagy-related protein 9 (ATG9) vesicles seed the growing autophagosomal membrane, which is supplied by de novo phospholipid synthesis, phospholipid transport via ATG2 proteins and lipid flipping by ATG9. Autophagosomes close via ESCRT complexes. Here, we review recent discoveries that illuminate the molecular mechanisms of autophagosome formation and discuss emerging questions in this rapidly developing field.
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78
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Gao Y, Xiong J, Chu QZ, Ji WK. PDZD8-mediated lipid transfer at contacts between the ER and late endosomes/lysosomes is required for neurite outgrowth. J Cell Sci 2021; 135:256568. [PMID: 33912962 DOI: 10.1242/jcs.255026] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/17/2021] [Indexed: 12/22/2022] Open
Abstract
Membrane contact sites (MCSs) between the endoplasmic reticulum (ER) and late endosomes/lysosomes (LE/lys) are emerging as critical hubs for diverse cellular events, and changes in their extents are linked to severe neurological diseases. While recent studies show that the synaptotagmin-like mitochondrial-lipid-binding (SMP) domain-containing protein PDZD8 may mediate the formation of ER-LE/lys MCSs, the cellular functions of PDZD8 remain largely elusive. Here, we attempt to investigate the lipid transfer activities of PDZD8 and the extent to which its cellular functions depend on its lipid transfer activities. In accordance with recent studies, we demonstrate that PDZD8 is a protrudin (ZFYVE27)-interacting protein and that PDZD8 acts as a tether at ER-LE/lys MCSs. Furthermore, we discover that the SMP domain of PDZD8 binds glycerophospholipids and ceramides both in vivo and in vitro, and that the SMP domain can transport lipids between membranes in vitro. Functionally, PDZD8 is required for LE/lys positioning and neurite outgrowth, which is dependent on the lipid transfer activity of the SMP domain.
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Affiliation(s)
- Yuan Gao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Juan Xiong
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Qing-Zhu Chu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Wei-Ke Ji
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
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79
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Abstract
Our cells are comprised of billions of proteins, lipids, and other small molecules packed into their respective subcellular organelles, with the daunting task of maintaining cellular homeostasis over a lifetime. However, it is becoming increasingly evident that organelles do not act as autonomous discrete units but rather as interconnected hubs that engage in extensive communication through membrane contacts. In the last few years, our understanding of how these contacts coordinate organelle function has redefined our view of the cell. This review aims to present novel findings on the cellular interorganelle communication network and how its dysfunction may contribute to aging and neurodegeneration. The consequences of disturbed interorganellar communication are intimately linked with age-related pathologies. Given that both aging and neurodegenerative diseases are characterized by the concomitant failure of multiple cellular pathways, coordination of organelle communication and function could represent an emerging regulatory mechanism critical for long-term cellular homeostasis. We anticipate that defining the relationships between interorganelle communication, aging, and neurodegeneration will open new avenues for therapeutics.
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Affiliation(s)
- Maja Petkovic
- Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA
| | - Caitlin E O'Brien
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
| | - Yuh Nung Jan
- Department of Physiology, University of California at San Francisco, San Francisco, California 94158, USA
- Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California 94158, USA
- Department of Biochemistry and Biophysics, University of California at San Francisco, San Francisco, California 94158, USA
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80
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Tirrell PS, Nguyen KN, Luby-Phelps K, Friedman JR. MICOS subcomplexes assemble independently on the mitochondrial inner membrane in proximity to ER contact sites. J Cell Biol 2021; 219:211445. [PMID: 33053165 PMCID: PMC7545361 DOI: 10.1083/jcb.202003024] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/05/2020] [Accepted: 09/08/2020] [Indexed: 12/23/2022] Open
Abstract
MICOS is a conserved multisubunit complex that localizes to mitochondrial cristae junctions and organizes cristae positioning within the organelle. MICOS is organized into two independent subcomplexes; however, the mechanisms that dictate the assembly and spatial positioning of each MICOS subcomplex are poorly understood. Here, we determine that MICOS subcomplexes target independently of one another to sites on the inner mitochondrial membrane that are in proximity to contact sites between mitochondria and the ER. One subcomplex, composed of Mic27/Mic26/Mic10/Mic12, requires ERMES complex function for its assembly. In contrast, the principal MICOS component, Mic60, self-assembles and localizes in close proximity to the ER through an independent mechanism. We also find that Mic60 can uniquely redistribute adjacent to forced mitochondria-vacuole contact sites. Our data suggest that nonoverlapping properties of interorganelle contact sites provide spatial cues that enable MICOS assembly and ultimately lead to proper physical and functional organization of mitochondria.
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Affiliation(s)
- Parker S Tirrell
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Kailey N Nguyen
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Katherine Luby-Phelps
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jonathan R Friedman
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX
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81
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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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82
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Melia TJ, Lystad AH, Simonsen A. Autophagosome biogenesis: From membrane growth to closure. J Cell Biol 2021; 219:151729. [PMID: 32357219 PMCID: PMC7265318 DOI: 10.1083/jcb.202002085] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 12/14/2022] Open
Abstract
Autophagosome biogenesis involves de novo formation of a membrane that elongates to sequester cytoplasmic cargo and closes to form a double-membrane vesicle (an autophagosome). This process has remained enigmatic since its initial discovery >50 yr ago, but our understanding of the mechanisms involved in autophagosome biogenesis has increased substantially during the last 20 yr. Several key questions do remain open, however, including, What determines the site of autophagosome nucleation? What is the origin and lipid composition of the autophagosome membrane? How is cargo sequestration regulated under nonselective and selective types of autophagy? This review provides key insight into the core molecular mechanisms underlying autophagosome biogenesis, with a specific emphasis on membrane modeling events, and highlights recent conceptual advances in the field.
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Affiliation(s)
- Thomas J Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Alf H Lystad
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences and Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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83
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Dziurdzik SK, Conibear E. The Vps13 Family of Lipid Transporters and Its Role at Membrane Contact Sites. Int J Mol Sci 2021; 22:ijms22062905. [PMID: 33809364 PMCID: PMC7999203 DOI: 10.3390/ijms22062905] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 12/27/2022] Open
Abstract
The conserved VPS13 proteins constitute a new family of lipid transporters at membrane contact sites. These large proteins are suspected to bridge membranes and form a direct channel for lipid transport between organelles. Mutations in the 4 human homologs (VPS13A–D) are associated with a number of neurological disorders, but little is known about their precise functions or the relevant contact sites affected in disease. In contrast, yeast has a single Vps13 protein which is recruited to multiple organelles and contact sites. The yeast model system has proved useful for studying the function of Vps13 at different organelles and identifying the localization determinants responsible for its membrane targeting. In this review we describe recent advances in our understanding of VPS13 proteins with a focus on yeast research.
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Affiliation(s)
- Samantha Katarzyna Dziurdzik
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada;
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia, Vancouver, BC V5Z 4H4, Canada;
- Department of Medical Genetics, Faculty of Medicine, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
- Correspondence:
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84
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Soczewka P, Tribouillard-Tanvier D, di Rago JP, Zoladek T, Kaminska J. Targeting Copper Homeostasis Improves Functioning of vps13Δ Yeast Mutant Cells, a Model of VPS13-Related Diseases. Int J Mol Sci 2021; 22:2248. [PMID: 33668157 PMCID: PMC7956333 DOI: 10.3390/ijms22052248] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/12/2021] [Accepted: 02/19/2021] [Indexed: 01/01/2023] Open
Abstract
Ion homeostasis is crucial for organism functioning, and its alterations may cause diseases. For example, copper insufficiency and overload are associated with Menkes and Wilson's diseases, respectively, and iron imbalance is observed in Parkinson's and Alzheimer's diseases. To better understand human diseases, Saccharomyces cerevisiae yeast are used as a model organism. In our studies, we used the vps13Δ yeast strain as a model of rare neurological diseases caused by mutations in VPS13A-D genes. In this work, we show that overexpression of genes encoding copper transporters, CTR1, CTR3, and CCC2, or the addition of copper salt to the medium, improved functioning of the vps13Δ mutant. We show that their mechanism of action, at least partially, depends on increasing iron content in the cells by the copper-dependent iron uptake system. Finally, we present that treatment with copper ionophores, disulfiram, elesclomol, and sodium pyrithione, also resulted in alleviation of the defects observed in vps13Δ cells. Our study points at copper and iron homeostasis as a potential therapeutic target for further investigation in higher eukaryotic models of VPS13-related diseases.
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Affiliation(s)
- Piotr Soczewka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Déborah Tribouillard-Tanvier
- IBGC, UMR 5095, CNRS, Université de Bordeaux, F-33000 Bordeaux, France; (D.T.-T.); (J.-P.d.R.)
- Institut National de la Santé et de la Recherche Médicale (INSERM), F-33077 Bordeaux, France
| | - Jean-Paul di Rago
- IBGC, UMR 5095, CNRS, Université de Bordeaux, F-33000 Bordeaux, France; (D.T.-T.); (J.-P.d.R.)
| | - Teresa Zoladek
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Joanna Kaminska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland;
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85
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Wang J, Fang N, Xiong J, Du Y, Cao Y, Ji WK. An ESCRT-dependent step in fatty acid transfer from lipid droplets to mitochondria through VPS13D-TSG101 interactions. Nat Commun 2021; 12:1252. [PMID: 33623047 PMCID: PMC7902631 DOI: 10.1038/s41467-021-21525-5] [Citation(s) in RCA: 63] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 02/01/2021] [Indexed: 12/13/2022] Open
Abstract
Upon starvation, cells rewire their metabolism, switching from glucose-based metabolism to mitochondrial oxidation of fatty acids, which require the transfer of FAs from lipid droplets (LDs) to mitochondria at mitochondria−LD membrane contact sites (MCSs). However, factors responsible for FA transfer at these MCSs remain uncharacterized. Here, we demonstrate that vacuolar protein sorting-associated protein 13D (VPS13D), loss-of-function mutations of which cause spastic ataxia, coordinates FA trafficking in conjunction with the endosomal sorting complex required for transport (ESCRT) protein tumor susceptibility 101 (TSG101). The VPS13 adaptor-binding domain of VPS13D and TSG101 directly remodels LD membranes in a cooperative manner. The lipid transfer domain of human VPS13D binds glycerophospholipids and FAs in vitro. Depletion of VPS13D, TSG101, or ESCRT-III proteins inhibits FA trafficking from LDs to mitochondria. Our findings suggest that VPS13D mediates the ESCRT-dependent remodeling of LD membranes to facilitate FA transfer at mitochondria-LD contacts. Metabolic rewiring requires the mobilization of fatty acids (FA) from lipid droplets (LDs) at membrane contact sites (MCSs), although the details of FA transfer remain unclear. Here, the authors show that VPS13D and the ESCRT complex remodel LD membranes to promote FA trafficking to mitochondria.
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Affiliation(s)
- Jingru Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Na Fang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Juan Xiong
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yuanjiao Du
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yue Cao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wei-Ke Ji
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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86
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Wardaszka P, Soczewka P, Sienko M, Zoladek T, Kaminska J. Partial Inhibition of Calcineurin Activity by Rcn2 as a Potential Remedy for Vps13 Deficiency. Int J Mol Sci 2021; 22:ijms22031193. [PMID: 33530471 PMCID: PMC7865597 DOI: 10.3390/ijms22031193] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/12/2022] Open
Abstract
Regulation of calcineurin, a Ca2+/calmodulin-regulated phosphatase, is important for the nervous system, and its abnormal activity is associated with various pathologies, including neurodegenerative disorders. In yeast cells lacking the VPS13 gene (vps13Δ), a model of VPS13-linked neurological diseases, we recently demonstrated that calcineurin is activated, and its downregulation reduces the negative effects associated with vps13Δ mutation. Here, we show that overexpression of the RCN2 gene, which encodes a negative regulator of calcineurin, is beneficial for vps13Δ cells. We studied the molecular mechanism underlying this effect through site-directed mutagenesis of RCN2. The interaction of the resulting Rcn2 variants with a MAPK kinase, Slt2, and subunits of calcineurin was tested. We show that Rcn2 binds preferentially to Cmp2, one of two alternative catalytic subunits of calcineurin, and partially inhibits calcineurin. Rcn2 ability to bind to and reduce the activity of calcineurin was important for the suppression. The binding of Rcn2 to Cmp2 requires two motifs in Rcn2: the previously characterized C-terminal motif and a new N-terminal motif that was discovered in this study. Altogether, our findings can help to better understand calcineurin regulation and to develop new therapeutic strategies against neurodegenerative diseases based on modulation of the activity of selected calcineurin isoforms.
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87
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Ugur B, Hancock-Cerutti W, Leonzino M, De Camilli P. Role of VPS13, a protein with similarity to ATG2, in physiology and disease. Curr Opin Genet Dev 2020; 65:61-68. [PMID: 32563856 PMCID: PMC7746581 DOI: 10.1016/j.gde.2020.05.027] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 05/06/2020] [Accepted: 05/21/2020] [Indexed: 12/12/2022]
Abstract
The evolutionarily conserved VPS13 family proteins have been implicated in several cellular processes. Mutations in each of the four human VPS13s cause neurodevelopmental or neurodegenerative disorders. Until recently, the molecular function of VPS13 remained elusive. Genetic, functional and structural studies have now revealed that VPS13 acts at contact sites between intracellular organelles to transport lipids by a novel mechanism: direct transfer between bilayers via a hydrophobic channel that spans its entire rod-like N-terminal half. Predicted similarities to the autophagy protein ATG2 suggested a similar role for ATG2 that has now been confirmed by structural and functional studies. Here, after a brief review of this evidence, we discuss what is known of human VPS13 proteins in physiology and disease.
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Affiliation(s)
- Berrak Ugur
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - William Hancock-Cerutti
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Marianna Leonzino
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Howard Hughes Medical Institute, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, CT 06510, USA.
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88
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Faber AIE, van der Zwaag M, Schepers H, Eggens-Meijer E, Kanon B, IJsebaart C, Kuipers J, Giepmans BNG, Freire R, Grzeschik NA, Rabouille C, Sibon OCM. Vps13 is required for timely removal of nurse cell corpses. Development 2020; 147:dev.191759. [PMID: 32994170 DOI: 10.1242/dev.191759] [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: 04/20/2020] [Accepted: 09/15/2020] [Indexed: 12/25/2022]
Abstract
Programmed cell death and consecutive removal of cellular remnants is essential for development. During late stages of Drosophila melanogaster oogenesis, the small somatic follicle cells that surround the large nurse cells promote non-apoptotic nurse cell death, subsequently engulf them, and contribute to the timely removal of nurse cell corpses. Here, we identify a role for Vps13 in the timely removal of nurse cell corpses downstream of developmental programmed cell death. Vps13 is an evolutionarily conserved peripheral membrane protein associated with membrane contact sites and lipid transfer. It is expressed in late nurse cells, and persistent nurse cell remnants are observed when Vps13 is depleted from nurse cells but not from follicle cells. Microscopic analysis revealed enrichment of Vps13 in close proximity to the plasma membrane and the endoplasmic reticulum in nurse cells undergoing degradation. Ultrastructural analysis uncovered the presence of an underlying Vps13-dependent membranous structure in close association with the plasma membrane. The newly identified structure and function suggests the presence of a Vps13-dependent process required for complete degradation of bulky remnants of dying cells.
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Affiliation(s)
- Anita I E Faber
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Marianne van der Zwaag
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Hein Schepers
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Ellie Eggens-Meijer
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Bart Kanon
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Carmen IJsebaart
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Jeroen Kuipers
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Ben N G Giepmans
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Raimundo Freire
- Unidad de Investigación/FIISC, Hospital Universitario de Canarias, Ofra s/n, La Cuesta, 38320 San Cristóbal de La Laguna, Tenerife, Spain.,Instituto de Tecnologías Biomédicas, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Tenerife, Spain.,Facultad de Ciencias de la Salud, Universidad Fernando Pessoa Canarias, 35450 Las Palmas de Gran Canaria, Spain
| | - Nicola A Grzeschik
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
| | - Catherine Rabouille
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands.,Hubrecht Institute, University of Utrecht, 3584 CT, Utrecht, The Netherlands
| | - Ody C M Sibon
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, The University of Groningen, 9713 AV, Groningen, The Netherlands
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89
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The inner membrane protein YhdP modulates the rate of anterograde phospholipid flow in Escherichia coli. Proc Natl Acad Sci U S A 2020; 117:26907-26914. [PMID: 33046656 DOI: 10.1073/pnas.2015556117] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is a selective permeability barrier that allows uptake of nutrients while simultaneously protecting the cell from harmful compounds. The basic pathways and molecular machinery responsible for transporting lipopolysaccharides (LPS), lipoproteins, and β-barrel proteins to the OM have been identified, but very little is known about phospholipid (PL) transport. To identify genes capable of affecting PL transport, we screened for genetic interactions with mlaA*, a mutant in which anterograde PL transport causes the inner membrane (IM) to shrink and eventually rupture; characterization of mlaA*-mediated lysis suggested that PL transport can occur via a high-flux diffusive flow mechanism. We found that YhdP, an IM protein involved in maintaining the OM permeability barrier, modulates the rate of PL transport during mlaA*-mediated lysis. Deletion of yhdP from mlaA* reduced the rate of IM transport to the OM by 50%, slowing shrinkage of the IM and delaying lysis. As a result, the weakened OM of ∆yhdP cells was further compromised and ruptured before the IM during mlaA*-mediated death. These findings demonstrate the existence of a high-flux diffusive pathway for PL flow in Escherichia coli that is modulated by YhdP.
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90
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Vps13 is required for the packaging of the ER into autophagosomes during ER-phagy. Proc Natl Acad Sci U S A 2020; 117:18530-18539. [PMID: 32690699 DOI: 10.1073/pnas.2008923117] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Endoplasmic reticulum (ER) macroautophagy (hereafter called ER-phagy) uses autophagy receptors to selectively degrade ER domains in response to starvation or the accumulation of aggregation-prone proteins. Autophagy receptors package the ER into autophagosomes by binding to the ubiquitin-like yeast protein Atg8 (LC3 in mammals), which is needed for autophagosome formation. In budding yeast, cortical and cytoplasmic ER-phagy requires the autophagy receptor Atg40. While different ER autophagy receptors have been identified, little is known about other components of the ER-phagy machinery. In an effort to identify these components, we screened the genome-wide library of viable yeast deletion mutants for defects in the degradation of cortical ER following treatment with rapamycin, a drug that mimics starvation. Among the mutants we identified was vps13Δ. While yeast has one gene that encodes the phospholipid transporter VPS13, humans have four vacuolar protein-sorting (VPS) protein 13 isoforms. Mutations in all four human isoforms have been linked to different neurological disorders, including Parkinson's disease. Our findings have shown that Vps13 acts after Atg40 engages the autophagy machinery. Vps13 resides at contact sites between the ER and several organelles, including late endosomes. In the absence of Vps13, the cortical ER marker Rtn1 accumulated at late endosomes, and a dramatic decrease in ER packaging into autophagosomes was observed. Together, these studies suggest a role for Vps13 in the sequestration of the ER into autophagosomes at late endosomes. These observations may have important implications for understanding Parkinson's and other neurological diseases.
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Bohnert M. Tether Me, Tether Me Not—Dynamic Organelle Contact Sites in Metabolic Rewiring. Dev Cell 2020; 54:212-225. [DOI: 10.1016/j.devcel.2020.06.026] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/17/2020] [Accepted: 06/20/2020] [Indexed: 02/04/2023]
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Abstract
All lipid transport proteins in eukaryotes are thought to shuttle lipids between cellular membranes. In this issue, Li et al. (2020. J. Cell Biol.https://doi.org/10.1083/jcb.202001161) show that Vps13 has a channel-like domain that may allow lipids to flow between closely apposed membranes at contact sites.
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Affiliation(s)
- William A. Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - James H. Hurley
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA
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