1
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Zhang Y, Lin C. Lipid osmosis, membrane tension, and other mechanochemical driving forces of lipid flow. Curr Opin Cell Biol 2024; 88:102377. [PMID: 38823338 PMCID: PMC11193448 DOI: 10.1016/j.ceb.2024.102377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 05/12/2024] [Accepted: 05/13/2024] [Indexed: 06/03/2024]
Abstract
Nonvesicular lipid transport among different membranes or membrane domains plays crucial roles in lipid homeostasis and organelle biogenesis. However, the forces that drive such lipid transport are not well understood. We propose that lipids tend to flow towards the membrane area with a higher membrane protein density in a process termed lipid osmosis. This process lowers the membrane tension in the area, resulting in a membrane tension difference called osmotic membrane tension. We examine the thermodynamic basis and experimental evidence of lipid osmosis and osmotic membrane tension. We predict that lipid osmosis can drive bulk lipid flows between different membrane regions through lipid transfer proteins, scramblases, or similar barriers that selectively pass lipids but not membrane proteins. We also speculate on the biological functions of lipid osmosis. Finally, we explore other driving forces for lipid transfer and describe potential methods and systems to further test our theory.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA.
| | - Chenxiang Lin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA; Nanobiology Institute, Yale University, West Haven, CT 06516, USA; Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA.
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2
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John Peter AT, Kornmann B. Uncovering mechanisms of interorganelle lipid transport by enzymatic mass tagging. FEBS Lett 2024; 598:1292-1298. [PMID: 38268324 DOI: 10.1002/1873-3468.14810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 12/11/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024]
Abstract
Lipid trafficking is critical for the biogenesis and expansion of organelle membranes. Lipid transport proteins (LTPs) have been proposed to facilitate lipid transport at contact sites between organelles. Despite the fundamental importance of LTPs in cell physiology, our knowledge on the mechanisms of interorganelle lipid distribution remains poor due to the scarcity of assays to monitor lipid flux in vivo. In this review, we highlight the recent development of a versatile method named METALIC (Mass tagging-Enabled Tracking of Lipids in Cells), which uses a combination of enzymatic mass tagging and mass spectrometry to track lipid flux between organelles inside living cells. We discuss the methodology, its distinct advantages, limitations as well as its potential to unearth the pipelines of lipid transport and LTP function in vivo.
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3
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Enkler L, Spang A. Functional interplay of lipid droplets and mitochondria. FEBS Lett 2024; 598:1235-1251. [PMID: 38268392 DOI: 10.1002/1873-3468.14809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 12/12/2023] [Accepted: 01/04/2024] [Indexed: 01/26/2024]
Abstract
Our body stores energy mostly in form of fatty acids (FAs) in lipid droplets (LDs). From there the FAs can be mobilized and transferred to peroxisomes and mitochondria. This transfer is dependent on close opposition of LDs and mitochondria and peroxisomes and happens at membrane contact sites. However, the composition and the dynamics of these contact sites is not well understood, which is in part due to the dependence on the metabolic state of the cell and on the cell- and tissue-type. Here, we summarize the current knowledge on the contacts between lipid droplets and mitochondria both in mammals and in the yeast Saccharomyces cerevisiae, in which various contact sites are well studied. We discuss possible functions of the contact site and their implication in disease.
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Affiliation(s)
| | - Anne Spang
- Biozentrum, University of Basel, Switzerland
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4
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Dudka W, Salo VT, Mahamid J. Zooming into lipid droplet biology through the lens of electron microscopy. FEBS Lett 2024; 598:1127-1142. [PMID: 38726814 DOI: 10.1002/1873-3468.14899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 04/08/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Electron microscopy (EM), in its various flavors, has significantly contributed to our understanding of lipid droplets (LD) as central organelles in cellular metabolism. For example, EM has illuminated that LDs, in contrast to all other cellular organelles, are uniquely enclosed by a single phospholipid monolayer, revealed the architecture of LD contact sites with different organelles, and provided near-atomic resolution maps of key enzymes that regulate neutral lipid biosynthesis and LD biogenesis. In this review, we first provide a brief history of pivotal findings in LD biology unveiled through the lens of an electron microscope. We describe the main EM techniques used in the context of LD research and discuss their current capabilities and limitations, thereby providing a foundation for utilizing suitable EM methodology to address LD-related questions with sufficient level of structural preservation, detail, and resolution. Finally, we highlight examples where EM has recently been and is expected to be instrumental in expanding the frontiers of LD biology.
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Affiliation(s)
- Wioleta Dudka
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Veijo T Salo
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Julia Mahamid
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- Cell Biology and Biophysics Unit, EMBL, Heidelberg, Germany
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5
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Zhang Y, Lin C. Lipid osmosis, membrane tension, and other mechanochemical driving forces of lipid flow. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574656. [PMID: 38260424 PMCID: PMC10802412 DOI: 10.1101/2024.01.08.574656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Nonvesicular lipid transport among different membranes or membrane domains plays crucial roles in lipid homeostasis and organelle biogenesis. However, the forces that drive such lipid transport are not well understood. We propose that lipids tend to flow towards the membrane area with a higher membrane protein density in a process termed lipid osmosis. This process lowers the membrane tension in the area, resulting in a membrane tension difference called osmotic membrane tension. We examine the thermodynamic basis and experimental evidence of lipid osmosis and osmotic membrane tension. We predict that lipid osmosis can drive bulk lipid flows between different membrane regions through lipid transfer proteins, scramblases, or other similar barriers that selectively pass lipids but not membrane proteins. We also speculate on the biological functions of lipid osmosis. Finally, we explore other driving forces for lipid transfer and describe potential methods and systems to further test our theory.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA
| | - Chenxiang Lin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA
- Nanobiology Institute, Yale University, West Haven, CT 06516, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520, USA
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6
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Schmid M, Fischer P, Engl M, Widder J, Kerschbaum-Gruber S, Slade D. The interplay between autophagy and cGAS-STING signaling and its implications for cancer. Front Immunol 2024; 15:1356369. [PMID: 38660307 PMCID: PMC11039819 DOI: 10.3389/fimmu.2024.1356369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 03/26/2024] [Indexed: 04/26/2024] Open
Abstract
Autophagy is an intracellular process that targets various cargos for degradation, including members of the cGAS-STING signaling cascade. cGAS-STING senses cytosolic double-stranded DNA and triggers an innate immune response through type I interferons. Emerging evidence suggests that autophagy plays a crucial role in regulating and fine-tuning cGAS-STING signaling. Reciprocally, cGAS-STING pathway members can actively induce canonical as well as various non-canonical forms of autophagy, establishing a regulatory network of feedback mechanisms that alter both the cGAS-STING and the autophagic pathway. The crosstalk between autophagy and the cGAS-STING pathway impacts a wide variety of cellular processes such as protection against pathogenic infections as well as signaling in neurodegenerative disease, autoinflammatory disease and cancer. Here we provide a comprehensive overview of the mechanisms involved in autophagy and cGAS-STING signaling, with a specific focus on the interactions between the two pathways and their importance for cancer.
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Affiliation(s)
- Maximilian Schmid
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
| | - Patrick Fischer
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
| | - Magdalena Engl
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
- Vienna Biocenter PhD Program, a Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Joachim Widder
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
| | - Sylvia Kerschbaum-Gruber
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
| | - Dea Slade
- Department of Radiation Oncology, Medical University of Vienna, Vienna, Austria
- Comprehensive Cancer Center, Medical University of Vienna, Vienna, Austria
- MedAustron Ion Therapy Center, Wiener Neustadt, Austria
- Department of Medical Biochemistry, Medical University of Vienna, Max Perutz Labs, Vienna Biocenter, Vienna, Austria
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7
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Wang J, Xiong J, Zhang S, Li D, Chu Q, Chang W, Deng L, Ji WK. Biogenesis of Rab14-positive endosome buds at Golgi-endosome contacts by the RhoBTB3-SHIP164-Vps26B complex. Cell Discov 2024; 10:38. [PMID: 38565878 PMCID: PMC10987540 DOI: 10.1038/s41421-024-00651-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 01/25/2024] [Indexed: 04/04/2024] Open
Abstract
Early endosomes (EEs) are crucial in cargo sorting within vesicular trafficking. While cargoes destined for degradation are retained in EEs and eventually transported to lysosomes, recycled cargoes for the plasma membrane (PM) or the Golgi undergo segregation into specialized membrane structures known as EE buds during cargo sorting. Despite this significance, the molecular basis of the membrane expansion during EE bud formation has been poorly understood. In this study, we identify a protein complex comprising SHIP164, an ATPase RhoBTB3, and a retromer subunit Vps26B, which promotes the formation of EE buds at Golgi-EE contacts. Our findings reveal that Vps26B acts as a novel Rab14 effector, and Rab14 activity regulates the association of SHIP164 with EEs. Depletion of SHIP164 leads to enlarged Rab14+ EEs without buds, a phenotype rescued by wild-type SHIP164 but not the lipid transfer-defective mutants. Suppression of RhoBTB3 or Vps26B mirrors the effects of SHIP164 depletion. Together, we propose a lipid transport-dependent pathway mediated by the RhoBTB3-SHIP164-Vps26B complex at Golgi-EE contacts, which is essential for EE budding.
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Affiliation(s)
- Jingru Wang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
- Department of Ultrasound Medicine, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Juan Xiong
- Department of Anesthesiology and Pain Medicine, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, and Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Shuhan Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Dongchen Li
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
- Shenzhen Bay Laboratory, Shenzhen, Guangdong, China
| | - Qingzhu Chu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | | | - Lin Deng
- Shenzhen Bay Laboratory, Shenzhen, Guangdong, China.
| | - Wei-Ke Ji
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China.
- Shenzhen Bay Laboratory, Shenzhen, Guangdong, China.
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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8
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Suzuki SW, West M, Zhang Y, Fan JS, Roberts RT, Odorizzi G, Emr SD. A role for Vps13-mediated lipid transfer at the ER-endosome contact site in ESCRT-mediated sorting. J Cell Biol 2024; 223:e202307094. [PMID: 38319250 PMCID: PMC10847051 DOI: 10.1083/jcb.202307094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 12/27/2023] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
Endosomes are specialized organelles that function in the secretory and endocytic protein sorting pathways. Endocytosed cell surface receptors and transporters destined for lysosomal degradation are sorted into intraluminal vesicles (ILVs) at endosomes by endosomal sorting complexes required for transport (ESCRT) proteins. The endosomes (multivesicular bodies, MVBs) then fuse with the lysosome. During endosomal maturation, the number of ILVs increases, but the size of endosomes does not decrease despite the consumption of the limiting membrane during ILV formation. Vesicle-mediated trafficking is thought to provide lipids to support MVB biogenesis. However, we have uncovered an unexpected contribution of a large bridge-like lipid transfer protein, Vps13, in this process. Here, we reveal that Vps13-mediated lipid transfer at ER-endosome contact sites is required for the ESCRT pathway. We propose that Vps13 may play a critical role in supplying lipids to the endosome, ensuring continuous ESCRT-mediated sorting during MVB biogenesis.
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Affiliation(s)
- Sho W. Suzuki
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Matthew West
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Yichen Zhang
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Jenny S. Fan
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Rachel T. Roberts
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Greg Odorizzi
- Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, USA
| | - Scott D. Emr
- Weill Institute for Cell and Molecular Biology and Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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9
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Durant M, Mucelli X, Huang LS. Meiotic Cytokinesis in Saccharomyces cerevisiae: Spores That Just Need Closure. J Fungi (Basel) 2024; 10:132. [PMID: 38392804 PMCID: PMC10890087 DOI: 10.3390/jof10020132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, sporulation occurs during starvation of a diploid cell and results in the formation of four haploid spores forming within the mother cell ascus. Meiosis divides the genetic material that is encapsulated by the prospore membrane that grows to surround the haploid nuclei; this membrane will eventually become the plasma membrane of the haploid spore. Cellularization of the spores occurs when the prospore membrane closes to capture the haploid nucleus along with some cytoplasmic material from the mother cell, and thus, closure of the prospore membrane is the meiotic cytokinetic event. This cytokinetic event involves the removal of the leading-edge protein complex, a complex of proteins that localizes to the leading edge of the growing prospore membrane. The development and closure of the prospore membrane must be coordinated with other meiotic exit events such as spindle disassembly. Timing of the closure of the prospore membrane depends on the meiotic exit pathway, which utilizes Cdc15, a Hippo-like kinase, and Sps1, an STE20 family GCKIII kinase, acting in parallel to the E3 ligase Ama1-APC/C. This review describes the sporulation process and focuses on the development of the prospore membrane and the regulation of prospore membrane closure.
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Affiliation(s)
- Matthew Durant
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Xheni Mucelli
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Linda S Huang
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
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10
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Sun S, Zhao G, Jia M, Jiang Q, Li S, Wang H, Li W, Wang Y, Bian X, Zhao YG, Huang X, Yang G, Cai H, Pastor-Pareja JC, Ge L, Zhang C, Hu J. Stay in touch with the endoplasmic reticulum. SCIENCE CHINA. LIFE SCIENCES 2024; 67:230-257. [PMID: 38212460 DOI: 10.1007/s11427-023-2443-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 08/28/2023] [Indexed: 01/13/2024]
Abstract
The endoplasmic reticulum (ER), which is composed of a continuous network of tubules and sheets, forms the most widely distributed membrane system in eukaryotic cells. As a result, it engages a variety of organelles by establishing membrane contact sites (MCSs). These contacts regulate organelle positioning and remodeling, including fusion and fission, facilitate precise lipid exchange, and couple vital signaling events. Here, we systematically review recent advances and converging themes on ER-involved organellar contact. The molecular basis, cellular influence, and potential physiological functions for ER/nuclear envelope contacts with mitochondria, Golgi, endosomes, lysosomes, lipid droplets, autophagosomes, and plasma membrane are summarized.
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Affiliation(s)
- Sha Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Gan Zhao
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Mingkang Jia
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Jiang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Shulin Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Haibin Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenjing Li
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
| | - Yan G Zhao
- Brain Research Center, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Ge Yang
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Jose C Pastor-Pareja
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Institute of Neurosciences, Consejo Superior de Investigaciones Cientfflcas-Universidad Miguel Hernandez, San Juan de Alicante, 03550, Spain.
| | - Liang Ge
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Chuanmao Zhang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
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11
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Ronayne CT, Latorre-Muro P. Navigating the landscape of mitochondrial-ER communication in health and disease. Front Mol Biosci 2024; 11:1356500. [PMID: 38323074 PMCID: PMC10844478 DOI: 10.3389/fmolb.2024.1356500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/10/2024] [Indexed: 02/08/2024] Open
Abstract
Intracellular organelle communication enables the maintenance of tissue homeostasis and health through synchronized adaptive processes triggered by environmental cues. Mitochondrial-Endoplasmic Reticulum (ER) communication sustains cellular fitness by adjusting protein synthesis and degradation, and metabolite and protein trafficking through organelle membranes. Mitochondrial-ER communication is bidirectional and requires that the ER-components of the Integrated Stress Response signal to mitochondria upon activation and, likewise, mitochondria signal to the ER under conditions of metabolite and protein overload to maintain proper functionality and ensure cellular survival. Declines in the mitochondrial-ER communication occur upon ageing and correlate with the onset of a myriad of heterogeneous age-related diseases such as obesity, type 2 diabetes, cancer, or neurodegenerative pathologies. Thus, the exploration of the molecular mechanisms of mitochondrial-ER signaling and regulation will provide insights into the most fundamental cellular adaptive processes with important therapeutical opportunities. In this review, we will discuss the pathways and mechanisms of mitochondrial-ER communication at the mitochondrial-ER interface and their implications in health and disease.
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Affiliation(s)
- Conor T. Ronayne
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, United States
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States
| | - Pedro Latorre-Muro
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, United States
- Department of Cell Biology, Harvard Medical School, Boston, MA, United States
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12
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Voeltz GK, Sawyer EM, Hajnóczky G, Prinz WA. Making the connection: How membrane contact sites have changed our view of organelle biology. Cell 2024; 187:257-270. [PMID: 38242082 DOI: 10.1016/j.cell.2023.11.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 11/13/2023] [Accepted: 11/29/2023] [Indexed: 01/21/2024]
Abstract
The view of organelles and how they operate together has changed dramatically over the last two decades. The textbook view of organelles was that they operated largely independently and were connected by vesicular trafficking and the diffusion of signals through the cytoplasm. We now know that all organelles make functional close contacts with one another, often called membrane contact sites. The study of these sites has moved to center stage in cell biology as it has become clear that they play critical roles in healthy and developing cells and during cell stress and disease states. Contact sites have important roles in intracellular signaling, lipid metabolism, motor-protein-mediated membrane dynamics, organelle division, and organelle biogenesis. Here, we summarize the major conceptual changes that have occurred in cell biology as we have come to appreciate how contact sites integrate the activities of organelles.
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Affiliation(s)
- G K Voeltz
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
| | - E M Sawyer
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Boulder, CO 80309, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - G Hajnóczky
- MitoCare Center, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - W A Prinz
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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13
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Ching C, Maufront J, di Cicco A, Lévy D, Dezi M. C ool-contacts: Cryo-Electron Microscopy of Membrane Contact Sites and Their Components. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241231364. [PMID: 38410695 PMCID: PMC10895918 DOI: 10.1177/25152564241231364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 01/23/2024] [Indexed: 02/28/2024]
Abstract
Electron microscopy has played a pivotal role in elucidating the ultrastructure of membrane contact sites between cellular organelles. The advent of cryo-electron microscopy has ushered in the ability to determine atomic models of constituent proteins or protein complexes within sites of membrane contact through single particle analysis. Furthermore, it enables the visualization of the three-dimensional architecture of membrane contact sites, encompassing numerous copies of proteins, whether in vitro reconstituted or directly observed in situ using cryo-electron tomography. Nevertheless, there exists a scarcity of cryo-electron microscopy studies focused on the site of membrane contact and their constitutive proteins. This review provides an overview of the contributions made by cryo-electron microscopy to our understanding of membrane contact sites, outlines the associated limitations, and explores prospects in this field.
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Affiliation(s)
- Cyan Ching
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Julien Maufront
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Aurélie di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physique des Cellules et Cancer, Paris, France
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14
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Mann D, Fromm SA, Martinez-Sanchez A, Gopaldass N, Choy R, Mayer A, Sachse C. Atg18 oligomer organization in assembled tubes and on lipid membrane scaffolds. Nat Commun 2023; 14:8086. [PMID: 38057304 DOI: 10.1038/s41467-023-43460-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 11/09/2023] [Indexed: 12/08/2023] Open
Abstract
Autophagy-related protein 18 (Atg18) participates in the elongation of early autophagosomal structures in concert with Atg2 and Atg9 complexes. How Atg18 contributes to the structural coordination of Atg2 and Atg9 at the isolation membrane remains to be understood. Here, we determined the cryo-EM structures of Atg18 organized in helical tubes, Atg18 oligomers in solution as well as on lipid membrane scaffolds. The helical assembly is composed of Atg18 tetramers forming a lozenge cylindrical lattice with remarkable structural similarity to the COPII outer coat. When reconstituted with lipid membranes, using subtomogram averaging we determined tilted Atg18 dimer structures bridging two juxtaposed lipid membranes spaced apart by 80 Å. Moreover, lipid reconstitution experiments further delineate the contributions of Atg18's FRRG motif and the amphipathic helical extension in membrane interaction. The observed structural plasticity of Atg18's oligomeric organization and membrane binding properties provide a molecular framework for the positioning of downstream components of the autophagy machinery.
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Affiliation(s)
- Daniel Mann
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
| | - Simon A Fromm
- Structural and Computational Biology Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
- EMBL Imaging Centre, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Antonio Martinez-Sanchez
- Department of Information and Communications Engineering, Faculty of Computers Sciences, University of Murcia, Murcia, Spain
| | - Navin Gopaldass
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Ramona Choy
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
| | - Andreas Mayer
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - Carsten Sachse
- Ernst-Ruska Centre 3/Structural Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany.
- Institute for Biological Information Processing 6/Structural Cellular Biology, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany.
- Department of Biology, Heinrich Heine University, Universitätsstr. 1, Düsseldorf, Germany.
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15
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Shnaider TA, Khabarova AA, Morozova KN, Yunusova AM, Yakovleva SA, Chvileva AS, Wolf ER, Kiseleva EV, Grigor'eva EV, Voinova VY, Lagarkova MA, Pomerantseva EA, Musatova EV, Smirnov AV, Smirnova AV, Stoklitskaya DS, Arefieva TI, Larina DA, Nikitina TV, Pristyazhnyuk IE. Ultrastructural Abnormalities in Induced Pluripotent Stem Cell-Derived Neural Stem Cells and Neurons of Two Cohen Syndrome Patients. Cells 2023; 12:2702. [PMID: 38067130 PMCID: PMC10705360 DOI: 10.3390/cells12232702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/12/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Cohen syndrome is an autosomal recessive disorder caused by VPS13B (COH1) gene mutations. This syndrome is significantly underdiagnosed and is characterized by intellectual disability, microcephaly, autistic symptoms, hypotension, myopia, retinal dystrophy, neutropenia, and obesity. VPS13B regulates intracellular membrane transport and supports the Golgi apparatus structure, which is critical for neuron formation. We generated induced pluripotent stem cells from two patients with pronounced manifestations of Cohen syndrome and differentiated them into neural stem cells and neurons. Using transmission electron microscopy, we documented multiple new ultrastructural changes associated with Cohen syndrome in the neuronal cells. We discovered considerable disturbances in the structure of some organelles: Golgi apparatus fragmentation and swelling, endoplasmic reticulum structural reorganization, mitochondrial defects, and the accumulation of large autophagosomes with undigested contents. These abnormalities underline the ultrastructural similarity of Cohen syndrome to many neurodegenerative diseases. The cell models that we developed based on patient-specific induced pluripotent stem cells can serve to uncover not only neurodegenerative processes, but the causes of intellectual disability in general.
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Affiliation(s)
- Tatiana A Shnaider
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Anna A Khabarova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Ksenia N Morozova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Anastasia M Yunusova
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Sophia A Yakovleva
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Anastasia S Chvileva
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Ekaterina R Wolf
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk 630090, Russia
| | - Elena V Kiseleva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Elena V Grigor'eva
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Viktori Y Voinova
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
- The Mental Health Research Center, Moscow 115522, Russia
| | - Maria A Lagarkova
- Lopukhin Federal Research and Clinical Center of Physical-Chemical Medicine of Federal Medical Biological Agency, Moscow 119435, Russia
| | | | | | - Alexander V Smirnov
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Anna V Smirnova
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
| | | | - Tatiana I Arefieva
- National Medical Research Centre of Cardiology Named after Academician E. I. Chazov., Moscow 121552, Russia
| | - Daria A Larina
- Clinical Research Institute of Pediatrics Named after Acad. Y.E. Veltischev, Moscow 125412, Russia
| | - Tatiana V Nikitina
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk 634050, Russia
| | - Inna E Pristyazhnyuk
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia
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16
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Hanna M, Guillén-Samander A, De Camilli P. RBG Motif Bridge-Like Lipid Transport Proteins: Structure, Functions, and Open Questions. Annu Rev Cell Dev Biol 2023; 39:409-434. [PMID: 37406299 DOI: 10.1146/annurev-cellbio-120420-014634] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
The life of eukaryotic cells requires the transport of lipids between membranes, which are separated by the aqueous environment of the cytosol. Vesicle-mediated traffic along the secretory and endocytic pathways and lipid transfer proteins (LTPs) cooperate in this transport. Until recently, known LTPs were shown to carry one or a few lipids at a time and were thought to mediate transport by shuttle-like mechanisms. Over the last few years, a new family of LTPs has been discovered that is defined by a repeating β-groove (RBG) rod-like structure with a hydrophobic channel running along their entire length. This structure and the localization of these proteins at membrane contact sites suggest a bridge-like mechanism of lipid transport. Mutations in some of these proteins result in neurodegenerative and developmental disorders. Here we review the known properties and well-established or putative physiological roles of these proteins, and we highlight the many questions that remain open about their functions.
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Affiliation(s)
- Michael Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Andrés Guillén-Samander
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut, USA;
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut, USA
- Aligning Science Across Parkinson's Collaborative Research Network, Chevy Chase, Maryland, USA
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17
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Cooper BF, Clark R, Kudhail A, Bhabha G, Ekiert DC, Khalid S, Isom GL. Phospholipid transport to the bacterial outer membrane through an envelope-spanning bridge. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.05.561070. [PMID: 37873249 PMCID: PMC10592960 DOI: 10.1101/2023.10.05.561070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
The outer membrane of Gram-negative bacteria provides a formidable barrier, essential for both pathogenesis and antimicrobial resistance. Biogenesis of the outer membrane requires the transport of phospholipids across the cell envelope. Recently, YhdP was implicated as a major protagonist in the transport of phospholipids from the inner membrane to the outer membrane however the molecular mechanism of YhdP mediated transport remains elusive. Here, utilising AlphaFold, we observe YhdP to form an elongated assembly of 60 β strands that curve to form a continuous hydrophobic groove. This architecture is consistent with our negative stain electron microscopy data which reveals YhdP to be approximately 250 Å in length and thus sufficient to span the bacterial cell envelope. Furthermore, molecular dynamics simulations and in vivo bacterial growth assays indicate essential helical regions at the N- and C-termini of YhdP, that may embed into the inner and outer membranes respectively, reinforcing its envelope spanning nature. Our in vivo crosslinking data reveal phosphate-containing substrates captured along the length of the YhdP groove, providing direct evidence that YhdP transports phospholipids. This finding is congruent with our molecular dynamics simulations which demonstrate the propensity for inner membrane lipids to spontaneously enter the groove of YhdP. Collectively, our results support a model in which YhdP bridges the cell envelope, providing a hydrophobic environment for the transport of phospholipids to the outer membrane.
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Affiliation(s)
- Benjamin F. Cooper
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Robert Clark
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Anju Kudhail
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016
| | - Damian C. Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, NY, 10016
- Department of Microbiology, New York University School of Medicine, New York, NY, 10016
| | - Syma Khalid
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Georgia L. Isom
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
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18
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Korfhage JL, Wan N, Elhan H, Kauffman L, Pineda M, Fuller DM, Thiam AR, Reinisch KM, Melia TJ. ATG2A-mediated bridge-like lipid transport regulates lipid droplet accumulation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.14.553257. [PMID: 37645754 PMCID: PMC10461963 DOI: 10.1101/2023.08.14.553257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
ATG2 proteins facilitate bulk lipid transport between membranes. ATG2 is an essential autophagy protein, but ATG2 also localizes to lipid droplets (LDs), and genetic depletion of ATG2 increases LD numbers while impairing fatty acid transport from LDs to mitochondria. How ATG2 supports LD homeostasis and whether lipid transport regulates this homeostasis remains unknown. Here we demonstrate that ATG2 is preferentially recruited to phospholipid monolayers such as those surrounding LDs rather than to phospholipid bilayers. In vitro, ATG2 can drive phospholipid transport from artificial LDs with rates that correlate with the binding affinities, such that phospholipids are moved much more efficiently when one of the ATG2-interacting structures is an artificial LD. ATG2 is thought to exhibit 'bridge-like" lipid transport, with lipids flowing across the protein between membranes. We mutated key amino acids within the bridge to form a transport-dead ATG2 mutant (TD-ATG2A) which we show specifically blocks bridge-like, but not shuttle-like, lipid transport in vitro. TD-ATG2A still localizes to LDs, but is unable to rescue LD accumulation in ATG2 knockout cells. Thus, ATG2 has a natural affinity for, and an enhanced activity upon LD surfaces and uses bridge-like lipid transport to support LD dynamics in cells.
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Affiliation(s)
- Justin L. Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Helin Elhan
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Lisa Kauffman
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Mia Pineda
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Devin M. Fuller
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, 75005 Paris, France
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510
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19
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Dabrowski R, Tulli S, Graef M. Parallel phospholipid transfer by Vps13 and Atg2 determines autophagosome biogenesis dynamics. J Cell Biol 2023; 222:e202211039. [PMID: 37115156 PMCID: PMC10148235 DOI: 10.1083/jcb.202211039] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 03/30/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
During autophagy, rapid membrane assembly expands small phagophores into large double-membrane autophagosomes. Theoretical modeling predicts that the majority of autophagosomal phospholipids are derived from highly efficient non-vesicular phospholipid transfer (PLT) across phagophore-ER contacts (PERCS). Currently, the phagophore-ER tether Atg2 is the only PLT protein known to drive phagophore expansion in vivo. Here, our quantitative live-cell imaging analysis reveals a poor correlation between the duration and size of forming autophagosomes and the number of Atg2 molecules at PERCS of starving yeast cells. Strikingly, we find that Atg2-mediated PLT is non-rate limiting for autophagosome biogenesis because membrane tether and the PLT protein Vps13 localizes to the rim and promotes the expansion of phagophores in parallel with Atg2. In the absence of Vps13, the number of Atg2 molecules at PERCS determines the duration and size of forming autophagosomes with an apparent in vivo transfer rate of ∼200 phospholipids per Atg2 molecule and second. We propose that conserved PLT proteins cooperate in channeling phospholipids across organelle contact sites for non-rate-limiting membrane assembly during autophagosome biogenesis.
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Affiliation(s)
- Rahel Dabrowski
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Susanna Tulli
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Martin Graef
- Max Planck Research Group of Autophagy and Cellular Ageing, Max Planck Institute for Biology of Ageing, Cologne, Germany
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
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20
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Tornero-Écija A, Zapata-Del-Baño A, Antón-Esteban L, Vincent O, Escalante R. The association of lipid transfer protein VPS13A with endosomes is mediated by sorting nexin SNX5. Life Sci Alliance 2023; 6:e202201852. [PMID: 36977596 PMCID: PMC10053439 DOI: 10.26508/lsa.202201852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 03/17/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Human VPS13 proteins are implicated in severe neurological diseases. These proteins play an important role in lipid transport at membrane contact sites between different organelles. Identification of adaptors that regulate the subcellular localization of these proteins at specific membrane contact sites is essential to understand their function and role in disease. We have identified the sorting nexin SNX5 as an interactor of VPS13A that mediates its association with endosomal subdomains. As for the yeast sorting nexin and Vps13 endosomal adaptor Ypt35, this association involves the VPS13 adaptor-binding (VAB) domain in VPS13A and a PxP motif in SNX5. Notably, this interaction is impaired by mutation of a conserved asparagine residue in the VAB domain, which is also required for Vps13-adaptor binding in yeast and is pathogenic in VPS13D. VPS13A fragments containing the VAB domain co-localize with SNX5, whereas the more C-terminal part of VPS13A directs its localization to the mitochondria. Overall, our results suggest that a fraction of VPS13A localizes to junctions between the endoplasmic reticulum, mitochondria, and SNX5-containing endosomes.
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Affiliation(s)
- Alba Tornero-Écija
- Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C./U.A.M., Madrid, Spain
| | | | - Laura Antón-Esteban
- Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C./U.A.M., Madrid, Spain
| | - Olivier Vincent
- Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C./U.A.M., Madrid, Spain
| | - Ricardo Escalante
- Instituto de Investigaciones Biomédicas Alberto Sols, C.S.I.C./U.A.M., Madrid, Spain
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21
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Henne WM. The (social) lives, deaths, and biophysical phases of lipid droplets. Curr Opin Cell Biol 2023; 82:102178. [PMID: 37295067 PMCID: PMC10782554 DOI: 10.1016/j.ceb.2023.102178] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023]
Abstract
Lipid droplets (LDs) are major lipid storage organelles, sequestering energy-rich triglycerides and serving as nutrient sinks for cellular homeostasis. Observed for over a century but generally ignored, LDs are now appreciated to play key roles in organismal physiology and disease. They also form numerous functional contacts with other organelles. Here, we highlight recent studies examining LDs from distinct perspectives of their life cycle: their biogenesis, "social" life as they interact with other organelles, and deaths via lipolysis or lipophagy. We also discuss recent work showing how changes in LD lipid content alter the biophysical phases of LD lipids, and how this may fine-tune the LD protein landscape and ultimately LD function.
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Affiliation(s)
- W Mike Henne
- Department of Cell Biology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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22
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Wozny MR, Di Luca A, Morado DR, Picco A, Khaddaj R, Campomanes P, Ivanović L, Hoffmann PC, Miller EA, Vanni S, Kukulski W. In situ architecture of the ER-mitochondria encounter structure. Nature 2023:10.1038/s41586-023-06050-3. [PMID: 37165187 DOI: 10.1038/s41586-023-06050-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 04/04/2023] [Indexed: 05/12/2023]
Abstract
The endoplasmic reticulum and mitochondria are main hubs of eukaryotic membrane biogenesis that rely on lipid exchange via membrane contact sites1-3, but the underpinning mechanisms remain poorly understood. In yeast, tethering and lipid transfer between the two organelles is mediated by the endoplasmic reticulum-mitochondria encounter structure (ERMES), a four-subunit complex of unresolved stoichiometry and architecture4-6. Here we determined the molecular organization of ERMES within Saccharomyces cerevisiae cells using integrative structural biology by combining quantitative live imaging, cryo-correlative microscopy, subtomogram averaging and molecular modelling. We found that ERMES assembles into approximately 25 discrete bridge-like complexes distributed irregularly across a contact site. Each bridge consists of three synaptotagmin-like mitochondrial lipid binding protein domains oriented in a zig-zag arrangement. Our molecular model of ERMES reveals a pathway for lipids. These findings resolve the in situ supramolecular architecture of a major inter-organelle lipid transfer machinery and provide a basis for the mechanistic understanding of lipid fluxes in eukaryotic cells.
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Affiliation(s)
- Michael R Wozny
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
| | - Andrea Di Luca
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Dustin R Morado
- MRC Laboratory of Molecular Biology, Cambridge, UK
- SciLifeLab, Solna, Sweden
- Max Planck Institute of Biochemistry, Martinsried, Germany
| | - Andrea Picco
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Rasha Khaddaj
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Lazar Ivanović
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Patrick C Hoffmann
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany
| | | | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland.
| | - Wanda Kukulski
- MRC Laboratory of Molecular Biology, Cambridge, UK.
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland.
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23
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Guillén-Samander A, De Camilli P. Endoplasmic Reticulum Membrane Contact Sites, Lipid Transport, and Neurodegeneration. Cold Spring Harb Perspect Biol 2023; 15:a041257. [PMID: 36123033 PMCID: PMC10071438 DOI: 10.1101/cshperspect.a041257] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Endoplasmic Reticulum (ER) is an endomembrane system that plays a multiplicity of roles in cell physiology and populates even the most distal cell compartments, including dendritic tips and axon terminals of neurons. Some of its functions are achieved by a cross talk with other intracellular membranous organelles and with the plasma membrane at membrane contacts sites (MCSs). As the ER synthesizes most membrane lipids, lipid exchanges mediated by lipid transfer proteins at MCSs are a particularly important aspect of this cross talk, which synergizes with the cross talk mediated by vesicular transport. Several mutations of genes that encode proteins localized at ER MCSs result in familial neurodegenerative diseases, emphasizing the importance of the normal lipid traffic within cells for a healthy brain. Here, we provide an overview of such diseases, with a specific focus on proteins that directly or indirectly impact lipid transport.
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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, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
| | - 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, Connecticut 06520, USA
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, Maryland 20815, USA
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24
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Dall'Armellina F, Stagi M, Swan LE. In silico modeling human VPS13 proteins associated with donor and target membranes suggests lipid transfer mechanisms. Proteins 2023; 91:439-455. [PMID: 36404287 PMCID: PMC10953354 DOI: 10.1002/prot.26446] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 10/14/2022] [Accepted: 11/03/2022] [Indexed: 11/22/2022]
Abstract
The VPS13 protein family constitutes a novel class of bridge-like lipid transferases. Autosomal recessive inheritance of mutations in VPS13 genes is associated with the development of neurodegenerative diseases in humans. Bioinformatic approaches previously recognized the domain architecture of these proteins. In this study, we model the first ever full-length structures of the four human homologs VPS13A, VPS13B, VPS13C, and VPS13D in association with model membranes, to investigate their lipid transfer ability and potential structural association with membrane leaflets. We analyze the evolutionary conservation and physicochemical properties of these proteins, focusing on conserved C-terminal amphipathic helices that disturb organelle surfaces and that, adjoined, resemble a traditional Venetian gondola. The gondola domains share significant structural homology with lipid droplet surface-binding proteins. We introduce in silico protein-membrane models displaying the mode of association of VPS13A, VPS13B, VPS13C, and VPS13D to donor and target membranes, and present potential models of action for protein-mediated lipid transfer.
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Affiliation(s)
- Filippo Dall'Armellina
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Massimiliano Stagi
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
| | - Laura E. Swan
- Department of Biochemistry and Systems BiologyInstitute of Systems, Molecular and Integrative Biology, University of LiverpoolLiverpoolUK
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25
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Cai W, Li P, Gu M, Xu H. Lysosomal Ion Channels and Lysosome-Organelle Interactions. Handb Exp Pharmacol 2023; 278:93-108. [PMID: 36882602 DOI: 10.1007/164_2023_640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Intracellular organelles exchange their luminal contents with each other via both vesicular and non-vesicular mechanisms. By forming membrane contact sites (MCSs) with ER and mitochondria, lysosomes mediate bidirectional transport of metabolites and ions between lysosomes and organelles that regulate lysosomal physiology, movement, membrane remodeling, and membrane repair. In this chapter, we will first summarize the current knowledge of lysosomal ion channels and then discuss the molecular and physiological mechanisms that regulate lysosome-organelle MCS formation and dynamics. We will also discuss the roles of lysosome-ER and lysosome-mitochondria MCSs in signal transduction, lipid transport, Ca 2+ transfer, membrane trafficking, and membrane repair, as well as their roles in lysosome-related pathologies.
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Affiliation(s)
- Weijie Cai
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Ping Li
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China
| | - Mingxue Gu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dun Neurological Research Institute, Houston, TX, USA
| | - Haoxing Xu
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou, China. .,Department of Molecular and Human Genetics, Baylor College of Medicine, Jan and Dun Neurological Research Institute, Houston, TX, USA. .,Department of Neurology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China. .,Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China.
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26
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Du Y, Chang W, Gao L, Deng L, Ji WK. Tex2 is required for lysosomal functions at TMEM55-dependent ER membrane contact sites. J Cell Biol 2023; 222:213838. [PMID: 36705603 PMCID: PMC9930140 DOI: 10.1083/jcb.202205133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 10/17/2022] [Accepted: 01/05/2023] [Indexed: 01/28/2023] Open
Abstract
ER tubules form and maintain membrane contact sites (MCSs) with late endosomes/lysosomes (LE/lys). The molecular composition and cellular functions of these MCSs are poorly understood. Here, we find that Tex2, an SMP domain-containing lipid transfer protein conserved in metazoan and yeast, is a tubular ER protein and is recruited to ER-LE/lys MCSs by TMEM55, phosphatases that convert PI(4,5)P2 to PI5P on LE/lys. We show that the Tex2-TMEM55 interaction occurs between an N-terminal region of Tex2 and a catalytic motif in the PTase domain of TMEM55. The Tex2-TMEM55 interaction can be regulated by endosome-resident type 2 PI4K activities. Functionally, Tex2 knockout results in defects in lysosomal trafficking, digestive capacity, and lipid composition of LE/lys membranes. Together, our data identify Tex2 as a tubular ER protein that resides at TMEM55-dependent ER-LE/lys MCSs required for lysosomal functions.
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Affiliation(s)
- Yuanjiao Du
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Wuhan, China,https://ror.org/00p991c53Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China,https://ror.org/00sdcjz77Shenzhen Bay Laboratory, Shenzhen, China
| | - Weiping Chang
- https://ror.org/00sdcjz77Shenzhen Bay Laboratory, Shenzhen, China
| | - Lei Gao
- https://ror.org/05hfa4n20Microscopy Core Facility, Westlake University, Hangzhou, Zhejiang, China
| | - Lin Deng
- https://ror.org/00sdcjz77Shenzhen Bay Laboratory, Shenzhen, China
| | - Wei-Ke Ji
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Tongji Medical College, Wuhan, China,https://ror.org/00p991c53Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, Hubei, China,https://ror.org/00sdcjz77Shenzhen Bay Laboratory, Shenzhen, China,Correspondence to Wei-Ke Ji:
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27
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Subra M, Dezi M, Bigay J, Lacas-Gervais S, Di Cicco A, Araújo ARD, Abélanet S, Fleuriot L, Debayle D, Gautier R, Patel A, Roussi F, Antonny B, Lévy D, Mesmin B. VAP-A intrinsically disordered regions enable versatile tethering at membrane contact sites. Dev Cell 2023; 58:121-138.e9. [PMID: 36693319 DOI: 10.1016/j.devcel.2022.12.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 10/21/2022] [Accepted: 12/20/2022] [Indexed: 01/24/2023]
Abstract
Membrane contact sites (MCSs) are heterogeneous in shape, composition, and dynamics. Despite this diversity, VAP proteins act as receptors for multiple FFAT motif-containing proteins and drive the formation of most MCSs that involve the endoplasmic reticulum (ER). Although the VAP-FFAT interaction is well characterized, no model explains how VAP adapts to its partners in various MCSs. We report that VAP-A localization to different MCSs depends on its intrinsically disordered regions (IDRs) in human cells. VAP-A interaction with PTPIP51 and VPS13A at ER-mitochondria MCS conditions mitochondria fusion by promoting lipid transfer and cardiolipin buildup. VAP-A also enables lipid exchange at ER-Golgi MCS by interacting with oxysterol-binding protein (OSBP) and CERT. However, removing IDRs from VAP-A restricts its distribution and function to ER-mitochondria MCS. Our data suggest that IDRs do not modulate VAP-A preference toward specific partners but do adjust their geometry to MCS organization and lifetime constraints. Thus, IDR-mediated VAP-A conformational flexibility ensures membrane tethering plasticity and efficiency.
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Affiliation(s)
- Mélody Subra
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Manuela Dezi
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Joëlle Bigay
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sandra Lacas-Gervais
- Université Côte d'Azur, Centre Commun de Microscopie Appliquée, Parc Valrose, 06000 Nice, France
| | - Aurélie Di Cicco
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Ana Rita Dias Araújo
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Sophie Abélanet
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Lucile Fleuriot
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Delphine Debayle
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Romain Gautier
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Amanda Patel
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Fanny Roussi
- Institut de Chimie des Substances Naturelles, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Bruno Antonny
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France
| | - Daniel Lévy
- Institut Curie, Université PSL, Sorbonne Université, CNRS UMR168, Laboratoire Physico-Chimie Curie, 75005 Paris, France
| | - Bruno Mesmin
- Université Côte d'Azur, Inserm, CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
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28
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Braschi B, Bruford EA, Cavanagh AT, Neuman SD, Bashirullah A. The bridge-like lipid transfer protein (BLTP) gene group: introducing new nomenclature based on structural homology indicating shared function. Hum Genomics 2022; 16:66. [PMID: 36461115 PMCID: PMC9719229 DOI: 10.1186/s40246-022-00439-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/22/2022] [Indexed: 12/03/2022] Open
Abstract
The HUGO Gene Nomenclature Committee assigns unique symbols and names to human genes. The use of approved nomenclature enables effective communication between researchers, and there are multiple examples of how the usage of unapproved alias symbols can lead to confusion. We discuss here a recent nomenclature update (May 2022) for a set of genes that encode proteins with a shared repeating β-groove domain. Some of the proteins encoded by genes in this group have already been shown to function as lipid transporters. By working with researchers in the field, we have been able to introduce a new root symbol (BLTP, which stands for "bridge-like lipid transfer protein") for this domain-based gene group. This new nomenclature not only reflects the shared domain in these proteins, but also takes into consideration the mounting evidence of a shared lipid transport function.
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Affiliation(s)
- Bryony Braschi
- grid.225360.00000 0000 9709 7726HUGO Gene Nomenclature Committee, European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridgeshire, CB10 1SD UK
| | - Elspeth A. Bruford
- grid.225360.00000 0000 9709 7726HUGO Gene Nomenclature Committee, European Molecular Biology Laboratory, European Bioinformatics Institute, Hinxton, Cambridgeshire, CB10 1SD UK ,grid.5335.00000000121885934Department of Haematology, School of Clinical Medicine, University of Cambridge, Cambridge, Cambridgeshire, CB2 0AW UK
| | - Amy T. Cavanagh
- grid.14003.360000 0001 2167 3675Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222 USA
| | - Sarah D. Neuman
- grid.14003.360000 0001 2167 3675Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222 USA
| | - Arash Bashirullah
- grid.14003.360000 0001 2167 3675Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222 USA
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29
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Weng X, Wang H. Apical vesicles: Social networking at the pollen tube tip. REPRODUCTION AND BREEDING 2022. [DOI: 10.1016/j.repbre.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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30
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Castro IG, Shortill SP, Dziurdzik SK, Cadou A, Ganesan S, Valenti R, David Y, Davey M, Mattes C, Thomas FB, Avraham RE, Meyer H, Fadel A, Fenech EJ, Ernst R, Zaremberg V, Levine TP, Stefan C, Conibear E, Schuldiner M. Systematic analysis of membrane contact sites in Saccharomyces cerevisiae uncovers modulators of cellular lipid distribution. eLife 2022; 11:74602. [DOI: 10.7554/elife.74602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
Actively maintained close appositions between organelle membranes, also known as contact sites, enable the efficient transfer of biomolecules between cellular compartments. Several such sites have been described as well as their tethering machineries. Despite these advances we are still far from a comprehensive understanding of the function and regulation of most contact sites. To systematically characterize contact site proteomes, we established a high-throughput screening approach in Saccharomyces cerevisiae based on co-localization imaging. We imaged split fluorescence reporters for six different contact sites, several of which are poorly characterized, on the background of 1165 strains expressing a mCherry-tagged yeast protein that has a cellular punctate distribution (a hallmark of contact sites), under regulation of the strong TEF2 promoter. By scoring both co-localization events and effects on reporter size and abundance, we discovered over 100 new potential contact site residents and effectors in yeast. Focusing on several of the newly identified residents, we identified three homologs of Vps13 and Atg2 that are residents of multiple contact sites. These proteins share their lipid transport domain, thus expanding this family of lipid transporters. Analysis of another candidate, Ypr097w, which we now call Lec1 (Lipid-droplet Ergosterol Cortex 1), revealed that this previously uncharacterized protein dynamically shifts between lipid droplets and the cell cortex, and plays a role in regulation of ergosterol distribution in the cell. Overall, our analysis expands the universe of contact site residents and effectors and creates a rich database to mine for new functions, tethers, and regulators.
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Affiliation(s)
| | - Shawn P Shortill
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Samantha Katarzyna Dziurdzik
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Angela Cadou
- Laboratory for Molecular Cell Biology, University College London
| | | | - Rosario Valenti
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Yotam David
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
| | - Carsten Mattes
- Medical Biochemistry and Molecular Biology, PZMS, Medical Faculty, Saarland University
| | - Ffion B Thomas
- Laboratory for Molecular Cell Biology, University College London
| | | | - Hadar Meyer
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Amir Fadel
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Emma J Fenech
- Department of Molecular Genetics, Weizmann Institute of Science
| | - Robert Ernst
- Medical Biochemistry and Molecular Biology, PZMS, Medical Faculty, Saarland University
| | | | - Tim P Levine
- UCL Institute of Ophthalmology, University College London
| | | | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, British Columbia Children’s Hospital Research Institute, University of British Columbia
- Department of Medical Genetics, University of British Columbia
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science
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31
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McEwan DG, Ryan KM. ATG2 and VPS13 proteins: molecular highways transporting lipids to drive membrane expansion and organelle communication. FEBS J 2022; 289:7113-7127. [PMID: 34783437 DOI: 10.1111/febs.16280] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/03/2021] [Accepted: 11/15/2021] [Indexed: 01/13/2023]
Abstract
Communication between organelles is an essential process that helps maintain cellular homeostasis and organelle contact sites have recently emerged as crucial mediators of this communication. The emergence of a class of molecular bridges that span the inter-organelle gaps has now been shown to direct the flow of lipid traffic from one lipid bilayer to another. One of the key components of these molecular bridges is the presence of an N-terminal Chorein/VPS13 domain. This is an evolutionarily conserved domain present in multiple proteins within the endocytic and autophagy trafficking pathways. Herein, we discuss the current state-of-the-art of this class of proteins, focusing on the role of these lipid transporters in the autophagy and endocytic pathways. We discuss the recent biochemical and structural advances that have highlighted the essential role Chorein-N domain containing ATG2 proteins play in driving the formation of the autophagosome and how lipids are transported from the endoplasmic reticulum to the growing phagophore. We also consider the VPS13 proteins, their role in organelle contacts and the endocytic pathway and highlight how disease-causing mutations disrupt these contact sites. Finally, we open the door to discuss other Chorein_N domain containing proteins, for instance, UHRF1BP1/1L, their role in disease and look towards prokaryote examples of Chorein_N-like domains. Taken together, recent advances have highlighted an exciting opportunity to delve deeper into inter-organelle communication and understand how lipids are transported between membrane bilayers and how this process is disrupted in multiple diseases.
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Affiliation(s)
| | - Kevin M Ryan
- Cancer Research UK Beatson Institute, Glasgow, UK
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK
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32
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Fujiki Y, Okumoto K, Honsho M, Abe Y. Molecular insights into peroxisome homeostasis and peroxisome biogenesis disorders. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119330. [PMID: 35917894 DOI: 10.1016/j.bbamcr.2022.119330] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
Peroxisomes are single-membrane organelles essential for cell metabolism including the β-oxidation of fatty acids, synthesis of etherlipid plasmalogens, and redox homeostasis. Investigations into peroxisome biogenesis and the human peroxisome biogenesis disorders (PBDs) have identified 14 PEX genes encoding peroxins involved in peroxisome biogenesis and the mutation of PEX genes is responsible for the PBDs. Many recent findings have further advanced our understanding of the biology, physiology, and consequences of a functional deficit of peroxisomes. In this Review, we discuss cell defense mechanisms that counteract oxidative stress by 1) a proapoptotic Bcl-2 factor BAK-mediated release to the cytosol of H2O2-degrading catalase from peroxisomes and 2) peroxisomal import suppression of catalase by Ser232-phosphorylation of Pex14, a docking protein for the Pex5-PTS1 complex. With respect to peroxisome division, the important issue of how the energy-rich GTP is produced and supplied for the division process was recently addressed by the discovery of a nucleoside diphosphate kinase-like protein, termed DYNAMO1 in a lower eukaryote, which has a mammalian homologue NME3. In regard to the mechanisms underlying the pathogenesis of PBDs, a new PBD model mouse defective in Pex14 manifests a dysregulated brain-derived neurotrophic factor (BDNF)-TrkB pathway, an important signaling pathway for cerebellar morphogenesis. Communications between peroxisomes and other organelles are also addressed.
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Affiliation(s)
- Yukio Fujiki
- Medical Institute of Bioregulation, Institute of Rheological Functions of Food, Collaboration Program, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan.
| | - Kanji Okumoto
- Department of Biology and Graduate School of Systems Life Sciences, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
| | - Masanori Honsho
- Medical Institute of Bioregulation, Institute of Rheological Functions of Food, Collaboration Program, Kyushu University, 3-1-1 Maidashi, Fukuoka 812-8582, Japan
| | - Yuichi Abe
- Faculty of Arts and Science, Kyushu University, 744 Motooka, Fukuoka 819-0395, Japan
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33
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Neuman SD, Levine TP, Bashirullah A. A novel superfamily of bridge-like lipid transfer proteins. Trends Cell Biol 2022; 32:962-974. [PMID: 35491307 PMCID: PMC9588498 DOI: 10.1016/j.tcb.2022.03.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/28/2022] [Accepted: 03/30/2022] [Indexed: 01/21/2023]
Abstract
Lipid transfer proteins mediate nonvesicular transport of lipids at membrane contact sites to regulate the lipid composition of organelle membranes. Recently, a new type of bridge-like lipid transfer protein has emerged; these proteins contain a long hydrophobic groove and can mediate bulk transport of lipids between organelles. Here, we review recent insights into the structure of these proteins and identify a repeating modular unit that we propose to name the repeating β-groove (RBG) domain. This new structural understanding conceptually unifies all the RBG domain-containing lipid transfer proteins as members of an RBG protein superfamily. We also examine the biological functions of these lipid transporters in normal physiology and disease and speculate on the evolutionary origins of RBG proteins in bacteria.
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Affiliation(s)
- Sarah D Neuman
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA
| | - Tim P Levine
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
| | - Arash Bashirullah
- Division of Pharmaceutical Sciences, University of Wisconsin-Madison, Madison, WI 53705-2222, USA.
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34
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Giacometti SI, MacRae MR, Dancel-Manning K, Bhabha G, Ekiert DC. Lipid Transport Across Bacterial Membranes. Annu Rev Cell Dev Biol 2022; 38:125-153. [PMID: 35850151 DOI: 10.1146/annurev-cellbio-120420-022914] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The movement of lipids within and between membranes in bacteria is essential for building and maintaining the bacterial cell envelope. Moving lipids to their final destination is often energetically unfavorable and does not readily occur spontaneously. Bacteria have evolved several protein-mediated transport systems that bind specific lipid substrates and catalyze the transport of lipids across membranes and from one membrane to another. Specific protein flippases act in translocating lipids across the plasma membrane, overcoming the obstacle of moving relatively large and chemically diverse lipids between leaflets of the bilayer. Active transporters found in double-membraned bacteria have evolved sophisticated mechanisms to traffic lipids between the two membranes, including assembling to form large, multiprotein complexes that resemble bridges, shuttles, and tunnels, shielding lipids from the hydrophilic environment of the periplasm during transport. In this review, we explore our current understanding of the mechanisms thought to drive bacterial lipid transport.
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Affiliation(s)
- Sabrina I Giacometti
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Mark R MacRae
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Kristen Dancel-Manning
- Office of Science and Research, New York University School of Medicine, New York, NY, USA;
| | - Gira Bhabha
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
| | - Damian C Ekiert
- Department of Cell Biology, New York University School of Medicine, New York, NY, USA; , , ,
- Department of Microbiology, New York University School of Medicine, New York, NY, USA
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35
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Zhang Y, Ge J, Bian X, Kumar A. Quantitative Models of Lipid Transfer and Membrane Contact Formation. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:1-21. [PMID: 36120532 DOI: 10.1177/25152564221096024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lipid transfer proteins (LTPs) transfer lipids between different organelles, and thus play key roles in lipid homeostasis and organelle dynamics. The lipid transfer often occurs at the membrane contact sites (MCS) where two membranes are held within 10-30 nm. While most LTPs act as a shuttle to transfer lipids, recent experiments reveal a new category of eukaryotic LTPs that may serve as a bridge to transport lipids in bulk at MCSs. However, the molecular mechanisms underlying lipid transfer and MCS formation are not well understood. Here, we first review two recent studies of extended synaptotagmin (E-Syt)-mediated membrane binding and lipid transfer using novel approaches. Then we describe mathematical models to quantify the kinetics of lipid transfer by shuttle LTPs based on a lipid exchange mechanism. We find that simple lipid mixing among membranes of similar composition and/or lipid partitioning among membranes of distinct composition can explain lipid transfer against a concentration gradient widely observed for LTPs. We predict that selective transport of lipids, but not membrane proteins, by bridge LTPs leads to osmotic membrane tension by analogy to the osmotic pressure across a semipermeable membrane. A gradient of such tension and the conventional membrane tension may drive bulk lipid flow through bridge LTPs at a speed consistent with the fast membrane expansion observed in vivo. Finally, we discuss the implications of membrane tension and lipid transfer in organelle biogenesis. Overall, the quantitative models may help clarify the mechanisms of LTP-mediated MCS formation and lipid transfer.
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Affiliation(s)
- 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
| | - 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.,Present address: State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Avinash Kumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
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36
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Tan JX, Finkel T. A phosphoinositide signalling pathway mediates rapid lysosomal repair. Nature 2022; 609:815-821. [PMID: 36071159 PMCID: PMC9450835 DOI: 10.1038/s41586-022-05164-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 07/29/2022] [Indexed: 12/23/2022]
Abstract
Lysosomal dysfunction has been increasingly linked to disease and normal ageing1,2. Lysosomal membrane permeabilization (LMP), a hallmark of lysosome-related diseases, can be triggered by diverse cellular stressors3. Given the damaging contents of lysosomes, LMP must be rapidly resolved, although the underlying mechanisms are poorly understood. Here, using an unbiased proteomic approach, we show that LMP stimulates a phosphoinositide-initiated membrane tethering and lipid transport (PITT) pathway for rapid lysosomal repair. Upon LMP, phosphatidylinositol-4 kinase type 2α (PI4K2A) accumulates rapidly on damaged lysosomes, generating high levels of the lipid messenger phosphatidylinositol-4-phosphate. Lysosomal phosphatidylinositol-4-phosphate in turn recruits multiple oxysterol-binding protein (OSBP)-related protein (ORP) family members, including ORP9, ORP10, ORP11 and OSBP, to orchestrate extensive new membrane contact sites between damaged lysosomes and the endoplasmic reticulum. The ORPs subsequently catalyse robust endoplasmic reticulum-to-lysosome transfer of phosphatidylserine and cholesterol to support rapid lysosomal repair. Finally, the lipid transfer protein ATG2 is also recruited to damaged lysosomes where its activity is potently stimulated by phosphatidylserine. Independent of macroautophagy, ATG2 mediates rapid membrane repair through direct lysosomal lipid transfer. Together, our findings identify that the PITT pathway maintains lysosomal membrane integrity, with important implications for numerous age-related diseases characterized by impaired lysosomal function.
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Affiliation(s)
- Jay Xiaojun Tan
- Aging Institute, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Toren Finkel
- Aging Institute, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
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37
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Park JS, Hu Y, Hollingsworth NM, Miltenberger-Miltenyi G, Neiman AM. Interaction between VPS13A and the XK scramblase is important for VPS13A function in humans. J Cell Sci 2022; 135:jcs260227. [PMID: 35950506 PMCID: PMC9482346 DOI: 10.1242/jcs.260227] [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: 05/09/2022] [Accepted: 08/02/2022] [Indexed: 11/20/2022] Open
Abstract
VPS13 family proteins form conduits between the membranes of different organelles through which lipids are transferred. In humans, there are four VPS13 paralogs, and mutations in the genes encoding each of them are associated with different inherited disorders. VPS13 proteins contain multiple conserved domains. The Vps13 adaptor-binding (VAB) domain binds to adaptor proteins that recruit VPS13 to specific membrane contact sites. This work demonstrates the importance of a different domain in VPS13A function. The pleckstrin homology (PH) domain at the C-terminal region of VPS13A is required to form a complex with the XK scramblase and for the co-localization of VPS13A with XK within the cell. Alphafold modeling was used to predict an interaction surface between VPS13A and XK. Mutations in this region disrupt both complex formation and co-localization of the two proteins. Mutant VPS13A alleles found in patients with VPS13A disease truncate the PH domain. The phenotypic similarities between VPS13A disease and McLeod syndrome caused by mutations in VPS13A and XK, respectively, argue that loss of the VPS13A-XK complex is the basis of both diseases.
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Affiliation(s)
- Jae-Sook Park
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Yiying Hu
- Fish Core Unit, German Center for Neurodegenerative Diseases München (DZNE), 81377 Munich, Germany
- Munich Medical Research School (MMRS), 80336 Munich, Germany
| | - Nancy M. Hollingsworth
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | | | - Aaron M. Neiman
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5215, USA
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A partnership between the lipid scramblase XK and the lipid transfer protein VPS13A at the plasma membrane. Proc Natl Acad Sci U S A 2022; 119:e2205425119. [PMID: 35994651 PMCID: PMC9436381 DOI: 10.1073/pnas.2205425119] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chorea-acanthocytosis (ChAc) and McLeod syndrome are diseases with shared clinical manifestations caused by mutations in VPS13A and XK, respectively. Key features of these conditions are the degeneration of caudate neurons and the presence of abnormally shaped erythrocytes. XK belongs to a family of plasma membrane (PM) lipid scramblases whose action results in exposure of PtdSer at the cell surface. VPS13A is an endoplasmic reticulum (ER)-anchored lipid transfer protein with a putative role in the transport of lipids at contacts of the ER with other membranes. Recently VPS13A and XK were reported to interact by still unknown mechanisms. So far, however, there is no evidence for a colocalization of the two proteins at contacts of the ER with the PM, where XK resides, as VPS13A was shown to be localized at contacts between the ER and either mitochondria or lipid droplets. Here we show that VPS13A can also localize at ER-PM contacts via the binding of its PH domain to a cytosolic loop of XK, that such interaction is regulated by an intramolecular interaction within XK, and that both VPS13A and XK are highly expressed in the caudate neurons. Binding of the PH domain of VPS13A to XK is competitive with its binding to intracellular membranes that mediate other tethering functions of VPS13A. Our findings support a model according to which VPS13A-dependent lipid transfer between the ER and the PM is coupled to lipid scrambling within the PM. They raise the possibility that defective cell surface exposure of PtdSer may be responsible for neurodegeneration.
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In situ architecture of the lipid transport protein VPS13C at ER-lysosome membrane contacts. Proc Natl Acad Sci U S A 2022; 119:e2203769119. [PMID: 35858323 PMCID: PMC9303930 DOI: 10.1073/pnas.2203769119] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
VPS13 is a eukaryotic lipid transport protein localized at membrane contact sites. Previous studies suggested that it may transfer lipids between adjacent bilayers by a bridge-like mechanism. Direct evidence for this hypothesis from a full-length structure and from electron microscopy (EM) studies in situ is still missing, however. Here, we have capitalized on AlphaFold predictions to complement the structural information already available about VPS13 and to generate a full-length model of human VPS13C, the Parkinson's disease-linked VPS13 paralog localized at contacts between the endoplasmic reticulum (ER) and endo/lysosomes. Such a model predicts an ∼30-nm rod with a hydrophobic groove that extends throughout its length. We further investigated whether such a structure can be observed in situ at ER-endo/lysosome contacts. To this aim, we combined genetic approaches with cryo-focused ion beam (cryo-FIB) milling and cryo-electron tomography (cryo-ET) to examine HeLa cells overexpressing this protein (either full length or with an internal truncation) along with VAP, its anchoring binding partner at the ER. Using these methods, we identified rod-like densities that span the space separating the two adjacent membranes and that match the predicted structures of either full-length VPS13C or its shorter truncated mutant, thus providing in situ evidence for a bridge model of VPS13 in lipid transport.
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Hancock-Cerutti W, Wu Z, Xu P, Yadavalli N, Leonzino M, Tharkeshwar AK, Ferguson SM, Shadel GS, De Camilli P. ER-lysosome lipid transfer protein VPS13C/PARK23 prevents aberrant mtDNA-dependent STING signaling. J Cell Biol 2022; 221:e202106046. [PMID: 35657605 PMCID: PMC9170524 DOI: 10.1083/jcb.202106046] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 05/03/2022] [Indexed: 02/03/2023] Open
Abstract
Mutations in VPS13C cause early-onset, autosomal recessive Parkinson's disease (PD). We have established that VPS13C encodes a lipid transfer protein localized to contact sites between the ER and late endosomes/lysosomes. In the current study, we demonstrate that depleting VPS13C in HeLa cells causes an accumulation of lysosomes with an altered lipid profile, including an accumulation of di-22:6-BMP, a biomarker of the PD-associated leucine-rich repeat kinase 2 (LRRK2) G2019S mutation. In addition, the DNA-sensing cGAS-STING pathway, which was recently implicated in PD pathogenesis, is activated in these cells. This activation results from a combination of elevated mitochondrial DNA in the cytosol and a defect in the degradation of activated STING, a lysosome-dependent process. These results suggest a link between ER-lysosome lipid transfer and innate immune activation in a model human cell line and place VPS13C in pathways relevant to PD pathogenesis.
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Affiliation(s)
- William Hancock-Cerutti
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT
- MD/PhD Program, Yale School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Chevy Chase, MD
- 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
| | - Zheng Wu
- Department of Genetics, Yale School of Medicine, New Haven, CT
- Salk Institute for Biological Studies, La Jolla, CA
| | - Peng Xu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Chevy Chase, MD
- 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
| | - Narayana Yadavalli
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD
| | - Marianna Leonzino
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Chevy Chase, MD
- 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
| | | | - Shawn M. Ferguson
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- 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
| | | | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Chevy Chase, MD
- 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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Disease relevance of rare VPS13B missense variants for neurodevelopmental Cohen syndrome. Sci Rep 2022; 12:9686. [PMID: 35690661 PMCID: PMC9188546 DOI: 10.1038/s41598-022-13717-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/13/2022] [Indexed: 12/29/2022] Open
Abstract
Autosomal recessive Cohen syndrome is a neurodevelopmental disorder characterized by postnatal microcephaly, intellectual disability, and a typical facial gestalt. Genetic variants in VPS13B have been found to cause Cohen syndrome, but have also been linked to autism, retinal disease, primary immunodeficiency, and short stature. While it is well established that loss-of-function mutations of VPS13B cause Cohen syndrome, the relevance of missense variants for the pathomechanism remains unexplained. Here, we investigate their pathogenic effect through a systematic re-evaluation of clinical patient information, comprehensive in silico predictions, and in vitro testing of previously published missense variants. In vitro analysis of 10 subcloned VPS13B missense variants resulted in full-length proteins after transient overexpression. 6/10 VPS13B missense variants show reduced accumulation at the Golgi complex in the steady state. The overexpression of these 6/10 VPS13B missense variants did not rescue the Golgi fragmentation after the RNAi-mediated depletion of endogenous VPS13B. These results thus validate 6/10 missense variants as likely pathogenic according to the classification of the American College of Medical Genetics through the integration of clinical, genetic, in silico, and experimental data. In summary, we state that exact variant classification should be the first step towards elucidating the pathomechanisms of genetically inherited neuronal diseases.
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Hanna MG, Suen PH, Wu Y, Reinisch KM, De Camilli P. SHIP164 is a chorein motif lipid transfer protein that controls endosome-Golgi membrane traffic. J Cell Biol 2022; 221:e202111018. [PMID: 35499567 PMCID: PMC9067936 DOI: 10.1083/jcb.202111018] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 03/07/2022] [Accepted: 04/08/2022] [Indexed: 02/03/2023] Open
Abstract
Cellular membranes differ in protein and lipid composition as well as in the protein-lipid ratio. Thus, progression of membranous organelles along traffic routes requires mechanisms to control bilayer lipid chemistry and their abundance relative to proteins. The recent structural and functional characterization of VPS13-family proteins has suggested a mechanism through which lipids can be transferred in bulk from one membrane to another at membrane contact sites, and thus independently of vesicular traffic. Here, we show that SHIP164 (UHRF1BP1L) shares structural and lipid transfer properties with these proteins and is localized on a subpopulation of vesicle clusters in the early endocytic pathway whose membrane cargo includes the cation-independent mannose-6-phosphate receptor (MPR). Loss of SHIP164 disrupts retrograde traffic of these organelles to the Golgi complex. Our findings raise the possibility that bulk transfer of lipids to endocytic membranes may play a role in their traffic.
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Affiliation(s)
- Michael G. Hanna
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Patreece H. Suen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Yumei Wu
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT
- Kavli Institue for Neuroscience, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
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43
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The Association of Lipids with Amyloid Fibrils. J Biol Chem 2022; 298:102108. [PMID: 35688209 PMCID: PMC9293637 DOI: 10.1016/j.jbc.2022.102108] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/31/2022] [Accepted: 06/03/2022] [Indexed: 01/02/2023] Open
Abstract
Amyloid formation continues to be a widely studied area because of its association with numerous diseases, such as Alzheimer’s and Parkinson’s diseases. Despite a large body of work on protein aggregation and fibril formation, there are still significant gaps in our understanding of the factors that differentiate toxic amyloid formation in vivo from alternative misfolding pathways. In addition to proteins, amyloid fibrils are often associated in their cellular context with several types of molecule, including carbohydrates, polyanions, and lipids. This review focuses in particular on evidence for the presence of lipids in amyloid fibrils and the routes by which those lipids may become incorporated. Chemical analyses of fibril composition, combined with studies to probe the lipid distribution around fibrils, provide evidence that in some cases, lipids have a strong association with fibrils. In addition, amyloid fibrils formed in the presence of lipids have distinct morphologies and material properties. It is argued that lipids are an integral part of many amyloid deposits in vivo, where their presence has the potential to influence the nucleation, morphology, and mechanical properties of fibrils. The role of lipids in these structures is therefore worthy of further study.
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Kaminska J, Soczewka P, Rzepnikowska W, Zoladek T. Yeast as a Model to Find New Drugs and Drug Targets for VPS13-Dependent Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms23095106. [PMID: 35563497 PMCID: PMC9104724 DOI: 10.3390/ijms23095106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 12/10/2022] Open
Abstract
Mutations in human VPS13A-D genes result in rare neurological diseases, including chorea-acanthocytosis. The pathogenesis of these diseases is poorly understood, and no effective treatment is available. As VPS13 genes are evolutionarily conserved, the effects of the pathogenic mutations could be studied in model organisms, including yeast, where one VPS13 gene is present. In this review, we summarize advancements obtained using yeast. In recent studies, vps13Δ and vps13-I2749 yeast mutants, which are models of chorea-acanthocytosis, were used to screen for multicopy and chemical suppressors. Two of the suppressors, a fragment of the MYO3 and RCN2 genes, act by downregulating calcineurin activity. In addition, vps13Δ suppression was achieved by using calcineurin inhibitors. The other group of multicopy suppressors were genes: FET4, encoding iron transporter, and CTR1, CTR3 and CCC2, encoding copper transporters. Mechanisms of their suppression rely on causing an increase in the intracellular iron content. Moreover, among the identified chemical suppressors were copper ionophores, which require a functional iron uptake system for activity, and flavonoids, which bind iron. These findings point at areas for further investigation in a higher eukaryotic model of VPS13-related diseases and to new therapeutic targets: calcium signalling and copper and iron homeostasis. Furthermore, the identified drugs are interesting candidates for drug repurposing for these diseases.
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Affiliation(s)
- Joanna Kaminska
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland; (J.K.); (P.S.)
| | - Piotr Soczewka
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland; (J.K.); (P.S.)
| | - Weronika Rzepnikowska
- Neuromuscular Unit, Mossakowski Medical Research Institute, Polish Academy of Sciences, 02-106 Warsaw, Poland;
| | - Teresa Zoladek
- Institute of Biochemistry and Biophysics Polish Academy of Sciences, 02-106 Warsaw, Poland; (J.K.); (P.S.)
- Correspondence:
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Toulmay A, Whittle FB, Yang J, Bai X, Diarra J, Banerjee S, Levine TP, Golden A, Prinz WA. Vps13-like proteins provide phosphatidylethanolamine for GPI anchor synthesis in the ER. J Biophys Biochem Cytol 2022; 221:212952. [PMID: 35015055 PMCID: PMC8757616 DOI: 10.1083/jcb.202111095] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022] Open
Abstract
Glycosylphosphatidylinositol (GPI) is a glycolipid membrane anchor found on surface proteins in all eukaryotes. It is synthesized in the ER membrane. Each GPI anchor requires three molecules of ethanolamine phosphate (P-Etn), which are derived from phosphatidylethanolamine (PE). We found that efficient GPI anchor synthesis in Saccharomyces cerevisiae requires Csf1; cells lacking Csf1 accumulate GPI precursors lacking P-Etn. Structure predictions suggest Csf1 is a tube-forming lipid transport protein like Vps13. Csf1 is found at contact sites between the ER and other organelles. It interacts with the ER protein Mcd4, an enzyme that adds P-Etn to nascent GPI anchors, suggesting Csf1 channels PE to Mcd4 in the ER at contact sites to support GPI anchor biosynthesis. CSF1 has orthologues in Caenorhabditis elegans (lpd-3) and humans (KIAA1109/TWEEK); mutations in KIAA1109 cause the autosomal recessive neurodevelopmental disorder Alkuraya-Kučinskas syndrome. Knockout of lpd-3 and knockdown of KIAA1109 reduced GPI-anchored proteins on the surface of cells, suggesting Csf1 orthologues in human cells support GPI anchor biosynthesis.
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Affiliation(s)
- Alexandre Toulmay
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Fawn B Whittle
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Jerry Yang
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Xiaofei Bai
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Jessica Diarra
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Subhrajit Banerjee
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - Tim P Levine
- University College London, Institute of Ophthalmology, London, UK
| | - Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
| | - William A Prinz
- Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD
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Melia TJ, Reinisch KM. A possible role for VPS13-family proteins in bulk lipid transfer, membrane expansion and organelle biogenesis. J Cell Sci 2022; 135:274675. [PMID: 35267021 PMCID: PMC8976877 DOI: 10.1242/jcs.259357] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
At organelle–organelle contact sites, proteins have long been known to facilitate the rapid movement of lipids. Classically, this lipid transport involves the extraction of single lipids into a hydrophobic pocket on a lipid transport protein. Recently, a new class of lipid transporter has been described with physical characteristics that suggest these proteins are likely to function differently. They possess long hydrophobic tracts that can bind many lipids at once and physically span the entire gulf between membranes at contact sites, suggesting that they may act as bridges to facilitate bulk lipid flow. Here, we review what has been learned regarding the structure and function of this class of lipid transporters, whose best characterized members are VPS13 and ATG2 proteins, and their apparent coordination with other lipid-mobilizing proteins on organelle membranes. We also discuss the prevailing hypothesis in the field, that this type of lipid transport may facilitate membrane expansion through the bulk delivery of lipids, as well as other emerging hypotheses and questions surrounding these novel lipid transport proteins. Summary: We discuss emerging roles of VPS13-family proteins in vesicle-independent bulk lipid transport between organelles, the possible functions of such transport and the underlying molecular mechanisms.
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Affiliation(s)
- Thomas J Melia
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA
| | - Karin M Reinisch
- Department of Cell Biology, Yale School of Medicine, New Haven, CT 06520, USA.,Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
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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: 10] [Impact Index Per Article: 5.0] [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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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: 30] [Impact Index Per Article: 15.0] [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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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: 14] [Impact Index Per Article: 7.0] [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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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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