1
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Hamaï A, Drin G. Specificity of lipid transfer proteins: An in vitro story. Biochimie 2024:S0300-9084(24)00217-7. [PMID: 39304019 DOI: 10.1016/j.biochi.2024.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 09/06/2024] [Accepted: 09/17/2024] [Indexed: 09/22/2024]
Abstract
Lipids, which are highly diverse, are finely distributed between organelle membranes and the plasma membrane (PM) of eukaryotic cells. As a result, each compartment has its own lipid composition and molecular identity, which is essential for the functional fate of many proteins. This distribution of lipids depends on two main processes: lipid synthesis, which takes place in different subcellular regions, and the transfer of these lipids between and across membranes. This review will discuss the proteins that carry lipids throughout the cytosol, called LTPs (Lipid Transfer Proteins). More than the modes of action or biological roles of these proteins, we will focus on the in vitro strategies employed during the last 60 years to address a critical question: What are the lipid ligands of these LTPs? We will describe the extent to which these strategies, combined with structural data and investigations in cells, have made it possible to discover proteins, namely ORPs, Sec14, PITPs, STARDs, Ups/PRELIs, START-like, SMP-domain containing proteins, and bridge-like LTPs, which compose some of the main eukaryotic LTP families, and their lipid ligands. We will see how these approaches have played a central role in cell biology, showing that LTPs can connect distant metabolic branches, modulate the composition of cell membranes, and even create new subcellular compartments.
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Affiliation(s)
- Amazigh Hamaï
- Université Côte d'Azur, CNRS and Inserm, Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, 660 route des lucioles, 06560, Valbonne Sophia Antipolis, France
| | - Guillaume Drin
- Université Côte d'Azur, CNRS and Inserm, Institut de Pharmacologie Moléculaire et Cellulaire, UMR 7275, 660 route des lucioles, 06560, Valbonne Sophia Antipolis, France.
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2
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Bandyopadhyay S, Adebayo D, Obaseki E, Hariri H. Lysosomal membrane contact sites: Integrative hubs for cellular communication and homeostasis. CURRENT TOPICS IN MEMBRANES 2024; 93:85-116. [PMID: 39181579 DOI: 10.1016/bs.ctm.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
Lysosomes are more than just cellular recycling bins; they play a crucial role in regulating key cellular functions. Proper lysosomal function is essential for growth pathway regulation, cell proliferation, and metabolic homeostasis. Impaired lysosomal function is associated with lipid storage disorders and neurodegenerative diseases. Lysosomes form extensive and dynamic close contacts with the membranes of other organelles, including the endoplasmic reticulum, mitochondria, peroxisomes, and lipid droplets. These membrane contacts sites (MCSs) are vital for many lysosomal functions. In this chapter, we will explore lysosomal MCSs focusing on the machinery that mediates these contacts, how they are regulated, and their functional implications on physiology and pathology.
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Affiliation(s)
- Sumit Bandyopadhyay
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Daniel Adebayo
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Eseiwi Obaseki
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States.
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3
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Ajiki M, Yoshikawa M, Miyazaki T, Kawasaki A, Aoki K, Nakatsu F, Tsukiji S. ORP9-PH domain-based fluorescent reporters for visualizing phosphatidylinositol 4-phosphate dynamics in living cells. RSC Chem Biol 2024; 5:544-555. [PMID: 38846081 PMCID: PMC11151866 DOI: 10.1039/d3cb00232b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 04/15/2024] [Indexed: 06/09/2024] Open
Abstract
Fluorescent reporters that visualize phosphatidylinositol 4-phosphate (PI4P) in living cells are indispensable to elucidate the roles of this fundamental lipid in cell physiology. However, currently available PI4P reporters have limitations, such as Golgi-biased localization and low detection sensitivity. Here, we present a series of fluorescent PI4P reporters based on the pleckstrin homology (PH) domain of oxysterol-binding protein-related protein 9 (ORP9). We show that the green fluorescent protein AcGFP1-tagged ORP9-PH domain can be used as a fluorescent PI4P reporter to detect cellular PI4P across its wide distribution at multiple cellular locations, including the plasma membrane (PM), Golgi, endosomes, and lysosomes with high specificity and contrast. We also developed blue, red, and near-infrared fluorescent PI4P reporters suitable for multicolor fluorescence imaging experiments. Finally, we demonstrate the utility of the ORP9-PH domain-based reporter to visualize dynamic changes in the PI4P distribution and level in living cells upon synthetic ER-PM membrane contact manipulation and GPCR stimulation. This work offers a new set of genetically encoded fluorescent PI4P reporters that are practically useful for the study of PI4P biology.
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Affiliation(s)
- Moeka Ajiki
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
| | - Masaru Yoshikawa
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
| | - Tomoki Miyazaki
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
| | - Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University 1-757 Asahimachi, Chuo-ku Niigata 951-8510 Japan
| | - Kazuhiro Aoki
- Quantitative Biology Research Group, Exploratory Research Center on Life and Living Systems (ExCELLS), National Institutes of Natural Sciences 5-1 Higashiyama, Myodaiji-cho Okazaki Aichi 444-8787 Japan
- Division of Quantitative Biology, National Institute for Basic Biology, National Institutes of Natural Sciences 5-1 Higashiyama, Myodaiji-cho Okazaki Aichi 444-8787 Japan
- Department of Basic Biology, Faculty of Life Science, SOKENDAI (The Graduate University for Advanced Studies) 5-1 Higashiyama, Myodaiji-cho Okazaki Aichi 444-8787 Japan
| | - Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Graduate School of Medical and Dental Sciences, Niigata University 1-757 Asahimachi, Chuo-ku Niigata 951-8510 Japan
| | - Shinya Tsukiji
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
- Department of Nanopharmaceutical Sciences, Nagoya Institute of Technology Gokiso-cho, Showa-ku Nagoya 466-8555 Japan
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4
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Li YE, Norris DM, Xiao FN, Pandzic E, Whan RM, Fok S, Zhou M, Du G, Liu Y, Du X, Yang H. Phosphatidylserine regulates plasma membrane repair through tetraspanin-enriched macrodomains. J Cell Biol 2024; 223:e202307041. [PMID: 38530252 PMCID: PMC10964951 DOI: 10.1083/jcb.202307041] [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: 07/12/2023] [Revised: 11/30/2023] [Accepted: 03/11/2024] [Indexed: 03/27/2024] Open
Abstract
The integrity of the plasma membrane is critical to cell function and survival. Cells have developed multiple mechanisms to repair damaged plasma membranes. A key process during plasma membrane repair is to limit the size of the damage, which is facilitated by the presence of tetraspanin-enriched rings surrounding damage sites. Here, we identify phosphatidylserine-enriched rings surrounding damaged sites of the plasma membrane, resembling tetraspanin-enriched rings. Importantly, the formation of both the phosphatidylserine- and tetraspanin-enriched rings requires phosphatidylserine and its transfer proteins ORP5 and ORP9. Interestingly, ORP9, but not ORP5, is recruited to the damage sites, suggesting cells acquire phosphatidylserine from multiple sources upon plasma membrane damage. We further demonstrate that ORP9 contributes to efficient plasma membrane repair. Our results thus unveil a role for phosphatidylserine and its transfer proteins in facilitating the formation of tetraspanin-enriched macrodomains and plasma membrane repair.
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Affiliation(s)
- Yang E. Li
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Dougall M. Norris
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Fanqian N. Xiao
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Elvis Pandzic
- Katerina Gaus Light Microscopy Facility, Mark Wainwright Analytical Center, University of New South Wales, Sydney, Australia
| | - Renee M. Whan
- Katerina Gaus Light Microscopy Facility, Mark Wainwright Analytical Center, University of New South Wales, Sydney, Australia
| | - Sandra Fok
- Katerina Gaus Light Microscopy Facility, Mark Wainwright Analytical Center, University of New South Wales, Sydney, Australia
| | - Ming Zhou
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Guangwei Du
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Yang Liu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
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5
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Kulkarni PG, Mohire VM, Waghmare PP, Banerjee T. Interplay of mitochondria-associated membrane proteins and autophagy: Implications in neurodegeneration. Mitochondrion 2024; 76:101874. [PMID: 38514017 DOI: 10.1016/j.mito.2024.101874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 03/11/2024] [Accepted: 03/15/2024] [Indexed: 03/23/2024]
Abstract
Since the discovery of membrane contact sites between ER and mitochondria called mitochondria-associated membranes (MAMs), several pieces of evidence identified their role in the regulation of different cellular processes such as Ca2+ signalling, mitochondrial transport, and dynamics, ER stress, inflammation, glucose homeostasis, and autophagy. The integrity of these membranes was found to be essential for the maintenance of these cellular functions. Accumulating pieces of evidence suggest that MAMs serve as a platform for autophagosome formation. However, the alteration within MAMs structure is associated with the progression of neurodegenerative diseases. Dysregulated autophagy is a hallmark of neurodegeneration. Here, in this review, we highlight the present knowledge on MAMs, their structural composition, and their roles in different cellular functions. We also discuss the association of MAMs proteins with impaired autophagy and their involvement in the progression of neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Prakash G Kulkarni
- Department of Biotechnology, Savitribai Phule Pune University, Ganeshkhind Road, Pune 411007 India
| | - Vaibhavi M Mohire
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y Patil Vidyapeeth, Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033 India
| | - Pranjal P Waghmare
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y Patil Vidyapeeth, Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033 India
| | - Tanushree Banerjee
- Molecular Neuroscience Research Centre, Dr. D. Y. Patil Biotechnology & Bioinformatics Institute, Dr. D. Y Patil Vidyapeeth, Survey No 87/88, Mumbai Bangalore Express Highway, Tathawade, Pune 411 033 India; Infosys Ltd., SEZ unit VI, Plot No. 1, Rajiv Gandhi Infotech Park, Hinjawadi Phase I, Pune, Maharashtra 411057, India.
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6
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Monteiro-Cardoso VF, Giordano F. Emerging functions of the mitochondria-ER-lipid droplet three-way junction in coordinating lipid transfer, metabolism, and storage in cells. FEBS Lett 2024; 598:1252-1273. [PMID: 38774950 DOI: 10.1002/1873-3468.14893] [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: 02/05/2024] [Revised: 03/18/2024] [Accepted: 04/05/2024] [Indexed: 05/25/2024]
Abstract
Over the past two decades, we have witnessed a growing appreciation for the importance of membrane contact sites (CS) in facilitating direct communication between organelles. CS are tiny regions where the membranes of two organelles meet but do not fuse and allow the transfer of metabolites between organelles, playing crucial roles in the coordination of cellular metabolic activities. The significant advancements in imaging techniques and molecular and cell biology research have revealed that CS are more complex than what originally thought, and as they are extremely dynamic, they can remodel their shape, composition, and functions in accordance with metabolic and environmental changes and can occur between more than two organelles. Here, we describe how recent studies led to the identification of a three-way mitochondria-ER-lipid droplet CS and discuss the emerging functions of these contacts in maintaining lipid storage, homeostasis, and balance. We also summarize the properties and functions of key protein components localized at the mitochondria-ER-lipid droplet interface, with a special focus on lipid transfer proteins. Understanding tripartite CS is essential for unraveling the complexities of inter-organelle communication and cooperation within cells.
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Affiliation(s)
- Vera Filipa Monteiro-Cardoso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex, France
- Inserm U1280, Gif-sur-Yvette cedex, France
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex, France
- Inserm U1280, Gif-sur-Yvette cedex, France
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7
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Omi J, Kato T, Yoshihama Y, Sawada K, Kono N, Aoki J. Phosphatidylserine synthesis controls oncogenic B cell receptor signaling in B cell lymphoma. J Cell Biol 2024; 223:e202212074. [PMID: 38048228 PMCID: PMC10694799 DOI: 10.1083/jcb.202212074] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 09/13/2023] [Accepted: 11/09/2023] [Indexed: 12/06/2023] Open
Abstract
Cancer cells harness lipid metabolism to promote their own survival. We screened 47 cancer cell lines for survival dependency on phosphatidylserine (PS) synthesis using a PS synthase 1 (PTDSS1) inhibitor and found that B cell lymphoma is highly dependent on PS. Inhibition of PTDSS1 in B cell lymphoma cells caused a reduction of PS and phosphatidylethanolamine levels and an increase of phosphoinositide levels. The resulting imbalance of the membrane phospholipidome lowered the activation threshold for B cell receptor (BCR), a B cell-specific survival mechanism. BCR hyperactivation led to aberrant elevation of downstream Ca2+ signaling and subsequent apoptotic cell death. In a mouse xenograft model, PTDSS1 inhibition efficiently suppressed tumor growth and prolonged survival. Our findings suggest that PS synthesis may be a critical vulnerability of malignant B cell lymphomas that can be targeted pharmacologically.
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Affiliation(s)
- Jumpei Omi
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | | | | | - Koki Sawada
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Junken Aoki
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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8
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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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9
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Henkels KM, Miller TE, Naji A, van der Hoeven R, Liang H, Zhou Y, Hammond GR, Hancock JF, Cho KJ. Myotubularin-related proteins regulate KRAS function by controlling plasma membrane levels of polyphosphoinositides and phosphatidylserine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.22.576612. [PMID: 38328115 PMCID: PMC10849561 DOI: 10.1101/2024.01.22.576612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
KRAS is a small GTPase, ubiquitously expressed in mammalian cells, that functions as a molecular switch to regulate cell proliferation and differentiation. Oncogenic mutations that render KRAS constitutively active occur frequently in human cancers. KRAS must localize to the plasma membrane (PM) for biological activity. KRAS PM binding is mediated by interactions of the KRAS membrane anchor with phosphatidylserine (PtdSer), therefore, depleting PM PtdSer content abrogates KRAS PM binding and oncogenic function. From a genome-wide siRNA screen to search for genes that regulate KRAS PM localization, we identified a set of phosphatidylinositol (PI) 3-phosphatase family members: myotubularin-related (MTMR) proteins 2, 3, 4 and 7. Here we show that knockdown of MTMR 2/3/4/7 expression disrupts KRAS PM interactions. The molecular mechanism involves depletion of PM PI 4-phosphate (PI4P) levels, which in turn disrupts the subcellular localization and operation of oxysterol-binding protein related protein (ORP) 5, a PtdSer lipid transfer protein that maintains PM PtdSer content. Concomitantly, silencing MTMR 2/3/4/7 expression elevates PM levels of PI3P and reduces PM and total cellular levels of PtdSer. In summary we propose that the PI 3-phosphatase activity provided by MTMR proteins is required to generate PM PI for the synthesis of PM PI4P, which in turn, promotes the PM localization of PtdSer and KRAS.
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Affiliation(s)
- Karen M. Henkels
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Taylor E. Miller
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
| | - Ali Naji
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Ransome van der Hoeven
- Department of Diagnostic and Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Hong Liang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Gerald R.V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - John F. Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, USA
| | - Kwang-jin Cho
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
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10
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Doyle CP, Rectenwald A, Timple L, Hammond GRV. Orthogonal targeting of SAC1 to mitochondria implicates ORP2 as a major player in PM PI4P turnover. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.28.555163. [PMID: 37693626 PMCID: PMC10491111 DOI: 10.1101/2023.08.28.555163] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Oxysterol binding protein (OSBP)-related proteins (ORPs) 5 and 8 have been shown to deplete the lipid phosphatidylinositol 4-phosphate (PI4P) at sites of membrane contact between the endoplasmic reticulum (ER) and plasma membrane (PM). This is believed to be caused by transport of PI4P from the PM to the ER, where PI4P is degraded by an ER-localized SAC1 phosphatase. This is proposed to power the anti-port of phosphatidylserine (PS) lipids from ER to PM, up their concentration gradient. Alternatively, ORPs have been proposed to sequester PI4P, dependent on the concentration of their alternative lipid ligand. Here, we aimed to distinguish these possibilities in living cells by orthogonal targeting of PI4P transfer and degradation to PM-mitochondria contact sites. Surprisingly, we found that orthogonal targeting of SAC1 to mitochondria enhanced PM PI4P turnover independent of targeting to contact sites with the PM. This turnover could be slowed by knock-down of soluble ORP2, which also has a major impact on PM PI4P levels even without SAC1 over-expression. The data reveal a role for contact site-independent modulation of PM PI4P levels and lipid antiport.
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Affiliation(s)
- Colleen P Doyle
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Andrew Rectenwald
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Liz Timple
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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11
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Doyle CP, Rectenwald A, Timple L, Hammond GRV. Orthogonal Targeting of SAC1 to Mitochondria Implicates ORP2 as a Major Player in PM PI4P Turnover. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241229272. [PMID: 38327560 PMCID: PMC10848804 DOI: 10.1177/25152564241229272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 02/09/2024]
Abstract
Oxysterol-binding protein (OSBP)-related proteins (ORPs) 5 and 8 have been shown to deplete the lipid phosphatidylinositol 4-phosphate (PI4P) at sites of membrane contact between the endoplasmic reticulum (ER) and plasma membrane (PM). This is believed to be caused by transport of PI4P from the PM to the ER, where PI4P is degraded by an ER-localized SAC1 phosphatase. This is proposed to power the anti-port of phosphatidylserine (PS) lipids from ER to PM, up their concentration gradient. Alternatively, ORPs have been proposed to sequester PI4P, dependent on the concentration of their alternative lipid ligand. Here, we aimed to distinguish these possibilities in living cells by orthogonal targeting of PI4P transfer and degradation to PM-mitochondria contact sites. Surprisingly, we found that orthogonal targeting of SAC1 to mitochondria enhanced PM PI4P turnover independent of targeting to contact sites with the PM. This turnover could be slowed by knock-down of soluble ORP2, which also has a major impact on PM PI4P levels even without SAC1 over-expression. The data reveal a role for contact site-independent modulation of PM PI4P levels and lipid antiport.
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Affiliation(s)
- Colleen P. Doyle
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Andrew Rectenwald
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Liz Timple
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Gerald R. V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
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12
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Olkkonen VM, Ikonen E. Getting to Grips with the Oxysterol-Binding Protein Family - a Forty Year Perspective. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241273598. [PMID: 39210909 PMCID: PMC11359446 DOI: 10.1177/25152564241273598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2024] [Accepted: 07/08/2024] [Indexed: 09/04/2024]
Abstract
This review discusses how research around the oxysterol-binding protein family has evolved. We briefly summarize how this protein family, designated OSBP-related (ORP) or OSBP-like (OSBPL) proteins, was discovered, how protein domains highly conserved among family members between taxa paved the way for understanding their mechanisms of action, and how insights into protein structural and functional features help to understand their versatility as lipid transporters. We also discuss questions and future avenues of research opened by these findings. The investigations on oxysterol-binding protein family serve as a real-life example of the notion that science often advances as a collective effort of multiple lines of enquiry, including serendipitous routes. While original articles invariably explain the motivation of the research undertaken in rational terms, the actual paths to findings may be less intentional. Fortunately, this does not reduce the impact of the discoveries made. Besides hopefully providing a useful account of ORP family proteins, we aim to convey this message.
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Affiliation(s)
- Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Faculty of Medicine, Dept of Anatomy and Stem Cells and Metabolism Research Program, University of Helsinki, Helsinki, Finland
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13
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Chung WY, Ahuja M, McNally BA, Leibow SR, Ohman HKE, Movahed Abtahi A, Muallem S. PtdSer as a signaling lipid determined by privileged localization of ORP5 and ORP8 at ER/PM junctional foci to determine PM and ER PtdSer/PI(4)P ratio and cell function. Proc Natl Acad Sci U S A 2023; 120:e2301410120. [PMID: 37607230 PMCID: PMC10469337 DOI: 10.1073/pnas.2301410120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/11/2023] [Indexed: 08/24/2023] Open
Abstract
The membrane contact site ER/PM junctions are hubs for signaling pathways, including Ca2+ signaling. Phosphatidylserine (PtdSer) mediates various physiological functions; however, junctional PtdSer composition and the role of PtdSer in Ca2+ signaling and Ca2+-dependent gene regulation are not understood. Here, we show that STIM1-formed junctions are required for PI(4)P/PtdSer exchange by ORP5 and ORP8, which have reciprocal lipid exchange modes and function as a rheostat that sets the junctional PtdSer/PI(4)P ratio. Targeting the ORP5 and ORP8 and their lipid transfer ORD domains to PM subdomains revealed that ORP5 sets low and ORP8 high junctional PI(4)P/PtdSer ratio that controls STIM1-STIM1 and STIM1-Orai1 interaction and the activity of the SERCA pump to determine the pattern of receptor-evoked Ca2+ oscillations, and consequently translocation of NFAT to the nucleus. Significantly, targeting the ORP5 and ORP8 ORDs to the STIM1 ER subdomain reversed their function. Notably, changing PI(4)P/PtdSer ratio by hydrolysis of PM or ER PtdSer with targeted PtdSer-specific PLA1a1 reproduced the ORPs function. The function of the ORPs is determined both by their differential lipid exchange modes and by privileged localization at the ER/PM subdomains. These findings reveal a role of PtdSer as a signaling lipid that controls the available PM PI(4)P, the unappreciated role of ER PtdSer in cell function, and the diversity of the ER/PM junctions. The effect of PtdSer on the junctional PI(4)P level should have multiple implications in cellular signaling and functions.
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Affiliation(s)
- Woo Young Chung
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Malini Ahuja
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Beth A. McNally
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Spencer R. Leibow
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Henry K. E. Ohman
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Ava Movahed Abtahi
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD20892
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Eisenreichova A, Klima M, Anila MM, Koukalova A, Humpolickova J, Różycki B, Boura E. Crystal Structure of the ORP8 Lipid Transport ORD Domain: Model of Lipid Transport. Cells 2023; 12:1974. [PMID: 37566053 PMCID: PMC10417380 DOI: 10.3390/cells12151974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/12/2023] Open
Abstract
ORPs are lipid-transport proteins belonging to the oxysterol-binding protein family. They facilitate the transfer of lipids between different intracellular membranes, such as the ER and plasma membrane. We have solved the crystal structure of the ORP8 lipid transport domain (ORD8). The ORD8 exhibited a β-barrel fold composed of anti-parallel β-strands, with three α-helices replacing β-strands on one side. This mixed alpha-beta structure was consistent with previously solved structures of ORP2 and ORP3. A large cavity (≈1860 Å3) within the barrel was identified as the lipid-binding site. Although we were not able to obtain a lipid-bound structure, we used computer simulations based on our crystal structure to dock PS and PI4P molecules into the putative lipid-binding site of the ORD8. Comparative experiments between the short ORD8ΔLid (used for crystallography) and the full-length ORD8 (lid containing) revealed the lid's importance for stable lipid binding. Fluorescence assays revealed different transport efficiencies for PS and PI4P, with the lid slowing down transport and stabilizing cargo. Coarse-grained simulations highlighted surface-exposed regions and hydrophobic interactions facilitating lipid bilayer insertion. These findings enhance our comprehension of ORD8, its structure, and lipid transport mechanisms, as well as provide a structural basis for the design of potential inhibitors.
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Affiliation(s)
- Andrea Eisenreichova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Martin Klima
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Midhun Mohan Anila
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland; (M.M.A.); (B.R.)
| | - Alena Koukalova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw, Poland; (M.M.A.); (B.R.)
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry AS CR, v.v.i., Flemingovo nam. 2., 166 10 Prague, Czech Republic; (A.E.); (M.K.); (A.K.); (J.H.)
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15
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Parra V, Monaco G, Morciano G, Santulli G. Editorial: Mitochondrial remodeling and dynamic inter-organellar contacts in cardiovascular physiopathology-Volume II. Front Cell Dev Biol 2023; 11:1240207. [PMID: 37427376 PMCID: PMC10325657 DOI: 10.3389/fcell.2023.1240207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 06/16/2023] [Indexed: 07/11/2023] Open
Affiliation(s)
- Valentina Parra
- Advanced Center of Chronic Diseases (ACCDiS), Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago, Chile
| | - Giovanni Monaco
- Center for Innovation and Stimulation of Drug Discovery (CISTIM), Leuven, Belgium
| | - Giampaolo Morciano
- Section of Experimental Medicine, Laboratory for Technologies of Advanced Therapies (LTTA), Department of Medical Sciences, University of Ferrara, Ferrara, Italy
- Maria Cecilia Hospital, GVM Care and Research, Cotignola, Italy
| | - Gaetano Santulli
- Division of Cardiology, Department of Medicine, Albert Einstein College of Medicine, Wilf Family Cardiovascular Research Institute and Einstein Institute for Aging Research, New York, NY, United States
- Department of Molecular Pharmacology, Einstein-Sinai Diabetes Research Center (ES-DRC), Fleischer Institute for Diabetes and Metabolism (FIDAM), Montefiore University Hospital, New York, NY, United States
- International Translational Research and Medical Education Academic Research Unit (ITME), Department of Advanced Biomedical Sciences, “Federico II” University, Naples, Italy
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16
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Tang T, Hasan M, Capelluto DGS. Phafins Are More Than Phosphoinositide-Binding Proteins. Int J Mol Sci 2023; 24:ijms24098096. [PMID: 37175801 PMCID: PMC10178739 DOI: 10.3390/ijms24098096] [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: 03/22/2023] [Revised: 04/27/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Phafins are PH (Pleckstrin Homology) and FYVE (Fab1, YOTB, Vac1, and EEA1) domain-containing proteins. The Phafin protein family is classified into two groups based on their sequence homology and functional similarity: Phafin1 and Phafin2. This protein family is unique because both the PH and FYVE domains bind to phosphatidylinositol 3-phosphate [PtdIns(3)P], a phosphoinositide primarily found in endosomal and lysosomal membranes. Phafin proteins act as PtdIns(3)P effectors in apoptosis, endocytic cargo trafficking, and autophagy. Additionally, Phafin2 is recruited to macropinocytic compartments through coincidence detection of PtdIns(3)P and PtdIns(4)P. Membrane-associated Phafins serve as adaptor proteins that recruit other binding partners. In addition to the phosphoinositide-binding domains, Phafin proteins present a poly aspartic acid motif that regulates membrane binding specificity. In this review, we summarize the involvement of Phafins in several cellular pathways and their potential physiological functions while highlighting the similarities and differences between Phafin1 and Phafin2. Besides, we discuss research perspectives for Phafins.
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Affiliation(s)
- Tuoxian Tang
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mahmudul Hasan
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA
| | - Daniel G S Capelluto
- Protein Signaling Domains Laboratory, Department of Biological Sciences, Fralin Life Sciences Institute and Center for Soft Matter and Biological Physics, Virginia Tech, Blacksburg, VA 24061, USA
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17
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Ivanova A, Atakpa-Adaji P. Phosphatidylinositol 4,5-bisphosphate and calcium at ER-PM junctions - Complex interplay of simple messengers. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119475. [PMID: 37098393 DOI: 10.1016/j.bbamcr.2023.119475] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/05/2023] [Accepted: 04/03/2023] [Indexed: 04/27/2023]
Abstract
Endoplasmic reticulum-plasma membrane contact sites (ER-PM MCS) are a specialised domain involved in the control of Ca2+ dynamics and various Ca2+-dependent cellular processes. Intracellular Ca2+ signals are broadly supported by Ca2+ release from intracellular Ca2+ channels such as inositol 1,4,5-trisphosphate receptors (IP3Rs) and subsequent store-operated Ca2+ entry (SOCE) across the PM to replenish store content. IP3Rs sit in close proximity to the PM where they can easily access newly synthesised IP3, interact with binding partners such as actin, and localise adjacent to ER-PM MCS populated by the SOCE machinery, STIM1-2 and Orai1-3, to possibly form a locally regulated unit of Ca2+ influx. PtdIns(4,5)P2 is a multiplex regulator of Ca2+ signalling at the ER-PM MCS interacting with multiple proteins at these junctions such as actin and STIM1, whilst also being consumed as a substrate for phospholipase C to produce IP3 in response to extracellular stimuli. In this review, we consider the mechanisms regulating the synthesis and turnover of PtdIns(4,5)P2 via the phosphoinositide cycle and its significance for sustained signalling at the ER-PM MCS. Furthermore, we highlight recent insights into the role of PtdIns(4,5)P2 in the spatiotemporal organization of signalling at ER-PM junctions and raise outstanding questions on how this multi-faceted regulation occurs.
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Affiliation(s)
- Adelina Ivanova
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK.
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18
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Vormittag S, Ende RJ, Derré I, Hilbi H. Pathogen vacuole membrane contact sites - close encounters of the fifth kind. MICROLIFE 2023; 4:uqad018. [PMID: 37223745 PMCID: PMC10117887 DOI: 10.1093/femsml/uqad018] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/30/2023] [Accepted: 04/06/2023] [Indexed: 05/25/2023]
Abstract
Vesicular trafficking and membrane fusion are well-characterized, versatile, and sophisticated means of 'long range' intracellular protein and lipid delivery. Membrane contact sites (MCS) have been studied in far less detail, but are crucial for 'short range' (10-30 nm) communication between organelles, as well as between pathogen vacuoles and organelles. MCS are specialized in the non-vesicular trafficking of small molecules such as calcium and lipids. Pivotal MCS components important for lipid transfer are the VAP receptor/tether protein, oxysterol binding proteins (OSBPs), the ceramide transport protein CERT, the phosphoinositide phosphatase Sac1, and the lipid phosphatidylinositol 4-phosphate (PtdIns(4)P). In this review, we discuss how these MCS components are subverted by bacterial pathogens and their secreted effector proteins to promote intracellular survival and replication.
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Affiliation(s)
| | | | - Isabelle Derré
- Corresponding author. Department of Microbiology, Immunology and Cancer Biology, University of Virginia, 1340 Jefferson Park Ave, Charlottesville, VA 22908, United States. Tel: +1-434-924-2330; E-mail:
| | - Hubert Hilbi
- Corresponding author. Institute of Medical Microbiology, University of Zürich, Gloriastrasse 30, 8006 Zürich, Switzerland. Tel: +41-44-634-2650; E-mail:
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Wang Y, Li Z, Wang X, Zhao Z, Jiao L, Liu R, Wang K, Ma R, Yang Y, Chen G, Wang Y, Bian X. Insights into membrane association of the SMP domain of extended synaptotagmin. Nat Commun 2023; 14:1504. [PMID: 36932127 PMCID: PMC10023780 DOI: 10.1038/s41467-023-37202-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
The Synaptotagmin-like Mitochondrial-lipid-binding Protein (SMP) domain is a newly identified lipid transfer module present in proteins that regulate lipid homeostasis at membrane contact sites (MCSs). However, how the SMP domain associates with the membrane to extract and unload lipids is unclear. Here, we performed in vitro DNA brick-assisted lipid transfer assays and in silico molecular dynamics simulations to investigate the molecular basis of the membrane association by the SMP domain of extended synaptotagmin (E-Syt), which tethers the tubular endoplasmic reticulum (ER) to the plasma membrane (PM). We demonstrate that the SMP domain uses its tip region to recognize the extremely curved subdomain of tubular ER and the acidic-lipid-enriched PM for highly efficient lipid transfer. Supporting these findings, disruption of these mechanisms results in a defect in autophagosome biogenesis contributed by E-Syt. Our results suggest a model that provides a coherent picture of the action of the SMP domain at MCSs.
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Affiliation(s)
- Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Zhenni Li
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Xinyu Wang
- College of Life Sciences, Nankai University, Tianjin, China
| | - Ziyuan Zhao
- College of Life Sciences, Nankai University, Tianjin, China
| | - Li Jiao
- College of Life Sciences, Nankai University, Tianjin, China
| | - Ruming Liu
- College of Life Sciences, Nankai University, Tianjin, China
| | - Keying Wang
- College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Rui Ma
- College of Physical Science and Technology, Xiamen University, Xiamen, China
| | - Yang Yang
- Institute of Molecular Medicine, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Guo Chen
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, China.
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, China.
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Frontiers Science Center for Cell Responses, Nankai University, Tianjin, China.
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20
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He R, Liu F, Wang H, Huang S, Xu K, Zhang C, Liu Y, Yu H. ORP9 and ORP10 form a heterocomplex to transfer phosphatidylinositol 4-phosphate at ER-TGN contact sites. Cell Mol Life Sci 2023; 80:77. [PMID: 36853333 PMCID: PMC11072704 DOI: 10.1007/s00018-023-04728-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 02/15/2023] [Accepted: 02/15/2023] [Indexed: 03/01/2023]
Abstract
Oxysterol-binding protein (OSBP) and its related proteins (ORPs) are a family of lipid transfer proteins (LTPs) that mediate non-vesicular lipid transport. ORP9 and ORP10, members of the OSBP/ORPs family, are located at the endoplasmic reticulum (ER)-trans-Golgi network (TGN) membrane contact sites (MCSs). It remained unclear how they mediate lipid transport. In this work, we discovered that ORP9 and ORP10 form a binary complex through intermolecular coiled-coil (CC) domain-CC domain interaction. The PH domains of ORP9 and ORP10 specially interact with phosphatidylinositol 4-phosphate (PI4P), mediating the TGN targeting. The ORP9-ORP10 complex plays a critical role in regulating PI4P levels at the TGN. Using in vitro reconstitution assays, we observed that while full-length ORP9 efficiently transferred PI4P between two apposed membranes, the lipid transfer kinetics was further accelerated by ORP10. Interestingly, our data showed that the PH domains of ORP9 and ORP10 participate in membrane tethering simultaneously, whereas ORDs of both ORP9 and ORP10 are required for lipid transport. Furthermore, our data showed that the depletion of ORP9 and ORP10 led to increased vesicle transport to the plasma membrane (PM). These findings demonstrate that ORP9 and ORP10 form a binary complex through the CC domains, maintaining PI4P homeostasis at ER-TGN MCSs and regulating vesicle trafficking.
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Affiliation(s)
- Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Furong Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Hui Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Shuai Huang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Kai Xu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China
| | - Conggang Zhang
- School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China.
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, 210023, China.
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21
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Balla T, Gulyas G, Mandal A, Alvarez-Prats A, Niu Y, Kim YJ, Pemberton J. Roles of Phosphatidylinositol 4-Phosphorylation in Non-vesicular Cholesterol Trafficking. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:327-352. [PMID: 36988887 PMCID: PMC11135459 DOI: 10.1007/978-3-031-21547-6_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Cholesterol (Chol) is an essential component of all eukaryotic cell membranes that affects the function of numerous peripheral as well as integral membrane proteins. Chol is synthesized in the ER, but it is selectively enriched within the plasma membrane (PM) and other endomembranes, which requires Chol to cross the aqueous phase of the cytoplasm. In addition to the classical vesicular trafficking pathways that are known to facilitate the bulk transport of membrane intermediates, Chol is also transported via non-vesicular lipid transfer proteins that work primarily within specialized membrane contact sites. Some of these transport pathways work against established concentration gradients and hence require energy. Recent studies highlight the unique role of phosphoinositides (PPIns), and phosphatidylinositol 4-phosphate (PI4P) in particular, for the control of non-vesicular Chol transport. In this chapter, we will review the emerging connection between Chol, PPIns, and lipid transfer proteins that include the important family of oxysterol-binding protein related proteins, or ORPs.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA.
| | | | - Amrita Mandal
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | - Alejandro Alvarez-Prats
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | | | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, USA
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22
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Enrich C, Lu A, Tebar F, Rentero C, Grewal T. Ca 2+ and Annexins - Emerging Players for Sensing and Transferring Cholesterol and Phosphoinositides via Membrane Contact Sites. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:393-438. [PMID: 36988890 DOI: 10.1007/978-3-031-21547-6_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Maintaining lipid composition diversity in membranes from different organelles is critical for numerous cellular processes. However, many lipids are synthesized in the endoplasmic reticulum (ER) and require delivery to other organelles. In this scenario, formation of membrane contact sites (MCS) between neighbouring organelles has emerged as a novel non-vesicular lipid transport mechanism. Dissecting the molecular composition of MCS identified phosphoinositides (PIs), cholesterol, scaffolding/tethering proteins as well as Ca2+ and Ca2+-binding proteins contributing to MCS functioning. Compelling evidence now exists for the shuttling of PIs and cholesterol across MCS, affecting their concentrations in distinct membrane domains and diverse roles in membrane trafficking. Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) at the plasma membrane (PM) not only controls endo-/exocytic membrane dynamics but is also critical in autophagy. Cholesterol is highly concentrated at the PM and enriched in recycling endosomes and Golgi membranes. MCS-mediated cholesterol transfer is intensely researched, identifying MCS dysfunction or altered MCS partnerships to correlate with de-regulated cellular cholesterol homeostasis and pathologies. Annexins, a conserved family of Ca2+-dependent phospholipid binding proteins, contribute to tethering and untethering events at MCS. In this chapter, we will discuss how Ca2+ homeostasis and annexins in the endocytic compartment affect the sensing and transfer of cholesterol and PIs across MCS.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cel⋅lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
- Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain.
| | - Albert Lu
- Departament de Biomedicina, Unitat de Biologia Cel⋅lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Francesc Tebar
- Departament de Biomedicina, Unitat de Biologia Cel⋅lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cel⋅lular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
- Facultat de Medicina i Ciències de la Salut, Universitat de Barcelona, Barcelona, Spain
| | - Thomas Grewal
- School of Pharmacy, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
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23
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Weber-Boyvat M, Kroll J, Trimbuch T, Olkkonen VM, Rosenmund C. The lipid transporter ORP2 regulates synaptic neurotransmitter release via two distinct mechanisms. Cell Rep 2022; 41:111882. [PMID: 36577376 DOI: 10.1016/j.celrep.2022.111882] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 08/26/2022] [Accepted: 12/02/2022] [Indexed: 12/28/2022] Open
Abstract
Cholesterol is crucial for neuronal synaptic transmission, assisting in the molecular and structural organization of lipid rafts, ion channels, and exocytic proteins. Although cholesterol absence was shown to result in impaired neurotransmission, how cholesterol locally traffics and its route of action are still under debate. Here, we characterized the lipid transfer protein ORP2 in murine hippocampal neurons. We show that ORP2 preferentially localizes to the presynapse. Loss of ORP2 reduces presynaptic cholesterol levels by 50%, coinciding with a profoundly reduced release probability, enhanced facilitation, and impaired presynaptic calcium influx. In addition, ORP2 plays a cholesterol-transport-independent role in regulating vesicle priming and spontaneous release, likely by competing with Munc18-1 in syntaxin1A binding. To conclude, we identified a dual function of ORP2 as a physiological modulator of the synaptic cholesterol content and a regulator of neuronal exocytosis.
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Affiliation(s)
- Marion Weber-Boyvat
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany.
| | - Jana Kroll
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Thorsten Trimbuch
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, 00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Christian Rosenmund
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany.
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24
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Overduin M, Tran A, Eekels DM, Overduin F, Kervin TA. Transmembrane Membrane Readers form a Novel Class of Proteins That Include Peripheral Phosphoinositide Recognition Domains and Viral Spikes. MEMBRANES 2022; 12:1161. [PMID: 36422153 PMCID: PMC9692390 DOI: 10.3390/membranes12111161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
Membrane proteins are broadly classified as transmembrane (TM) or peripheral, with functions that pertain to only a single bilayer at a given time. Here, we explicate a class of proteins that contain both transmembrane and peripheral domains, which we dub transmembrane membrane readers (TMMRs). Their transmembrane and peripheral elements anchor them to one bilayer and reversibly attach them to another section of bilayer, respectively, positioning them to tether and fuse membranes while recognizing signals such as phosphoinositides (PIs) and modifying lipid chemistries in proximity to their transmembrane domains. Here, we analyze full-length models from AlphaFold2 and Rosetta, as well as structures from nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, using the Membrane Optimal Docking Area (MODA) program to map their membrane-binding surfaces. Eukaryotic TMMRs include phospholipid-binding C1, C2, CRAL-TRIO, FYVE, GRAM, GTPase, MATH, PDZ, PH, PX, SMP, StART and WD domains within proteins including protrudin, sorting nexins and synaptotagmins. The spike proteins of SARS-CoV-2 as well as other viruses are also TMMRs, seeing as they are anchored into the viral membrane while mediating fusion with host cell membranes. As such, TMMRs have key roles in cell biology and membrane trafficking, and include drug targets for diseases such as COVID-19.
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Affiliation(s)
- Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Anh Tran
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | | | - Finn Overduin
- Institute of Nutritional Science, University of Potsdam, 14476 Potsdam, Germany
| | - Troy A. Kervin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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25
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Creating and sensing asymmetric lipid distributions throughout the cell. Emerg Top Life Sci 2022; 7:7-19. [PMID: 36373850 DOI: 10.1042/etls20220028] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/24/2022] [Accepted: 11/01/2022] [Indexed: 11/16/2022]
Abstract
A key feature of eukaryotic cells is the asymmetric distribution of lipids along their secretory pathway. Because of the biological significance of these asymmetries, it is crucial to define the mechanisms which create them. Extensive studies have led to the identification of lipid transfer proteins (LTPs) that work with lipid-synthesizing enzymes to carry lipids between two distinct membranes in a directional manner, and are thus able to create asymmetries in lipid distribution throughout the cell. These networks are often in contact sites where two organelle membranes are in close proximity for reasons we have only recently started to understand. A question is whether these networks transfer lipids en masse within the cells or adjust the lipid composition of organelle membranes. Finally, recent data have confirmed that some networks organized around LTPs do not generate lipid asymmetries between membranes but sense them and rectify the lipid content of the cell.
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26
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Wills RC, Hammond GRV. PI(4,5)P2: signaling the plasma membrane. Biochem J 2022; 479:2311-2325. [PMID: 36367756 PMCID: PMC9704524 DOI: 10.1042/bcj20220445] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/19/2022] [Accepted: 10/21/2022] [Indexed: 11/13/2022]
Abstract
In the almost 70 years since the first hints of its existence, the phosphoinositide, phosphatidyl-D-myo-inositol 4,5-bisphosphate has been found to be central in the biological regulation of plasma membrane (PM) function. Here, we provide an overview of the signaling, transport and structural roles the lipid plays at the cell surface in animal cells. These include being substrate for second messenger generation, direct modulation of receptors, control of membrane traffic, regulation of ion channels and transporters, and modulation of the cytoskeleton and cell polarity. We conclude by re-evaluating PI(4,5)P2's designation as a signaling molecule, instead proposing a cofactor role, enabling PM-selective function for many proteins.
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Affiliation(s)
- Rachel C. Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, U.S.A
| | - Gerald R. V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA, U.S.A
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27
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Chung GHC, Lorvellec M, Gissen P, Pichaud F, Burden JJ, Stefan CJ. The ultrastructural organization of endoplasmic reticulum-plasma membrane contacts is conserved in epithelial cells. Mol Biol Cell 2022; 33:ar113. [PMID: 35947498 PMCID: PMC9635291 DOI: 10.1091/mbc.e21-11-0534-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Contacts between the endoplasmic reticulum and the plasma membrane (ER-PM contacts) have important roles in membrane lipid and calcium dynamics, yet their organization in polarized epithelial cells has not been thoroughly described. Here we examine ER-PM contacts in hepatocytes in mouse liver using electron microscopy, providing the first comprehensive ultrastructural study of ER-PM contacts in a mammalian epithelial tissue. Our quantitative analyses reveal strikingly distinct ER-PM contact architectures spatially linked to apical, lateral, and basal PM domains. Notably, we find that an extensive network of ER-PM contacts exists at lateral PM domains that form intercellular junctions between hepatocytes. Moreover, the spatial organization of ER-PM contacts is conserved in epithelial spheroids, suggesting that ER-PM contacts may serve conserved roles in epithelial cell architecture. Consistent with this notion, we show that ORP5 activity at ER-PM contacts modulates the apical-basolateral aspect ratio in HepG2 cells. Thus ER-PM contacts have a conserved distribution and crucial roles in PM domain architecture across epithelial cell types.
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Affiliation(s)
- Gary Hong Chun Chung
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Maëlle Lorvellec
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Paul Gissen
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Franck Pichaud
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Jemima J Burden
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Christopher J Stefan
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
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28
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Palladino END, Bernas T, Green CD, Weigel C, Singh SK, Senkal CE, Martello A, Kennelly JP, Bieberich E, Tontonoz P, Ford DA, Milstien S, Eden ER, Spiegel S. Sphingosine kinases regulate ER contacts with late endocytic organelles and cholesterol trafficking. Proc Natl Acad Sci U S A 2022; 119:e2204396119. [PMID: 36122218 PMCID: PMC9522378 DOI: 10.1073/pnas.2204396119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 08/16/2022] [Indexed: 11/18/2022] Open
Abstract
Membrane contact sites (MCS), close membrane apposition between organelles, are platforms for interorganellar transfer of lipids including cholesterol, regulation of lipid homeostasis, and co-ordination of endocytic trafficking. Sphingosine kinases (SphKs), two isoenzymes that phosphorylate sphingosine to the bioactive sphingosine-1-phosphate (S1P), have been implicated in endocytic trafficking. However, the physiological functions of SphKs in regulation of membrane dynamics, lipid trafficking and MCS are not known. Here, we report that deletion of SphKs decreased S1P with concomitant increases in its precursors sphingosine and ceramide, and markedly reduced endoplasmic reticulum (ER) contacts with late endocytic organelles. Expression of enzymatically active SphK1, but not catalytically inactive, rescued the deficit of these MCS. Although free cholesterol accumulated in late endocytic organelles in SphK null cells, surprisingly however, cholesterol transport to the ER was not reduced. Importantly, deletion of SphKs promoted recruitment of the ER-resident cholesterol transfer protein Aster-B (also called GRAMD1B) to the plasma membrane (PM), consistent with higher accessible cholesterol and ceramide at the PM, to facilitate cholesterol transfer from the PM to the ER. In addition, ceramide enhanced in vitro binding of the Aster-B GRAM domain to phosphatidylserine and cholesterol liposomes. Our study revealed a previously unknown role for SphKs and sphingolipid metabolites in governing diverse MCS between the ER network and late endocytic organelles versus the PM to control the movement of cholesterol between distinct cell membranes.
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Affiliation(s)
- Elisa N. D. Palladino
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Tytus Bernas
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Christopher D. Green
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Cynthia Weigel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Sandeep K. Singh
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Can E. Senkal
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Andrea Martello
- UCL Institute of Ophthalmology, London EC1V 9EL, United Kingdom
| | - John P. Kennelly
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095
| | - Erhard Bieberich
- Department of Physiology, University of Kentucky and Veteran Affairs Medical Center, Lexington, KY 40536
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, University of California, Los Angeles, CA 90095
| | - David A. Ford
- Edward A. Doisy Department of Biochemistry and Molecular Biology, and Center for Cardiovascular Research, Saint Louis University School of Medicine, St. Louis, MO 63104
| | - Sheldon Milstien
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
| | - Emily R. Eden
- UCL Institute of Ophthalmology, London EC1V 9EL, United Kingdom
| | - Sarah Spiegel
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298
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29
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ORP5/8 and MIB/MICOS link ER-mitochondria and intra-mitochondrial contacts for non-vesicular transport of phosphatidylserine. Cell Rep 2022; 40:111364. [PMID: 36130504 DOI: 10.1016/j.celrep.2022.111364] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 05/10/2022] [Accepted: 08/24/2022] [Indexed: 11/24/2022] Open
Abstract
Mitochondria are dynamic organelles essential for cell survival whose structural and functional integrity rely on selective and regulated transport of lipids from/to the endoplasmic reticulum (ER) and across the mitochondrial intermembrane space. As they are not connected by vesicular transport, the exchange of lipids between ER and mitochondria occurs at membrane contact sites. However, the mechanisms and proteins involved in these processes are only beginning to emerge. Here, we show that the main physiological localization of the lipid transfer proteins ORP5 and ORP8 is at mitochondria-associated ER membrane (MAM) subdomains, physically linked to the mitochondrial intermembrane space bridging (MIB)/mitochondrial contact sites and cristae junction organizing system (MICOS) complexes that bridge the two mitochondrial membranes. We also show that ORP5/ORP8 mediate non-vesicular transport of phosphatidylserine (PS) lipids from the ER to mitochondria by cooperating with the MIB/MICOS complexes. Overall our study reveals a physical and functional link between ER-mitochondria contacts involved in lipid transfer and intra-mitochondrial membrane contacts maintained by the MIB/MICOS complexes.
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30
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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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31
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Guyard V, Monteiro-Cardoso VF, Omrane M, Sauvanet C, Houcine A, Boulogne C, Ben Mbarek K, Vitale N, Faklaris O, El Khallouki N, Thiam AR, Giordano F. ORP5 and ORP8 orchestrate lipid droplet biogenesis and maintenance at ER-mitochondria contact sites. J Cell Biol 2022; 221:e202112107. [PMID: 35969857 PMCID: PMC9375143 DOI: 10.1083/jcb.202112107] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 05/30/2022] [Accepted: 07/05/2022] [Indexed: 12/29/2022] Open
Abstract
Lipid droplets (LDs) are the primary organelles of lipid storage, buffering energy fluctuations of the cell. They store neutral lipids in their core that is surrounded by a protein-decorated phospholipid monolayer. LDs arise from the endoplasmic reticulum (ER). The ER protein seipin, localizing at ER-LD junctions, controls LD nucleation and growth. However, how LD biogenesis is spatially and temporally coordinated remains elusive. Here, we show that the lipid transfer proteins ORP5 and ORP8 control LD biogenesis at mitochondria-associated ER membrane (MAM) subdomains, enriched in phosphatidic acid. We found that ORP5/8 regulates seipin recruitment to these MAM-LD contacts, and their loss impairs LD biogenesis. Importantly, the integrity of ER-mitochondria contact sites is crucial for ORP5/8 function in regulating seipin-mediated LD biogenesis. Our study uncovers an unprecedented ORP5/8 role in orchestrating LD biogenesis and maturation at MAMs and brings novel insights into the metabolic crosstalk between mitochondria, ER, and LDs at the membrane contact sites.
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Affiliation(s)
- Valentin Guyard
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Vera Filipa Monteiro-Cardoso
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Mohyeddine Omrane
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Cécile Sauvanet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Audrey Houcine
- Institut Jacques Monod, CNRS, UMR7592, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Claire Boulogne
- Imagerie-Gif, Electron Microscopy Facility, Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Kalthoum Ben Mbarek
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Nicolas Vitale
- Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, UPR-321267000 Strasbourg, France
| | - Orestis Faklaris
- MRI, BioCampus Montpellier, CRBM, Univ. Montpellier, CNRS, Montpellier, France
| | - Naima El Khallouki
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l’École Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
- Inserm U1280, Gif-sur-Yvette, France
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32
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Gulyas G, Korzeniowski MK, Eugenio CEB, Vaca L, Kim YJ, Balla T. LIPID transfer proteins regulate store-operated calcium entry via control of plasma membrane phosphoinositides. Cell Calcium 2022; 106:102631. [PMID: 35853265 PMCID: PMC9444960 DOI: 10.1016/j.ceca.2022.102631] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 06/24/2022] [Accepted: 07/08/2022] [Indexed: 11/27/2022]
Abstract
The ER-resident proteins STIM1 together with the plasma membrane (PM)-localized Orai1 channels constitute the molecular components of the store-operated Ca2+ entry (SOCE) pathway. Prepositioning of STIM1 to the peripheral ER close to the PM ensures its efficient interaction with Orai1 upon a decrease in the ER luminal Ca2+ concentration. The C-terminal polybasic domain of STIM1 has been identified as mediating the interaction with PM phosphoinositides and hence positions the molecule to ER-PM contact sites. Here we show that STIM1 requires PM phosphatidylinositol 4-phosphate (PI4P) for efficient PM interaction. Accordingly, oxysterol binding protein related proteins (ORPs) that work at ER-PM junctions and consume PI4P gradients exert important control over the Ca2+ entry process. These studies reveal an important connection between non-vesicular lipid transport at ER-PM contact sites and regulation of ER Ca2+store refilling.
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Affiliation(s)
- Gergo Gulyas
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Marek K Korzeniowski
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, 20892, USA; Department of Anatomy, Physiology, and Genetics, Uniformed Services University, Bethesda, MD, USA
| | - Carlos Ernesto Bastián Eugenio
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, 20892, USA; Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico City DF, CP, 04510, USA
| | - Luis Vaca
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de Mexico City DF, CP, 04510, USA
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, MD, 20892, USA.
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33
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Taskinen JH, Ruhanen H, Matysik S, Käkelä R, Olkkonen VM. Global effects of pharmacologic inhibition of OSBP in human umbilical vein endothelial cells. Steroids 2022; 185:109053. [PMID: 35623602 DOI: 10.1016/j.steroids.2022.109053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/14/2022] [Accepted: 05/23/2022] [Indexed: 11/26/2022]
Abstract
Oxysterol-binding protein (OSBP) is a cholesterol/PI4P exchanger at contacts of the endoplasmic reticulum (ER) with trans-Golgi network (TGN) and endosomes. Several central endothelial cell (EC) functions depend on adequate cholesterol distribution in cellular membranes. Here we elucidated the effects of pharmacologic OSBP inhibition on the lipidome and transcriptome of human umbilical vein endothelial cells (HUVECs). OSBP was inhibited for 24 h with 25 nM Schweinfurthin G (SWG) or Orsaponin (OSW-1), followed by analyses of cellular cholesterol, 27-hydroxy-cholesterol, and triacylglycerol concentration, phosphatidylserine synthesis rate, the lipidome, as well as lipid droplet staining and western analysis of OSBP protein. Next-generation RNA sequencing of the SWG-treated and control HUVECs and angiogenesis assays were performed. Protein-normalized lipidomes of the inhibitor-treated cells revealed decreases in glycerophospholipids, the most pronounced effect being on phosphatidylserines and the rate of their synthesis, as well as increases in cholesteryl esters, triacylglycerols and lipid droplet number. Transcriptome analysis of SWG-treated cells suggested ER stress responses apparently caused by disturbed cholesterol exit from the ER, as indicated by suppression of cholesterol biosynthetic genes. OSBP was associated with the TGN in the absence of inhibitors and disappeared therefrom in inhibitor-treated cells in a time-dependent manner, coinciding with OSBP reduction on western blots. Prolonged treatment with SWG or OSW-1 inhibited angiogenesis in vitro. To conclude, inhibition of OSBP in primary endothelial cells induced multiple effects on the lipidome, transcriptome changes suggesting ER stress, and disruption of in vitro angiogenic capacity. Thus, OSBP is a crucial regulator of EC lipid homeostasis and angiogenic capacity.
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Affiliation(s)
- Juuso H Taskinen
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290 Helsinki, Finland.
| | - Hanna Ruhanen
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute of Life Science (HiLIFE) and Biocenter Finland, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 1, PO BOX 65, 00014 University of Helsinki, Finland.
| | - Silke Matysik
- Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
| | - Reijo Käkelä
- Helsinki University Lipidomics Unit (HiLIPID), Helsinki Institute of Life Science (HiLIFE) and Biocenter Finland, Molecular and Integrative Biosciences Research Programme, University of Helsinki, Viikinkaari 1, PO BOX 65, 00014 University of Helsinki, Finland.
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Tukholmankatu 8, 00290 Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Haartmaninkatu 8, 00290 Helsinki, Finland.
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34
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Depta L, Whitmarsh-Everiss T, Laraia L. Structure, function and small molecule modulation of intracellular sterol transport proteins. Bioorg Med Chem 2022; 68:116856. [PMID: 35716590 DOI: 10.1016/j.bmc.2022.116856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/23/2022] [Indexed: 11/02/2022]
Abstract
Intracellular sterol transport proteins (STPs) are crucial for maintaining cellular lipid homeostasis by regulating local sterol pools. Despite structural similarities in their sterol binding domains, STPs have different substrate specificities, intracellular localisation and biological functions. In this review, we highlight recent advances in the determination of STP structures and how this regulates their lipid specificities. Furthermore, we cover the important discoveries relating to the intracellular localisation of STPs, and the organelles between which lipid transport is carried out, giving rise to specific functions in health and disease. Finally, serendipitous and targeted efforts to identify small molecule modulators of STPs, as well as their ability to act as tool compounds and potential therapeutics, will be discussed.
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Affiliation(s)
- Laura Depta
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Thomas Whitmarsh-Everiss
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark
| | - Luca Laraia
- Department of Chemistry, Technical University of Denmark, Kemitorvet 207, 2800 Kgs Lyngby, Denmark.
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35
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Hammond GRV, Ricci MMC, Weckerly CC, Wills RC. An update on genetically encoded lipid biosensors. Mol Biol Cell 2022; 33:tp2. [PMID: 35420888 PMCID: PMC9282013 DOI: 10.1091/mbc.e21-07-0363] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/15/2022] [Accepted: 02/16/2022] [Indexed: 01/16/2023] Open
Abstract
Specific lipid species play central roles in cell biology. Their presence or enrichment in individual membranes can control properties or direct protein localization and/or activity. Therefore, probes to detect and observe these lipids in intact cells are essential tools in the cell biologist's freezer box. Herein, we discuss genetically encoded lipid biosensors, which can be expressed as fluorescent protein fusions to track lipids in living cells. We provide a state-of-the-art list of the most widely available and reliable biosensors and highlight new probes (circa 2018-2021). Notably, we focus on advances in biosensors for phosphatidylinositol, phosphatidic acid, and PI 3-kinase lipid products.
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Affiliation(s)
- Gerald R. V. Hammond
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Morgan M. C. Ricci
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Claire C. Weckerly
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Rachel C. Wills
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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36
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Zhu Y. Road to the discovery of HO-2's myristate binding activity. Cell Host Microbe 2022; 30:483-484. [PMID: 35421349 DOI: 10.1016/j.chom.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We discovered an unexpected new activity of a well-studied enzyme, heme oxygenase 2 (HO-2)-proof that an old dog can learn new tricks.
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Affiliation(s)
- Yiping Zhu
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY 14642, USA.
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37
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Byrne DJ, Garcia-Pardo ME, Cole NB, Batnasan B, Heneghan S, Sohail A, Blackstone C, O'Sullivan NC. Liver X receptor-agonist treatment rescues degeneration in a Drosophila model of hereditary spastic paraplegia. Acta Neuropathol Commun 2022; 10:40. [PMID: 35346366 PMCID: PMC8961908 DOI: 10.1186/s40478-022-01343-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 03/02/2022] [Indexed: 12/26/2022] Open
Abstract
Hereditary spastic paraplegias (HSPs) are a group of inherited, progressive neurodegenerative conditions characterised by prominent lower-limb spasticity and weakness, caused by a length-dependent degeneration of the longest corticospinal upper motor neurons. While more than 80 spastic paraplegia genes (SPGs) have been identified, many cases arise from mutations in genes encoding proteins which generate and maintain tubular endoplasmic reticulum (ER) membrane organisation. The ER-shaping proteins are essential for the health and survival of long motor neurons, however the mechanisms by which mutations in these genes cause the axonopathy observed in HSP have not been elucidated. To further develop our understanding of the ER-shaping proteins, this study outlines the generation of novel in vivo and in vitro models, using CRISPR/Cas9-mediated gene editing to knockout the ER-shaping protein ADP-ribosylation factor-like 6 interacting protein 1 (ARL6IP1), mutations in which give rise to the HSP subtype SPG61. Loss of Arl6IP1 in Drosophila results in progressive locomotor deficits, emulating a key aspect of HSP in patients. ARL6IP1 interacts with ER-shaping proteins and is required for regulating the organisation of ER tubules, particularly within long motor neuron axons. Unexpectedly, we identified physical and functional interactions between ARL6IP1 and the phospholipid transporter oxysterol-binding protein-related protein 8 in both human and Drosophila model systems, pointing to a conserved role for ARL6IP1 in lipid homeostasis. Furthermore, loss of Arl6IP1 from Drosophila neurons results in a cell non-autonomous accumulation of lipid droplets in axonal glia. Importantly, treatment with lipid regulating liver X receptor-agonists blocked lipid droplet accumulation, restored axonal ER organisation, and improved locomotor function in Arl6IP1 knockout Drosophila. Our findings indicate that disrupted lipid homeostasis contributes to neurodegeneration in HSP, identifying a potential novel therapeutic avenue for the treatment of this disorder.
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Affiliation(s)
- Dwayne J Byrne
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Nelson B Cole
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Belguun Batnasan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Sophia Heneghan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Anood Sohail
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
| | - Craig Blackstone
- Cell Biology Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, MA, 02129, USA
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Sciences, UCD Conway Institute, University College Dublin, Dublin 4, Ireland.
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Shi Q, Chen J, Zou X, Tang X. Intracellular Cholesterol Synthesis and Transport. Front Cell Dev Biol 2022; 10:819281. [PMID: 35386193 PMCID: PMC8978673 DOI: 10.3389/fcell.2022.819281] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Accepted: 02/01/2022] [Indexed: 12/18/2022] Open
Abstract
Cholesterol homeostasis is related to multiple diseases in humans, including cardiovascular disease, cancer, and neurodegenerative and hepatic diseases. The cholesterol levels in cells are balanced dynamically by uptake, biosynthesis, transport, distribution, esterification, and export. In this review, we focus on de novo cholesterol synthesis, cholesterol synthesis regulation, and intracellular cholesterol trafficking. In addition, the progression of lipid transfer proteins (LTPs) at multiple contact sites between organelles is considered.
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Affiliation(s)
- Qingyang Shi
- Center of Reproductive Medicine and Center of Prenatal Diagnosis, The First Hospital, Jilin University, Changchun, China
| | - Jiahuan Chen
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, China
| | - Xiaodong Zou
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, China
| | - Xiaochun Tang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, College of Animal Sciences, Jilin University, Changchun, China
- Chongqing Research Institute of Jilin University, Chongqing, China
- *Correspondence: Xiaochun Tang,
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39
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Dickson EJ. Phosphoinositide transport and metabolism at membrane contact sites. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159107. [PMID: 34995791 PMCID: PMC9662651 DOI: 10.1016/j.bbalip.2021.159107] [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: 06/30/2021] [Revised: 12/06/2021] [Accepted: 12/09/2021] [Indexed: 11/18/2022]
Abstract
Phosphoinositides are a family of signaling lipids that play a profound role in regulating protein function at the membrane-cytosol interface of all cellular membranes. Underscoring their importance, mutations or alterations in phosphoinositide metabolizing enzymes lead to host of developmental, neurodegenerative, and metabolic disorders that are devastating for human health. In addition to lipid enzymes, phosphoinositide metabolism is regulated and controlled at membrane contact sites (MCS). Regions of close opposition typically between the ER and other cellular membranes, MCS are non-vesicular lipid transport portals that engage in extensive communication to influence organelle homeostasis. This review focuses on lipid transport, specifically phosphoinositide lipid transport and metabolism at MCS.
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Affiliation(s)
- Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, United States of America.
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40
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Quon E, Nenadic A, Zaman MF, Johansen J, Beh CT. ER-PM membrane contact site regulation by yeast ORPs and membrane stress pathways. PLoS Genet 2022; 18:e1010106. [PMID: 35239652 PMCID: PMC8923467 DOI: 10.1371/journal.pgen.1010106] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/15/2022] [Accepted: 02/16/2022] [Indexed: 02/01/2023] Open
Abstract
In yeast, at least seven proteins (Ice2p, Ist2p, Scs2/22p, Tcb1-Tcb3p) affect cortical endoplasmic reticulum (ER) tethering and contact with the plasma membrane (PM). In Δ-super-tether (Δ-s-tether) cells that lack these tethers, cortical ER-PM association is all but gone. Yeast OSBP homologue (Osh) proteins are also implicated in membrane contact site (MCS) assembly, perhaps as subunits for multicomponent tethers, though their function at MCSs involves intermembrane lipid transfer. Paradoxically, when analyzed by fluorescence and electron microscopy, the elimination of the OSH gene family does not reduce cortical ER-PM association but dramatically increases it. In response to the inactivation of all Osh proteins, the yeast E-Syt (extended-synaptotagmin) homologue Tcb3p is post-transcriptionally upregulated thereby generating additional Tcb3p-dependent ER-PM MCSs for recruiting more cortical ER to the PM. Although the elimination of OSH genes and the deletion of ER-PM tether genes have divergent effects on cortical ER-PM association, both elicit the Environmental Stress Response (ESR). Through comparisons of transcriptomic profiles of cells lacking OSH genes or ER-PM tethers, changes in ESR expression are partially manifested through the induction of the HOG (high-osmolarity glycerol) PM stress pathway or the ER-specific UPR (unfolded protein response) pathway, respectively. Defects in either UPR or HOG pathways also increase ER-PM MCSs, and expression of extra “artificial ER-PM membrane staples” rescues growth of UPR mutants challenged with lethal ER stress. Transcriptome analysis of OSH and Δ-s-tether mutants also revealed dysregulation of inositol-dependent phospholipid gene expression, and the combined lethality of osh4Δ and Δ-s-tether mutations is suppressed by overexpression of the phosphatidic acid biosynthetic gene, DGK1. These findings establish that the Tcb3p tether is induced by ER and PM stresses and ER-PM MCSs augment responses to membrane stresses, which are integrated through the broader ESR pathway. Membrane contact sites (MCSs) between the two largest cellular membranes, the endoplasmic reticulum (ER) and the plasma membrane (PM), are regulatory interfaces for lipid synthesis and bidirectional transport. The yeast Osh protein family, which represents the seven yeast oxysterol-binding protein related proteins (ORPs), is implicated in MCS regulation and lipid transfer between membranes. Ironically, we find that when all Osh proteins eliminated, ER-PM association is not reduced but significantly increases. We hypothesized this increase is due to compensatory increases in levels of tether proteins that physically link the ER and PM. In fact, in response to inactivating Osh protein expression, amounts of the tether protein Tcb3 increase and more ER-PM MCSs are produced. By testing the genomic transcriptional responses to the elimination of OSH and ER-PM tether genes, we find these mutants disrupt phospholipid regulation and they elicit the Environmental Stress Response (ESR) pathway, which integrates many different responses needed for recovery after cellular stress. OSH and ER-PM tether genes affect specific stress response pathways that impact the PM and ER, respectively. Combining OSH and tether mutations results in cell lethality, but these cells survive by increased expression of a key phospholipid biosynthetic gene. Based on these results, we propose that OSH and ER-PM tether genes affect phospholipid regulation and protect the PM and ER through membrane stress responses integrated through the ESR pathway.
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Affiliation(s)
- Evan Quon
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Mohammad F. Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jesper Johansen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christopher T. Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, Canada
- * E-mail:
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41
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Gracie S, Sengupta N, Ferreira C, Pemberton J, Anderson I, Wang X, Rhodes L, Brown K, Balla T, Larson A. De novo loss-of-function variant in PTDSS1 is associated with developmental delay. Am J Med Genet A 2022; 188:1739-1745. [PMID: 35224839 DOI: 10.1002/ajmg.a.62695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/24/2022] [Accepted: 01/27/2022] [Indexed: 11/07/2022]
Abstract
Heterozygous de novo missense pathogenic variants in PTDSS1 that result in gain-of-function of phosphatidylserine synthase 1 are associated with Lenz-Majewski hyperostotic dwarfism (LMHD). We identified the novel heterozygous de novo variant p.(Leu137Phe) in PTDSS1 in a child with mild-to-moderate developmental delay. Skeletal survey revealed no evidence of LMHD in this patient. Functional assessment of the p.Leu137Phe variant was performed by overexpressing the mutant protein into HEK293 cells. Following C14 -serine labeling and TLC analysis of lipids, we observed that the p.(Leu137Phe) variant displayed no catalytic activity compared to the wild-type enzyme. We conclude that p.(Leu137Phe) variant has decreased enzymatic activity and that is likely to be the etiology of the patient's symptoms given the gene's constraint in the population. This is the first report of the clinical phenotype seen in an individual with a heterozygous loss-of-function variant in PTDSS1. This phenotype is distinct from LMHD, which results from gain-of-function pathogenic variants in the same gene. Evaluation of the neurodevelopmental phenotype of additional individuals with loss-of-function variants in PTDSS1 is indicated to determine the spectrum of associated phenotypes.
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Affiliation(s)
- Sara Gracie
- Department of Pediatrics, Section of Genetics and Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Nivedita Sengupta
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Carlos Ferreira
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Ilse Anderson
- University of Tennessee Graduate School of Medicine, Knoxville, Tennessee, USA
| | - Xin Wang
- GeneDx, Gaithersburg, Maryland, USA
| | | | - Kathleen Brown
- Department of Pediatrics, Section of Genetics and Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Austin Larson
- Department of Pediatrics, Section of Genetics and Children's Hospital Colorado, University of Colorado School of Medicine, Aurora, Colorado, USA
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42
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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43
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Olkkonen VM, Ikonen E. Cholesterol transport in the late endocytic pathway: Roles of ORP family proteins. J Steroid Biochem Mol Biol 2022; 216:106040. [PMID: 34864207 DOI: 10.1016/j.jsbmb.2021.106040] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 11/24/2021] [Accepted: 12/01/2021] [Indexed: 12/29/2022]
Abstract
Oxysterol-binding protein (OSBP) homologues, designated ORP or OSBPL proteins, constitute one of the largest families of intracellular lipid-binding/transfer proteins (LTP). This review summarizes the mounting evidence that several members of this family participate in the machinery facilitating cholesterol trafficking in the late endocytic pathway. There are indications that OSBP, besides acting as a cholesterol/phosphatidylinositol 4-phosphate (PI4P) exchanger at the endoplasmic reticulum (ER)-trans-Golgi network (TGN) membrane contact sites (MCS), also exchanges these lipids at ER-lysosome (Lys) contacts, increasing Lys cholesterol content. The long isoform of ORP1 (ORP1L), which also targets ER-late endosome (LE)/Lys MCS, has the capacity to mediate cholesterol transport either from ER to LE or in the opposite direction. Moreover, it regulates the motility, positioning and fusion of LE as well as autophagic flux. ORP2, the closest relative of ORP1, is mainly cytosolic, but also targets PI(4,5)P2-rich endosomal compartments. Our latest data suggest that ORP2 transfers cholesterol from LE to recycling endosomes (RE) in exchange for PI(4,5)P2, thus stimulating the recruitment of focal adhesion kinase (FAK) on the RE and cell adhesion. FAK activates phosphoinositide kinase on the RE to enhance PI(4,5)P2 synthesis. ORP2 in turn transfers PI(4,5)P2 from RE to LE, thus regulating LE tubule formation and transport activity.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
| | - Elina Ikonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland; Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
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44
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Islam MM, Hlushchenko I, Pfisterer SG. Low-Density Lipoprotein Internalization, Degradation and Receptor Recycling Along Membrane Contact Sites. Front Cell Dev Biol 2022; 10:826379. [PMID: 35141225 PMCID: PMC8819725 DOI: 10.3389/fcell.2022.826379] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 01/04/2022] [Indexed: 12/12/2022] Open
Abstract
Low-density lipoprotein (LDL) internalization, degradation, and receptor recycling is a fundamental process underlying hypercholesterolemia, a high blood cholesterol concentration, affecting more than 40% of the western population. Membrane contact sites influence endosomal dynamics, plasma membrane lipid composition, and cellular cholesterol distribution. However, if we focus on LDL-related trafficking events we mostly discuss them in an isolated fashion, without cellular context. It is our goal to change this perspective and to highlight that all steps from LDL internalization to receptor recycling are likely associated with dynamic membrane contact sites in which endosomes engage with the endoplasmic reticulum and other organelles.
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45
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Arora A, Taskinen JH, Olkkonen VM. Coordination of inter-organelle communication and lipid fluxes by OSBP-related proteins. Prog Lipid Res 2022; 86:101146. [PMID: 34999137 DOI: 10.1016/j.plipres.2022.101146] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 12/10/2021] [Accepted: 01/03/2022] [Indexed: 12/31/2022]
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute one of the largest families of lipid-binding/transfer proteins (LTPs) in eukaryotes. The current view is that many of them mediate inter-organelle lipid transfer over membrane contact sites (MCS). The transfer occurs in several cases in a 'counter-current' fashion: A lipid such as cholesterol or phosphatidylserine (PS) is transferred against its concentration gradient driven by transport of a phosphoinositide in the opposite direction. In this way ORPs are envisioned to maintain the distinct organelle lipid compositions, with impacts on multiple organelle functions. However, the functions of ORPs extend beyond lipid homeostasis to regulation of processes such as cell survival, proliferation and migration. Important expanding areas of mammalian ORP research include their roles in viral and bacterial infections, cancers, and neuronal function. The yeast OSBP homologue (Osh) proteins execute multifaceted functions in sterol and glycerophospholipid homeostasis, post-Golgi vesicle transport, phosphatidylinositol-4-phosphate, sphingolipid and target of rapamycin (TOR) signalling, and cell cycle control. These observations identify ORPs as lipid transporters and coordinators of signals with an unforeseen variety of cellular processes. Understanding their activities not only enlightens the biology of the living cell but also allows their employment as targets of new therapeutic approaches for disease.
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Affiliation(s)
- Amita Arora
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Juuso H Taskinen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
| | - Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, and Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland.
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46
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Kawasaki A, Sakai A, Nakanishi H, Hasegawa J, Taguchi T, Sasaki J, Arai H, Sasaki T, Igarashi M, Nakatsu F. PI4P/PS countertransport by ORP10 at ER-endosome membrane contact sites regulates endosome fission. J Cell Biol 2022; 221:212876. [PMID: 34817532 PMCID: PMC8624802 DOI: 10.1083/jcb.202103141] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/28/2021] [Accepted: 10/25/2021] [Indexed: 12/17/2022] Open
Abstract
Membrane contact sites (MCSs) serve as a zone for nonvesicular lipid transport by oxysterol-binding protein (OSBP)-related proteins (ORPs). ORPs mediate lipid countertransport, in which two distinct lipids are transported counterdirectionally. How such lipid countertransport controls specific biological functions, however, remains elusive. We report that lipid countertransport by ORP10 at ER–endosome MCSs regulates retrograde membrane trafficking. ORP10, together with ORP9 and VAP, formed ER–endosome MCSs in a phosphatidylinositol 4-phosphate (PI4P)-dependent manner. ORP10 exhibited a lipid exchange activity toward its ligands, PI4P and phosphatidylserine (PS), between liposomes in vitro, and between the ER and endosomes in situ. Cell biological analysis demonstrated that ORP10 supplies a pool of PS from the ER, in exchange for PI4P, to endosomes where the PS-binding protein EHD1 is recruited to facilitate endosome fission. Our study highlights a novel lipid exchange at ER–endosome MCSs as a nonenzymatic PI4P-to-PS conversion mechanism that organizes membrane remodeling during retrograde membrane trafficking.
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Affiliation(s)
- Asami Kawasaki
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Akiko Sakai
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Hiroki Nakanishi
- Graduate School of Medicine and Research Center for Biosignal, Akita University, Akita, Japan
| | - Junya Hasegawa
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tomohiko Taguchi
- Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Junko Sasaki
- Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Arai
- Laboratory of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Takehiko Sasaki
- Graduate School of Medicine and Research Center for Biosignal, Akita University, Akita, Japan.,Department of Biochemical Pathophysiology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Michihiro Igarashi
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
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47
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Zhao Y, Hou X, Chai J, Zhang Z, Xue X, Huang F, Liu J, Shi L, Liu Y. Stapled Liposomes Enhance Cross-Priming of Radio-Immunotherapy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2107161. [PMID: 34767279 DOI: 10.1002/adma.202107161] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/09/2021] [Indexed: 06/13/2023]
Abstract
The release of tumor-associated antigens (TAAs) and their cross-presentation in dendritic cells (DCs) are crucial for radio-immunotherapy. However, the irradiation resistance of tumor cells usually results in limited TAA generation and release. Importantly, TAAs internalized by DCs are easily degraded in lysosomes, resulting in unsatisfactory extent of TAA cross-presentation. Herein, an antigen-capturing stapled liposome (ACSL) with a robust structure and bioactive surface is developed. The ACSLs capture and transport TAAs from lysosomes to the cytoplasm in DCs, thereby enhancing TAA cross-presentation. l-arginine encapsulated in ACSLs induces robust T cell-dependent antitumor response and immune memory in 4T1 tumor-bearing mice after local irradiation, resulting in significant tumor suppression and an abscopal effect. Replacing l-arginine with radiosensitizers, photosensitizers, and photothermal agents may make ACSL a universal platform for the rapid development of various combinations of anticancer therapies.
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Affiliation(s)
- Yu Zhao
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Xiaoxue Hou
- Key Laboratory of Radiopharmacokinetics for Innovative Drugs, Chinese Academy of Medical Sciences, and Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Jingshan Chai
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Zhanzhan Zhang
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Xue Xue
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin, 300353, China
| | - Fan Huang
- Key Laboratory of Radiopharmacokinetics for Innovative Drugs, Chinese Academy of Medical Sciences, and Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Jianfeng Liu
- Key Laboratory of Radiopharmacokinetics for Innovative Drugs, Chinese Academy of Medical Sciences, and Institute of Radiation Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, 300192, China
| | - Linqi Shi
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
| | - Yang Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Functional Polymer Materials of Ministry of Education, College of Chemistry, Frontiers Science Center for New Organic Matter, Nankai University, Tianjin, 300071, China
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Components of the phosphatidylserine endoplasmic reticulum to plasma membrane transport mechanism as targets for KRAS inhibition in pancreatic cancer. Proc Natl Acad Sci U S A 2021; 118:2114126118. [PMID: 34903667 DOI: 10.1073/pnas.2114126118] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/01/2021] [Indexed: 12/19/2022] Open
Abstract
KRAS is mutated in 90% of human pancreatic ductal adenocarcinomas (PDACs). To function, KRAS must localize to the plasma membrane (PM) via a C-terminal membrane anchor that specifically engages phosphatidylserine (PtdSer). This anchor-binding specificity renders KRAS-PM localization and signaling capacity critically dependent on PM PtdSer content. We now show that the PtdSer lipid transport proteins, ORP5 and ORP8, which are essential for maintaining PM PtdSer levels and hence KRAS PM localization, are required for KRAS oncogenesis. Knockdown of either protein, separately or simultaneously, abrogated growth of KRAS-mutant but not KRAS-wild-type pancreatic cancer cell xenografts. ORP5 or ORP8 knockout also abrogated tumor growth in an immune-competent orthotopic pancreatic cancer mouse model. Analysis of human datasets revealed that all components of this PtdSer transport mechanism, including the PM-localized EFR3A-PI4KIIIα complex that generates phosphatidylinositol-4-phosphate (PI4P), and endoplasmic reticulum (ER)-localized SAC1 phosphatase that hydrolyzes counter transported PI4P, are significantly up-regulated in pancreatic tumors compared to normal tissue. Taken together, these results support targeting PI4KIIIα in KRAS-mutant cancers to deplete the PM-to-ER PI4P gradient, reducing PM PtdSer content. We therefore repurposed the US Food and Drug Administration-approved hepatitis C antiviral agent, simeprevir, as a PI4KIIIα inhibitor In a PDAC setting. Simeprevir potently mislocalized KRAS from the PM, reduced the clonogenic potential of pancreatic cancer cell lines in vitro, and abrogated the growth of KRAS-dependent tumors in vivo with enhanced efficacy when combined with MAPK and PI3K inhibitors. We conclude that the cellular ER-to-PM PtdSer transport mechanism is essential for KRAS PM localization and oncogenesis and is accessible to therapeutic intervention.
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Ikhlef S, Lipp NF, Delfosse V, Fuggetta N, Bourguet W, Magdeleine M, Drin G. Functional analyses of phosphatidylserine/PI(4)P exchangers with diverse lipid species and membrane contexts reveal unanticipated rules on lipid transfer. BMC Biol 2021; 19:248. [PMID: 34801011 PMCID: PMC8606082 DOI: 10.1186/s12915-021-01183-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 11/04/2021] [Indexed: 11/14/2022] Open
Abstract
Background Lipid species are accurately distributed in the eukaryotic cell so that organelle and plasma membranes have an adequate lipid composition to support numerous cellular functions. In the plasma membrane, a precise regulation of the level of lipids such as phosphatidylserine, PI(4)P, and PI(4,5)P2, is critical for maintaining the signaling competence of the cell. Several lipid transfer proteins of the ORP/Osh family contribute to this fine-tuning by delivering PS, synthesized in the endoplasmic reticulum, to the plasma membrane in exchange for PI(4)P. To get insights into the role of these PS/PI(4)P exchangers in regulating plasma membrane features, we question how they selectively recognize and transfer lipid ligands with different acyl chains, whether these proteins exchange PS exclusively for PI(4)P or additionally for PI(4,5)P2, and how sterol abundance in the plasma membrane impacts their activity. Results We measured in vitro how the yeast Osh6p and human ORP8 transported PS and PI(4)P subspecies of diverse length and unsaturation degree between membranes by fluorescence-based assays. We established that the exchange activity of Osh6p and ORP8 strongly depends on whether these ligands are saturated or not, and is high with representative cellular PS and PI(4)P subspecies. Unexpectedly, we found that the speed at which these proteins individually transfer lipid ligands between membranes is inversely related to their affinity for them and that high-affinity ligands must be exchanged to be transferred more rapidly. Next we determined that Osh6p and ORP8 cannot use PI(4,5)P2 for exchange processes, because it is a low-affinity ligand, and do not transfer more PS into sterol-rich membranes. Conclusions Our study provides new insights into PS/PI(4)P exchangers by indicating the degree to which they can regulate the acyl chain composition of the PM, and how they control PM phosphoinositide levels. Moreover, we establish general rules on how the activity of lipid transfer proteins relates to their affinity for ligands. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01183-1.
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Affiliation(s)
- Souade Ikhlef
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560, Valbonne, France
| | - Nicolas-Frédéric Lipp
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560, Valbonne, France.,Current position: Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Vanessa Delfosse
- Centre de Biologie Structurale, INSERM, CNRS, Université de Montpellier, Montpellier, France
| | - Nicolas Fuggetta
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560, Valbonne, France
| | - William Bourguet
- Centre de Biologie Structurale, INSERM, CNRS, Université de Montpellier, Montpellier, France
| | - Maud Magdeleine
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560, Valbonne, France
| | - Guillaume Drin
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560, Valbonne, France.
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Eisenreichova A, Różycki B, Boura E, Humpolickova J. Osh6 Revisited: Control of PS Transport by the Concerted Actions of PI4P and Sac1 Phosphatase. Front Mol Biosci 2021; 8:747601. [PMID: 34712698 PMCID: PMC8546167 DOI: 10.3389/fmolb.2021.747601] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 09/08/2021] [Indexed: 12/03/2022] Open
Abstract
Osh6, a member of the oxysterol-binding protein-related protein (ORP) family, is a lipid transport protein that is involved in the transport of phosphatidylserine (PS) between the endoplasmic reticulum (ER) and the plasma membrane (PM). We used a biophysical approach to characterize its transport mechanism in detail. We examined the transport of all potential ligands of Osh6. PI4P and PS are the best described lipid cargo molecules; in addition, we showed that PIP2 can be transported by Osh6 as well. So far, it was the exchange between the two cargo molecules, PS and PI4P, in the lipid-binding pocket of Osh6 that was considered an essential driving force for the PS transport. However, we showed that Osh6 can efficiently transport PS along the gradient without the help of PI4P and that PI4P inhibits the PS transport along its gradient. This observation highlights that the exchange between PS and PI4P is indeed crucial, but PI4P bound to the protein rather than intensifying the PS transport suppresses it. We considered this to be important for the transport directionality as it prevents PS from returning back from the PM where its concentration is high to the ER where it is synthesized. Our results also highlighted the importance of the ER resident Sac1 phosphatase that enables the PS transport and ensures its directionality by PI4P consumption. Furthermore, we showed that the Sac1 activity is regulated by the negative charge of the membrane that can be provided by PS or PI anions in the case of the ER membrane.
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Affiliation(s)
- Andrea Eisenreichova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Bartosz Różycki
- Institute of Physics, Polish Academy of Sciences, Warsaw, Poland
| | - Evzen Boura
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
| | - Jana Humpolickova
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czechia
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