1
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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 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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2
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Wang Y, Yang J. ER-organelle contacts: A signaling hub for neurological diseases. Pharmacol Res 2024; 203:107149. [PMID: 38518830 DOI: 10.1016/j.phrs.2024.107149] [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: 11/28/2023] [Revised: 03/07/2024] [Accepted: 03/19/2024] [Indexed: 03/24/2024]
Abstract
Neuronal health is closely linked to the homeostasis of intracellular organelles, and organelle dysfunction affects the pathological progression of neurological diseases. In contrast to isolated cellular compartments, a growing number of studies have found that organelles are largely interdependent structures capable of communicating through membrane contact sites (MCSs). MCSs have been identified as key pathways mediating inter-organelle communication crosstalk in neurons, and their alterations have been linked to neurological disease pathology. The endoplasmic reticulum (ER) is a membrane-bound organelle capable of forming an extensive network of pools and tubules with important physiological functions within neurons. There are multiple MCSs between the ER and other organelles and the plasma membrane (PM), which regulate a variety of cellular processes. In this review, we focus on ER-organelle MCSs and their role in a variety of neurological diseases. We compared the biological effects between different tethering proteins and the effects of their respective disease counterparts. We also discuss how altered ER-organelle contacts may affect disease pathogenesis. Therefore, understanding the molecular mechanisms of ER-organelle MCSs in neuronal homeostasis will lay the foundation for the development of new therapies targeting ER-organelle contacts.
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Affiliation(s)
- Yunli Wang
- Key Laboratory of Environmental Stress and Chronic Disease Control & Prevention (China Medical University), Ministry of Education, PR China; Department of Toxicology, School of Public Health, China Medical University, Shenyang 110122, PR China
| | - Jinghua Yang
- Key Laboratory of Environmental Stress and Chronic Disease Control & Prevention (China Medical University), Ministry of Education, PR China; Department of Toxicology, School of Public Health, China Medical University, Shenyang 110122, PR China.
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3
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Saukko-Paavola AJ, Klemm RW. Remodelling of mitochondrial function by import of specific lipids at multiple membrane-contact sites. FEBS Lett 2024; 598:1274-1291. [PMID: 38311340 DOI: 10.1002/1873-3468.14813] [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: 11/29/2023] [Revised: 12/14/2023] [Accepted: 12/28/2023] [Indexed: 02/08/2024]
Abstract
Organelles form physical and functional contact between each other to exchange information, metabolic intermediates, and signaling molecules. Tethering factors and contact site complexes bring partnering organelles into close spatial proximity to establish membrane contact sites (MCSs), which specialize in unique functions like lipid transport or Ca2+ signaling. Here, we discuss how MCSs form dynamic platforms that are important for lipid metabolism. We provide a perspective on how import of specific lipids from the ER and other organelles may contribute to remodeling of mitochondria during nutrient starvation. We speculate that mitochondrial adaptation is achieved by connecting several compartments into a highly dynamic organelle network. The lipid droplet appears to be a central hub in coordinating the function of these organelle neighborhoods.
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Affiliation(s)
| | - Robin W Klemm
- Department of Physiology, Anatomy and Genetics, University of Oxford, UK
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4
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Wölk M, Fedorova M. The lipid droplet lipidome. FEBS Lett 2024; 598:1215-1225. [PMID: 38604996 DOI: 10.1002/1873-3468.14874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/18/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Lipid droplets (LDs) are intracellular organelles with a hydrophobic core formed by neutral lipids surrounded by a phospholipid monolayer harboring a variety of regulatory and enzymatically active proteins. Over the last few decades, our understanding of LD biology has evolved significantly. Nowadays, LDs are appreciated not just as passive energy storage units, but rather as active players in the regulation of lipid metabolism and quality control machineries. To fulfill their functions in controlling cellular metabolic states, LDs need to be highly dynamic and responsive organelles. A large body of evidence supports a dynamic nature of the LD proteome and its contact sites with other organelles. However, much less is known about the lipidome of LDs. Numerous examples clearly indicate the intrinsic link between LD lipids and proteins, calling for a deeper characterization of the LD lipidome in various physiological and pathological settings. Here, we reviewed the current state of knowledge in the field of the LD lipidome, providing a brief overview of the lipid classes and their molecular species present within the neutral core and phospholipid monolayer.
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Affiliation(s)
- Michele Wölk
- Center of Membrane Biochemistry and Lipid Research, University Hospital Carl Gustav Carus and Faculty of Medicine of TU Dresden, Germany
| | - Maria Fedorova
- Center of Membrane Biochemistry and Lipid Research, University Hospital Carl Gustav Carus and Faculty of Medicine of TU Dresden, Germany
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5
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Coates HW, Nguyen TB, Du X, Olzomer EM, Farrell R, Byrne FL, Yang H, Brown AJ. The constitutively active form of a key cholesterol synthesis enzyme is lipid droplet-localized and upregulated in endometrial cancer tissues. J Biol Chem 2024; 300:107232. [PMID: 38537696 PMCID: PMC11061744 DOI: 10.1016/j.jbc.2024.107232] [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: 02/29/2024] [Accepted: 03/18/2024] [Indexed: 04/26/2024] Open
Abstract
Cholesterol is essential for both normal cell viability and cancer cell proliferation. Aberrant activity of squalene monooxygenase (SM, also known as squalene epoxidase), the rate-limiting enzyme of the committed cholesterol synthesis pathway, is accordingly implicated in a growing list of cancers. We previously reported that hypoxia triggers the truncation of SM to a constitutively active form, thus preserving sterol synthesis during oxygen shortfalls. Here, we show SM truncation is upregulated and correlates with the magnitude of hypoxia in endometrial cancer tissues, supporting the in vivo relevance of our earlier work. To further investigate the pathophysiological consequences of SM truncation, we examined its lipid droplet-localized pool using complementary immunofluorescence and cell fractionation approaches and found that it exclusively comprises the truncated enzyme. This partitioning is facilitated by the loss of an endoplasmic reticulum-embedded region at the SM N terminus, whereas the catalytic domain containing membrane-associated C-terminal helices is spared. Moreover, we determined multiple amphipathic helices contribute to the lipid droplet localization of truncated SM. Taken together, our results expand on the striking differences between the two forms of SM and suggest upregulated truncation may contribute to SM-related oncogenesis.
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Affiliation(s)
- Hudson W Coates
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Tina B Nguyen
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Ellen M Olzomer
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Rhonda Farrell
- Chris O'Brien Lifehouse, Camperdown, New South Wales, Australia; Prince of Wales Private Hospital, Randwick, New South Wales, Australia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, New South Wales, Australia.
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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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Mathiowetz AJ, Olzmann JA. Lipid droplets and cellular lipid flux. Nat Cell Biol 2024; 26:331-345. [PMID: 38454048 DOI: 10.1038/s41556-024-01364-4] [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: 07/30/2023] [Accepted: 01/24/2024] [Indexed: 03/09/2024]
Abstract
Lipid droplets are dynamic organelles that store neutral lipids, serve the metabolic needs of cells, and sequester lipids to prevent lipotoxicity and membrane damage. Here we review the current understanding of the mechanisms of lipid droplet biogenesis and turnover, the transfer of lipids and metabolites at membrane contact sites, and the role of lipid droplets in regulating fatty acid flux in lipotoxicity and cell death.
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Affiliation(s)
- Alyssa J Mathiowetz
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA
| | - James A Olzmann
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, Berkeley, CA, USA.
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA, USA.
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8
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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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9
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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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10
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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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11
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Deng Y, Zhu H, Wang Y, Dong Y, Du J, Yu Q, Li M. The Endoplasmic Reticulum-Plasma Membrane Tethering Protein Ice2 Controls Lipid Droplet Size via the Regulation of Phosphatidylcholine in Candida albicans. J Fungi (Basel) 2024; 10:87. [PMID: 38276033 PMCID: PMC10817647 DOI: 10.3390/jof10010087] [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: 11/23/2023] [Revised: 01/13/2024] [Accepted: 01/17/2024] [Indexed: 01/27/2024] Open
Abstract
Lipid droplets (LDs) are intracellular organelles that play important roles in cellular lipid metabolism; they change their sizes and numbers in response to both intracellular and extracellular signals. Changes in LD size reflect lipid synthesis and degradation and affect many cellular activities, including energy supply and membrane synthesis. Here, we focused on the function of the endoplasmic reticulum-plasma membrane tethering protein Ice2 in LD dynamics in the fungal pathogen Candida albicans (C. albicans). Nile red staining and size quantification showed that the LD size increased in the ice2Δ/Δ mutant, indicating the critical role of Ice2 in the regulation of LD dynamics. A lipid content analysis further demonstrated that the mutant had lower phosphatidylcholine levels. As revealed with GFP labeling and fluorescence microscopy, the methyltransferase Cho2, which is involved in phosphatidylcholine synthesis, had poorer localization in the plasma membrane in the mutant than in the wild-type strain. Interestingly, the addition of the phosphatidylcholine precursor choline led to the recovery of normal-sized LDs in the mutant. These results indicated that Ice2 regulates LD size by controlling intracellular phosphatidylcholine levels and that endoplasmic reticulum-plasma membrane tethering proteins play a role in lipid metabolism regulation in C. albicans. This study provides significant findings for further investigation of the lipid metabolism in fungi.
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Affiliation(s)
| | | | | | | | | | | | - Mingchun Li
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin 300071, China; (Y.D.); (H.Z.); (Y.W.); (Y.D.); (J.D.)
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12
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Zhang C, Ye M, Melikov K, Yang D, Dias do Vale G, McDonald J, Eckert K, Lin MJ, Zeng X. CLSTN3B enhances adipocyte lipid droplet structure and function via endoplasmic reticulum contact. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.20.576491. [PMID: 38293096 PMCID: PMC10827225 DOI: 10.1101/2024.01.20.576491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Interorganelle contacts facilitate material exchanges and sustain the structural and functional integrity of organelles. Lipid droplets (LDs) of adipocytes are responsible for energy storage and mobilization responding to body needs. LD biogenesis defects compromise the lipid-storing capacity of adipocytes, resulting in ectopic lipid deposition and metabolic disorders, yet how the uniquely large LDs in adipocytes attain structural and functional maturation is incompletely understood. Here we show that the mammalian adipocyte-specific protein CLSTN3B is crucial for adipocyte LD maturation. CLSTN3B employs an arginine-rich segment to promote extensive contact and hemifusion-like structure formation between the endoplasmic reticulum (ER) and LD, allowing ER-to-LD phospholipid diffusion during LD expansion. CLSTN3B ablation results in reduced LD surface phospholipid density, increased turnover of LD-surface proteins, and impaired LD functions. Our results establish the central role of CLSTN3B in the adipocyte-specific LD maturation pathway that enhances lipid storage and maintenance of metabolic health under caloric overload.
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Affiliation(s)
- Chuanhai Zhang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX
| | - Mengchen Ye
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA
| | - Kamran Melikov
- Section on Membrane Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Dengbao Yang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX
| | | | - Jeffrey McDonald
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX
| | - Kaitlyn Eckert
- Center for Human Nutrition, UT Southwestern Medical Center, Dallas, TX
| | - Mei-Jung Lin
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX
| | - Xing Zeng
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX
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13
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Wan N, Hong Z, Parson MAH, Korfhage JL, Burke JE, Melia TJ, Reinisch KM. Spartin-mediated lipid transfer facilitates lipid droplet turnover. Proc Natl Acad Sci U S A 2024; 121:e2314093121. [PMID: 38190532 PMCID: PMC10801920 DOI: 10.1073/pnas.2314093121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 12/01/2023] [Indexed: 01/10/2024] Open
Abstract
Lipid droplets (LDs) are organelles critical for energy storage and membrane lipid homeostasis, whose number and size are carefully regulated in response to cellular conditions. The molecular mechanisms underlying lipid droplet biogenesis and degradation, however, are not well understood. The Troyer syndrome protein spartin (SPG20) supports LD delivery to autophagosomes for turnover via lipophagy. Here, we characterize spartin as a lipid transfer protein whose transfer ability is required for LD degradation. Spartin copurifies with phospholipids and neutral lipids from cells and transfers phospholipids in vitro via its senescence domain. A senescence domain truncation that impairs lipid transfer in vitro also impairs LD turnover in cells while not affecting spartin association with either LDs or autophagosomes, supporting that spartin's lipid transfer ability is physiologically relevant. Our data indicate a role for spartin-mediated lipid transfer in LD turnover.
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Affiliation(s)
- Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Zhouping Hong
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Matthew A. H. Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BCV8W2Y2, Canada
| | - Justin L. Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - John E. Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BCV8W2Y2, Canada
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BCV6T 1Z3, Canada
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
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14
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Zhong Y, Levine TP. Spartin is a Lipid Transfer Protein That Facilitates Lipid Droplet Turnover. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2024; 7:25152564241255782. [PMID: 38808280 PMCID: PMC11131387 DOI: 10.1177/25152564241255782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/30/2024]
Abstract
One means by which cells reutilize neutral lipids stored in lipid droplets is to degrade them by autophagy. This process involves spartin, mutations of which cause the rare inherited disorder Troyer syndrome (or spastic paraplegia-20, SPG20). A recently published paper from the team led by Karin Reinsich (Yale) suggests that the molecular function of spartin and its unique highly conserved "senescence" domain is as a lipid transfer protein. Spartin binds to and transfers all lipid species found in lipid droplets, from phospholipids to triglycerides and sterol esters. This lipid transfer activity correlates with spartin's ability to sustain lipid droplet turnover. The senescence domain poses an intriguing question around the wide range of its cargoes, but intriguingly it has yet to yield up its secrets because attempts at crystallization failed and AlphaFold's prediction is unconvincing.
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Affiliation(s)
- Yaoyang Zhong
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Tim P. Levine
- UCL Institute of Ophthalmology, University College London, London, UK
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15
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Wan N, Hong Z, Parson MAH, Korfhage J, Burke JE, Melia TJ, Reinisch KM. Spartin-mediated lipid transfer facilitates lipid droplet turnover. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569220. [PMID: 38076959 PMCID: PMC10705495 DOI: 10.1101/2023.11.29.569220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Lipid droplets (LDs) are organelles critical for energy storage and membrane lipid homeostasis, whose number and size are carefully regulated in response to cellular conditions. The molecular mechanisms underlying lipid droplet biogenesis and degradation, however, are not well understood. The Troyer syndrome protein spartin (SPG20) supports LD delivery to autophagosomes for turnover via lipophagy. Here, we characterize spartin as a lipid transfer protein whose transfer ability is required for LD degradation. Spartin co-purifies with phospholipids and neutral lipids from cells and transfers phospholipids in vitro via its senescence domain. A senescence domain truncation that impairs lipid transfer in vitro also impairs LD turnover in cells while not affecting spartin association with either LDs or autophagosomes, supporting that spartin's lipid transfer ability is physiologically relevant. Our data indicate a role for spartin-mediated lipid transfer in LD turnover.
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Affiliation(s)
- Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Zhouping Hong
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Matthew A. H. Parson
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W2Y2
| | - Justin Korfhage
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - John E. Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8W2Y2
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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16
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Al Mamun MA, Reza MA, Islam MS. Identification of novel proteins regulating lipid droplet biogenesis in filamentous fungi. Mol Microbiol 2023; 120:702-722. [PMID: 37748926 DOI: 10.1111/mmi.15170] [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: 03/02/2023] [Revised: 09/06/2023] [Accepted: 09/11/2023] [Indexed: 09/27/2023]
Abstract
Lipid droplets (LDs) are storage organelles for neutral lipids which are critical for lipid homeostasis. Current knowledge of fungal LD biogenesis is largely limited to budding yeast, while LD regulation in multinucleated filamentous fungi which exhibit considerable metabolic activity remains unexplored. In this study, 19 LD-associated proteins were identified in the multinucleated species Aspergillus oryzae using a colocalization screening of a previously established enhanced green fluorescent protein (EGFP) fusion library. Functional screening identified 12 lipid droplet-regulating (LDR) proteins whose loss of function resulted in irregular LD biogenesis, particularly in terms of LD number and size. Bioinformatics analysis, targeted mutagenesis, and microscopy revealed four LDR proteins that localize to LD via the putative amphipathic helices (AHs). Further analysis revealed that LdrA with an Opi1 domain is essential for cytoplasmic and nuclear LD biogenesis involving a novel AH. Phylogenetic analysis demonstrated that the patterns of gene evolution were predominantly based on gene duplication. Our study identified a set of novel proteins involved in the regulation of LD biogenesis, providing unique molecular and evolutionary insights into fungal lipid storage.
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Affiliation(s)
- Md Abdulla Al Mamun
- Department of Biotechnology, The University of Tokyo, Tokyo, Japan
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
- Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - M Abu Reza
- Department of Genetic Engineering and Biotechnology, University of Rajshahi, Rajshahi, Bangladesh
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17
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Pu M, Zheng W, Zhang H, Wan W, Peng C, Chen X, Liu X, Xu Z, Zhou T, Sun Q, Neculai D, Liu W. ORP8 acts as a lipophagy receptor to mediate lipid droplet turnover. Protein Cell 2023; 14:653-667. [PMID: 37707322 PMCID: PMC10501187 DOI: 10.1093/procel/pwac063] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 11/22/2022] [Indexed: 09/15/2023] Open
Abstract
Lipophagy, the selective engulfment of lipid droplets (LDs) by autophagosomes for lysosomal degradation, is critical to lipid and energy homeostasis. Here we show that the lipid transfer protein ORP8 is located on LDs and mediates the encapsulation of LDs by autophagosomal membranes. This function of ORP8 is independent of its lipid transporter activity and is achieved through direct interaction with phagophore-anchored LC3/GABARAPs. Upon lipophagy induction, ORP8 has increased localization on LDs and is phosphorylated by AMPK, thereby enhancing its affinity for LC3/GABARAPs. Deletion of ORP8 or interruption of ORP8-LC3/GABARAP interaction results in accumulation of LDs and increased intracellular triglyceride. Overexpression of ORP8 alleviates LD and triglyceride deposition in the liver of ob/ob mice, and Osbpl8-/- mice exhibit liver lipid clearance defects. Our results suggest that ORP8 is a lipophagy receptor that plays a key role in cellular lipid metabolism.
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Affiliation(s)
- Maomao Pu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wenhui Zheng
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Hongtao Zhang
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wei Wan
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Chao Peng
- National Center for Protein Science Shanghai, Institute of Biochemistry and Cell Biology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xuebo Chen
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Xinchang Liu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Zizhen Xu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Tianhua Zhou
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Qiming Sun
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Dante Neculai
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
| | - Wei Liu
- Metabolic Medicine Center, International Institutes of Medicine, the Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu 322000, China
- Joint Institute of Genetics and Genomics Medicine between Zhejiang University and University of Toronto, Hangzhou 310058, China
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18
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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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19
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Zadoorian A, Du X, Yang H. Lipid droplet biogenesis and functions in health and disease. Nat Rev Endocrinol 2023:10.1038/s41574-023-00845-0. [PMID: 37221402 DOI: 10.1038/s41574-023-00845-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/25/2023] [Indexed: 05/25/2023]
Abstract
Ubiquitous yet unique, lipid droplets are intracellular organelles that are increasingly being recognized for their versatility beyond energy storage. Advances uncovering the intricacies of their biogenesis and the diversity of their physiological and pathological roles have yielded new insights into lipid droplet biology. Despite these insights, the mechanisms governing the biogenesis and functions of lipid droplets remain incompletely understood. Moreover, the causal relationship between the biogenesis and function of lipid droplets and human diseases is poorly resolved. Here, we provide an update on the current understanding of the biogenesis and functions of lipid droplets in health and disease, highlighting a key role for lipid droplet biogenesis in alleviating cellular stresses. We also discuss therapeutic strategies of targeting lipid droplet biogenesis, growth or degradation that could be applied in the future to common diseases, such as cancer, hepatic steatosis and viral infection.
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Affiliation(s)
- Armella Zadoorian
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Ximing Du
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia
| | - Hongyuan Yang
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, Australia.
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20
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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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21
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Liu X, Li C, Chen Y, Xue Z, Miao J, Liu X. Untargeted lipidomics reveals lipid metabolism disorders induced by oxathiapiprolin in Phytophthora sojae. PEST MANAGEMENT SCIENCE 2023; 79:1593-1603. [PMID: 36562252 DOI: 10.1002/ps.7334] [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: 11/02/2022] [Revised: 12/12/2022] [Accepted: 12/23/2022] [Indexed: 06/17/2023]
Abstract
BACKGROUND Oxathiapiprolin, an oxysterol-binding protein inhibitor (OSBPI), shows unexceptionable inhibitory activity against plant pathogenic oomycetes. FRAC (Fungicide Resistance Action Committee) classifies it into the mode of action group F9 (lipid homeostasis and transfer/storage), but very little is known about the lipid metabolism of oomycete pathogens when subjected to oxathiapiprolin. RESULTS In this study, seven lipid categories and 1435 lipid molecules were identified in Phytophthora sojae, among which glycerolipids, glycerophospholipids, and sphingolipids account for 30.10%, 50.59%, and 7.28%, respectively. These lipids were categorized into 31 subclasses, which varied to different extents when treated with oxathiapiprolin. A total of 11 lipid subclasses showed significant changes. Among them, 10 lipid subclasses, lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), phosphatidylcholine (PC), phosphatidylserine (PS), ceramide (Cer), triglyceride (TG), (o-acyl)-1-hydroxy fatty acid, diglycosylceramide, sphingoshine (So), and sitosterol ester, were significantly up-regulated, while digalactosyldiacylglycerol was the only lipid that was significantly down-regulated by a factor of almost three. These lipid molecules were further analyzed at the lipid species level. A total of 542 species were significantly altered when treated with oxathiapiprolin, including 212 glycerolipids [186 TG and 26 diglycerides (DG)], 167 glycerophospholipids (38 PC, 15 LPC, 19 LPE, seven PS, etc.), 156 sphingolipids (146 Cer, four So, etc.), and some other lipid molecules. Finally, from the orthogonal partial least-squares discrimination analysis model, variable importance for the projection score analysis showed that Cer, TG, and some glycerophospholipids contribute to the metabolic disorder when subjected to oxathiapiprolin. CONCLUSION Glycerolipids, glycerophospholipids, and sphingolipids in P. sojae undergo significant changes with oxathiapiprolin treatment. These results provided valuable information for further understanding the function of the target protein and the mode of action of OSBPIs in oomycetes. © 2022 Society of Chemical Industry.
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Affiliation(s)
- Xiaofei Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Chengcheng Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Yue Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Ziwei Xue
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Jianqiang Miao
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
| | - Xili Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China
- Department of Plant Pathology, College of Plant Protection, China Agricultural University, Beijing, China
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22
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Che L, Huang J, Lin JX, Xu CY, Wu XM, Du ZB, Wu JS, Lin ZN, Lin YC. Aflatoxin B1 exposure triggers hepatic lipotoxicity via p53 and perilipin 2 interaction-mediated mitochondria-lipid droplet contacts: An in vitro and in vivo assessment. JOURNAL OF HAZARDOUS MATERIALS 2023; 445:130584. [PMID: 37055989 DOI: 10.1016/j.jhazmat.2022.130584] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 11/17/2022] [Accepted: 12/07/2022] [Indexed: 06/19/2023]
Abstract
Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins widely found in food contaminants, and its target organ is the liver. It poses a major food security and public health threat worldwide. However, the lipotoxicity mechanism of AFB1 exposure-induced liver injury remains unclear and requires further elucidation. Herein, we investigated the potential hepatic lipotoxicity of AFB1 exposure using in vitro and in vivo models to assess the public health hazards of high dietary AFB1 exposure. We demonstrated that low-dose of AFB1 (1.25 μM for 48 h, about one-fifth of the IC50 in HepG2 and HepaRG cells, IC50 are 5.995 μM and 5.266 μM, respectively) exposure significantly induced hepatic lipotoxicity, including abnormal lipid droplets (LDs) growth, mitochondria-LDs contacts increase, lipophagy disruption, and lipid accumulation. Mechanistically, we showed that AFB1 exposure promoted the mitochondrial p53 (mito-p53) and LDs-associated protein perilipin 2 (PLIN2) interaction-mediated mitochondria-LDs contacts, resulting in lipid accumulation in hepatocytes. Mito-p53-targeted inhibition, knockdown of PLIN2, and rapamycin application efficiently promoted the lysosome-dependent lipophagy and alleviated the hepatic lipotoxicity and liver injury induced by AFB1 exposure. Overall, our study found that mito-p53 and PLIN2 interaction mediates three organelles-mitochondria, LDs, and lysosomal networks to regulate lipid homeostasis in AFB1 exposure-induced hepatotoxicity, revealing how this unique trio of organelles works together and provides a novel insight into the targeted intervention in inter-organelle lipid sensing and trafficking for alleviating hazardous materials-induced hepatic lipotoxicity.
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Affiliation(s)
- Lin Che
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jing Huang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jin-Xian Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Chi-Yu Xu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Xin-Mou Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Ze-Bang Du
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Jia-Shen Wu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China
| | - Zhong-Ning Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
| | - Yu-Chun Lin
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen 361102, China.
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23
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Liu M, Fang X, Wang H, Ji R, Guo Q, Chen Z, Ren Q, Wang Y, Zhou Y. Characterization of lipid droplet metabolism patterns identified prognosis and tumor microenvironment infiltration in gastric cancer. Front Oncol 2023; 12:1038932. [PMID: 36713557 PMCID: PMC9875057 DOI: 10.3389/fonc.2022.1038932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023] Open
Abstract
Background Gastric cancer is one of the common malignant tumors of the digestive system worldwide, posing a serious threat to human health. A growing number of studies have demonstrated the important role that lipid droplets play in promoting cancer progression. However, few studies have systematically evaluated the role of lipid droplet metabolism-related genes (LDMRGs) in patients with gastric cancer. Methods We identified two distinct molecular subtypes in the TCGA-STAD cohort based on LDMRGs expression. We then constructed risk prediction scoring models in the TCGA-STAD cohort by lasso regression analysis and validated the model with the GSE15459 and GSE66229 cohorts. Moreover, we constructed a nomogram prediction model by cox regression analysis and evaluated the predictive efficacy of the model by various methods in STAD. Finally, we identified the key gene in LDMRGs, ABCA1, and performed a systematic multi-omics analysis in gastric cancer. Results Two molecular subtypes were identified based on LDMRGs expression with different survival prognosis and immune infiltration levels. lasso regression models were effective in predicting overall survival (OS) of gastric cancer patients at 1, 3 and 5 years and were validated in the GEO database with consistent results. The nomogram prediction model incorporated additional clinical factors and prognostic molecules to improve the prognostic predictive value of the current TNM staging system. ABCA1 was identified as a key gene in LDMRGs and multi-omics analysis showed a strong correlation between ABCA1 and the prognosis and immune status of patients with gastric cancer. Conclusion This study reveals the characteristics and possible underlying mechanisms of LDMRGs in gastric cancer, contributing to the identification of new prognostic biomarkers and providing a basis for future research.
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Affiliation(s)
- Mengxiao Liu
- The First Clinical Medical College, Lanzhou University, Lanzhou, China,Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Xidong Fang
- The First Clinical Medical College, Lanzhou University, Lanzhou, China,Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Haoying Wang
- Department of Gastroenterology, Tangdu Hospital, Fourth Military Medical University, Xinan, China
| | - Rui Ji
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Qinghong Guo
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Zhaofeng Chen
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Qian Ren
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China
| | - Yuping Wang
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China,*Correspondence: Yongning Zhou, ; Yuping Wang,
| | - Yongning Zhou
- Department of Gastroenterology, the First Hospital of Lanzhou University, Lanzhou, China,Key Laboratory for Gastrointestinal Diseases of Gansu Province, The First Hospital of Lanzhou University, Lanzhou, China,*Correspondence: Yongning Zhou, ; Yuping Wang,
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24
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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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25
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Hong Z, Adlakha J, Wan N, Guinn E, Giska F, Gupta K, Melia TJ, Reinisch KM. Mitoguardin-2-mediated lipid transfer preserves mitochondrial morphology and lipid droplet formation. J Cell Biol 2022; 221:e202207022. [PMID: 36282247 PMCID: PMC9597353 DOI: 10.1083/jcb.202207022] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 09/12/2022] [Accepted: 10/04/2022] [Indexed: 12/15/2022] Open
Abstract
Lipid transport proteins at membrane contacts, where organelles are closely apposed, are critical in redistributing lipids from the endoplasmic reticulum (ER), where they are made, to other cellular membranes. Such protein-mediated transfer is especially important for maintaining organelles disconnected from secretory pathways, like mitochondria. We identify mitoguardin-2, a mitochondrial protein at contacts with the ER and/or lipid droplets (LDs), as a lipid transporter. An x-ray structure shows that the C-terminal domain of mitoguardin-2 has a hydrophobic cavity that binds lipids. Mass spectrometry analysis reveals that both glycerophospholipids and free-fatty acids co-purify with mitoguardin-2 from cells, and that each mitoguardin-2 can accommodate up to two lipids. Mitoguardin-2 transfers glycerophospholipids between membranes in vitro, and this transport ability is required for roles both in mitochondrial and LD biology. While it is not established that protein-mediated transfer at contacts plays a role in LD metabolism, our findings raise the possibility that mitoguardin-2 functions in transporting fatty acids and glycerophospholipids at mitochondria-LD contacts.
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Affiliation(s)
- Zhouping Hong
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Jyoti Adlakha
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Neng Wan
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Emily Guinn
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Fabian Giska
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Nanobiology Institute, Yale University, West Haven, CT
| | - Kallol Gupta
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Nanobiology Institute, Yale University, West Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
| | - Thomas J. Melia
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
| | - Karin M. Reinisch
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT
- Aligning Science Across Parkinson’s Collaborative Research Network, Chevy Chase, MD
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26
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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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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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Yin H, Shan Y, Xia T, Ji Y, Yuan L, You Y, You B. Emerging Roles of Lipophagy in Cancer Metastasis. Cancers (Basel) 2022; 14:cancers14184526. [PMID: 36139685 PMCID: PMC9496701 DOI: 10.3390/cancers14184526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/13/2022] [Accepted: 09/15/2022] [Indexed: 11/16/2022] Open
Abstract
Simple Summary Metastasis is the main cause of death in patients with malignant tumors worldwide. Mounting evidence suggests lipid droplet metabolism is involved in the process of metastasis. As a mechanism to selectively degrade lipid droplets, the current research on lipophagy and tumor metastasis is quite limited. This review summarizes the crosstalk among lipophagy, tumor lipid metabolism and cancer metastasis, which will provide a new reference for the development of effective targeted drugs. Abstract Obesity is a prominent risk factor for certain types of tumor progression. Adipocytes within tumor stroma contribute to reshaping tumor microenvironment (TME) and the metabolism and metastasis of tumors through the production of cytokines and adipokines. However, the crosstalk between adipocytes and tumor cells remains a major gap in this field. Known as a subtype of selective autophagy, lipophagy is thought to contribute to lipid metabolism by breaking down intracellular lipid droplets (LDs) and generating free fatty acids (FAs). The metastatic potential of cancer cells closely correlates with the lipid degradation mechanisms, which are required for energy generation, signal transduction, and biosynthesis of membranes. Here, we discuss the recent advance in the understanding of lipophagy with tumor lipid metabolism and review current studies on the roles of lipoghagy in the metastasis of certain human malignancies. Additionally, the novel candidate drugs targeting lipophagy are integrated for effective treatment strategies.
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Affiliation(s)
- Haimeng Yin
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
| | - Ying Shan
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
- Department of Otorhinolaryngology Head and Neck surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
| | - Tian Xia
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
- Department of Otorhinolaryngology Head and Neck surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
| | - Yan Ji
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
| | - Ling Yuan
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
| | - Yiwen You
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
- Department of Otorhinolaryngology Head and Neck surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Correspondence: (Y.Y.); (B.Y.)
| | - Bo You
- Institute of Otolaryngology Head and Neck Surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Medical School, Nantong University, Qixiu Road 19, Nantong 226001, China
- Department of Otorhinolaryngology Head and Neck surgery, Affiliated Hospital of Nantong University, Xisi Road 20, Nantong 226001, China
- Correspondence: (Y.Y.); (B.Y.)
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29
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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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30
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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; 221:213393. [PMID: 35969857 PMCID: PMC9375143 DOI: 10.1083/jcb.202112107] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [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,Abdou Rachid Thiam;
| | - 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,Correspondence to Francesca Giordano:
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31
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Sánchez-Álvarez M, Del Pozo MÁ, Bosch M, Pol A. Insights Into the Biogenesis and Emerging Functions of Lipid Droplets From Unbiased Molecular Profiling Approaches. Front Cell Dev Biol 2022; 10:901321. [PMID: 35756995 PMCID: PMC9213792 DOI: 10.3389/fcell.2022.901321] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022] Open
Abstract
Lipid droplets (LDs) are spherical, single sheet phospholipid-bound organelles that store neutral lipids in all eukaryotes and some prokaryotes. Initially conceived as relatively inert depots for energy and lipid precursors, these highly dynamic structures play active roles in homeostatic functions beyond metabolism, such as proteostasis and protein turnover, innate immunity and defense. A major share of the knowledge behind this paradigm shift has been enabled by the use of systematic molecular profiling approaches, capable of revealing and describing these non-intuitive systems-level relationships. Here, we discuss these advances and some of the challenges they entail, and highlight standing questions in the field.
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Affiliation(s)
- Miguel Sánchez-Álvarez
- Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Miguel Ángel Del Pozo
- Cell and Developmental Biology Area, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain
| | - Marta Bosch
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - Albert Pol
- Lipid Trafficking and Disease Group, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.,Department of Biomedical Sciences, Faculty of Medicine, Universitat de Barcelona, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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32
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Zouiouich M, Di Mattia T, Martinet A, Eichler J, Wendling C, Tomishige N, Grandgirard E, Fuggetta N, Fromental-Ramain C, Mizzon G, Dumesnil C, Carpentier M, Reina-San-Martin B, Mathelin C, Schwab Y, Thiam AR, Kobayashi T, Drin G, Tomasetto C, Alpy F. MOSPD2 is an endoplasmic reticulum-lipid droplet tether functioning in LD homeostasis. J Cell Biol 2022; 221:213116. [PMID: 35389430 DOI: 10.1083/jcb.202110044] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 02/11/2022] [Accepted: 03/16/2022] [Indexed: 12/28/2022] Open
Abstract
Membrane contact sites between organelles are organized by protein bridges. Among the components of these contacts, the VAP family comprises ER-anchored proteins, such as MOSPD2, that function as major ER-organelle tethers. MOSPD2 distinguishes itself from the other members of the VAP family by the presence of a CRAL-TRIO domain. In this study, we show that MOSPD2 forms ER-lipid droplet (LD) contacts, thanks to its CRAL-TRIO domain. MOSPD2 ensures the attachment of the ER to LDs through a direct protein-membrane interaction. The attachment mechanism involves an amphipathic helix that has an affinity for lipid packing defects present at the surface of LDs. Remarkably, the absence of MOSPD2 markedly disturbs the assembly of lipid droplets. These data show that MOSPD2, in addition to being a general ER receptor for inter-organelle contacts, possesses an additional tethering activity and is specifically implicated in the biology of LDs via its CRAL-TRIO domain.
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Affiliation(s)
- Mehdi Zouiouich
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Thomas Di Mattia
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Arthur Martinet
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Julie Eichler
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Corinne Wendling
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Nario Tomishige
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Erwan Grandgirard
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Nicolas Fuggetta
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Catherine Fromental-Ramain
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Giulia Mizzon
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Calvin Dumesnil
- Laboratoire de Physique de l'École Normale Supérieure, Université Paris Sciences and Lettres, Centre National de la Recherche Scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Maxime Carpentier
- Laboratoire de Physique de l'École Normale Supérieure, Université Paris Sciences and Lettres, Centre National de la Recherche Scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Bernardo Reina-San-Martin
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Carole Mathelin
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France.,Institut de Cancérologie Strasbourg Europe, Strasbourg, France
| | - Yannick Schwab
- European Molecular Biology Laboratory, Cell Biology and Biophysics Unit, Heidelberg, Germany
| | - Abdou Rachid Thiam
- Laboratoire de Physique de l'École Normale Supérieure, Université Paris Sciences and Lettres, Centre National de la Recherche Scientifique, Sorbonne Université, Université de Paris, Paris, France
| | - Toshihide Kobayashi
- Laboratoire de Bioimagerie et Pathologies, UMR 7021 CNRS, Faculté de Pharmacie, Université de Strasbourg, Illkirch, France
| | - Guillaume Drin
- Université Côte d'Azur, Centre National de la Recherche Scientifique, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne, France
| | - Catherine Tomasetto
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
| | - Fabien Alpy
- IGBMC, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France.,Inserm, UMR-S 1258, Illkirch, France.,CNRS, UMR 7104, Illkirch, France.,Université de Strasbourg, IGBMC UMR 7104- UMR-S 1258, Illkirch, France
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Song L, Zhang L, Zhou Y, Shao X, Xu Y, Pei D, Wang Q. ORP5 promotes tumor metastasis via stabilizing c-Met in renal cell carcinoma. Cell Death Dis 2022; 8:219. [PMID: 35449154 PMCID: PMC9023482 DOI: 10.1038/s41420-022-01023-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/04/2022] [Accepted: 04/07/2022] [Indexed: 12/29/2022]
Abstract
ORP5, a lipid transporter, has been reported to increase the metastasis of several cancers. However, the potential mechanisms of ORP5 in renal cell carcinoma (RCC) remain unclear. In this study, we demonstrated that ORP5 was commonly overexpressed in tumor cells and tissues of RCC, and associated with tumor progression. Overexpression of ORP5 could promote RCC cells migration and invasion. In addition, the results suggested that the expression of ORP5 was favorably associated with c-Met expression, and ORP5 promoted RCC cells metastasis by upregulating c-Met in vitro and in vivo. Mechanistically, ORP5 facilitated the ubiquitination and degradation of c-Cbl (the E3 ligase of c-Met), and thus inhibited c-Met lysosomal degradation, which resulted in the stabilization of c-Met. In general, these findings revealed the role of ORP5 in contributing to tumorigenesis via upregulating c-Met in RCC.
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Affiliation(s)
- Li Song
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Lin Zhang
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Yun Zhou
- Department of Radiation Oncology, Xuzhou Central Hospital, Xuzhou, Jiangsu, 221000, China
| | - Xiaotong Shao
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Yuting Xu
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China
| | - Dongsheng Pei
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China.
| | - Qingling Wang
- Department of Pathology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, China.
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34
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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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35
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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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36
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Shi H, Wang H, Zhang C, Lu Y, Yao J, Chen Z, Xing G, Wei Q, Cao X. Mutations in OSBPL2 cause hearing loss associated with primary cilia defects via Sonic Hedgehog signaling. JCI Insight 2022; 7:149626. [PMID: 35041619 PMCID: PMC8876550 DOI: 10.1172/jci.insight.149626] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 01/12/2022] [Indexed: 11/17/2022] Open
Abstract
Defective primary cilia cause a range of diseases called ciliopathies, which include hearing loss (HL). Variants in the human oxysterol-binding protein like 2 (OSBPL2/ORP2) are responsible for autosomal dominant nonsyndromic HL (DFNA67). However, the pathogenesis of OSBPL2 deficiency has not been fully elucidated. In this study, we show that the Osbpl2-KO mice exhibited progressive HL and abnormal cochlear development with defective cilia. Further research revealed that OSBPL2 was located at the base of the kinocilia in hair cells (HCs) and primary cilia in supporting cells (SCs) and functioned in the maintenance of ciliogenesis by regulating the homeostasis of PI(4,5)P2 (phosphatidylinositol 4,5-bisphosphate) on the cilia membrane. OSBPL2 deficiency led to a significant increase of PI(4,5)P2 on the cilia membrane, which could be partially rescued by the overexpression of INPP5E. In addition, smoothened and GL13, the key molecules in the Sonic Hedgehog (Shh) signaling pathway, were detected to be downregulated in Osbpl2-KO HEI-OC1 cells. Our findings revealed that OSBPL2 deficiency resulted in ciliary defects and abnormal Shh signaling transduction in auditory cells, which helped to elucidate the underlying mechanism of OSBPL2 deficiency in HL.
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Affiliation(s)
- Hairong Shi
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Hongshun Wang
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Cheng Zhang
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Yajie Lu
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Jun Yao
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Zhibin Chen
- Department of Otolaryngology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Guangqian Xing
- Department of Otolaryngology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qinjun Wei
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
| | - Xin Cao
- Department of Medical Genetics, Nanjing Medical Univeristy, Nanjing, China
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37
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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 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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38
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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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39
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Olarte MJ, Swanson JMJ, Walther TC, Farese RV. The CYTOLD and ERTOLD pathways for lipid droplet-protein targeting. Trends Biochem Sci 2022; 47:39-51. [PMID: 34583871 PMCID: PMC8688270 DOI: 10.1016/j.tibs.2021.08.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 08/23/2021] [Accepted: 08/24/2021] [Indexed: 01/03/2023]
Abstract
Lipid droplets (LDs) are the main organelles for lipid storage, and their surfaces contain unique proteins with diverse functions, including those that facilitate the deposition and mobilization of LD lipids. Among organelles, LDs have an unusual structure with an organic, hydrophobic oil phase covered by a phospholipid monolayer. The unique properties of LD monolayer surfaces require proteins to localize to LDs by distinct mechanisms. Here we review the two pathways known to mediate direct LD protein localization: the CYTOLD pathway mediates protein targeting from the cytosol toLDs, and the ERTOLD pathway functions in protein targeting from the endoplasmic reticulum toLDs. We describe the emerging principles for each targeting pathway in animal cells and highlight open questions in the field.
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Affiliation(s)
- Maria-Jesus Olarte
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Tobias C Walther
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02124, USA.
| | - Robert V Farese
- Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA; Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of Harvard and MIT, Cambridge, MA 02124, USA.
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40
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Abstract
Exosomes are nano-sized extracellular vesicles (30–160 nm diameter) with lipid bilayer membrane secrete by various cells that mediate the communication between cells and tissue, which contain a variety of non-coding RNAs, mRNAs, proteins, lipids and other functional substances. Adipose tissue is important energy storage and endocrine organ in the organism. Recent studies have revealed that adipose tissue-derived exosomes (AT-Exosomes) play a critical role in many physiologically and pathologically functions. Physiologically, AT-Exosomes could regulate the metabolic homoeostasis of various organs or cells including liver and skeletal muscle. Pathologically, they could be used in the treatment of disease and or that they may be involved in the progression of the disease. In this review, we describe the basic principles and methods of exosomes isolation and identification, as well as further summary the specific methods. Moreover, we categorize the relevant studies of AT-Exosomes and summarize the different components and biological functions of mammalian exosomes. Most importantly, we elaborate AT-Exosomes crosstalk within adipose tissue and their functions on other tissues or organs from the physiological and pathological perspective. Based on the above analysis, we discuss what remains to be discovered problems in AT-Exosomes studies and prospect their directions needed to be further explored in the future.
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Affiliation(s)
- Rui Zhao
- Laboratory of Animal Fat Deposition & Muscle Development, College of Animal Science and Technology, Northwest A&f University, Yangling, China
| | - Tiantian Zhao
- Laboratory of Animal Fat Deposition & Muscle Development, College of Animal Science and Technology, Northwest A&f University, Yangling, China
| | - Zhaozhao He
- Laboratory of Animal Fat Deposition & Muscle Development, College of Animal Science and Technology, Northwest A&f University, Yangling, China
| | - Rui Cai
- Laboratory of Animal Fat Deposition & Muscle Development, College of Animal Science and Technology, Northwest A&f University, Yangling, China
| | - Weijun Pang
- Laboratory of Animal Fat Deposition & Muscle Development, College of Animal Science and Technology, Northwest A&f University, Yangling, China
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41
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Lalioti V, Beznoussenko GV, Mironov AA, Sandoval IV. The E-Syt3 cleavage and traffic uncovers the primordial cisterna, a new organelle that mothers the lipid droplets in the adipocyte. Traffic 2021; 23:21-41. [PMID: 34693607 DOI: 10.1111/tra.12823] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/21/2021] [Indexed: 12/27/2022]
Abstract
Extended synaptotagmins are endoplasmic reticulum proteins consisting of an SMP domain and multiple C2 domains that bind phospholipids and Ca2+ . E-Syts create contact junctions between the ER and plasma membrane (PM) to facilitate the exchange of glycerophospholipids between the apposed membranes. We find in the differentiating adipocyte that the E-Syt3 carboxyl domain is cleaved by a multi-step mechanism that includes removing the C2C domain. Confocal and live-cell time-lapse studies show that truncated E-Syt3ΔC2C, as well as endogenous E-Syt3 and the coat protein PLIN1, target the LDs from an annular, single giant ER cisterna. Inhibition of the proteasome blocks the proteolytic cleavage of Esyt3 and E-Syt3ΔC2C and causes the E-Syt3ΔC2C retention in the giant cisterna. The Esyt3 and PLIN1 distributions and LDs biogenesis show that the primordial cisterna, as we call it, is the birth and nurturing site of LDs in the adipocyte. Isoproterenol-induced lipolysis results in loss of cytoplasmic LDs and reappearance of the primordial cisterna. Electron microscopy and 3D-electron tomography studies show that the primordial cisterna consists of a tightly packed network of varicose tubules with extensively blistered membranes. Rounds of homotypic fusions from nascent to mature LDs play a central role in LD growth. The knockdown of E-Syt3 inhibits LD biogenesis. The identification of the primordial cisterna, an organelle that substitutes the randomly scattered ER foci that mother the LDs in non-adipose cells, sets the stage for a better understanding of LD biogenesis in the adipocyte.
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Affiliation(s)
- Vasiliki Lalioti
- Centro de Biología Molecular Severo Ochoa, Department of Cell Biology and Immunology, Physiological and Pathological Processes, Madrid, Spain
| | - Galina V Beznoussenko
- Laboratory of Electron Microscopy, The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Alexander A Mironov
- Laboratory of Electron Microscopy, The FIRC Institute of Molecular Oncology, Milan, Italy
| | - Ignacio V Sandoval
- Centro de Biología Molecular Severo Ochoa, Department of Cell Biology and Immunology, Physiological and Pathological Processes, Madrid, Spain
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42
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Lenoir G, D'Ambrosio JM, Dieudonné T, Čopič A. Transport Pathways That Contribute to the Cellular Distribution of Phosphatidylserine. Front Cell Dev Biol 2021; 9:737907. [PMID: 34540851 PMCID: PMC8440936 DOI: 10.3389/fcell.2021.737907] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/10/2021] [Indexed: 12/05/2022] Open
Abstract
Phosphatidylserine (PS) is a negatively charged phospholipid that displays a highly uneven distribution within cellular membranes, essential for establishment of cell polarity and other processes. In this review, we discuss how combined action of PS biosynthesis enzymes in the endoplasmic reticulum (ER), lipid transfer proteins (LTPs) acting within membrane contact sites (MCS) between the ER and other compartments, and lipid flippases and scramblases that mediate PS flip-flop between membrane leaflets controls the cellular distribution of PS. Enrichment of PS in specific compartments, in particular in the cytosolic leaflet of the plasma membrane (PM), requires input of energy, which can be supplied in the form of ATP or by phosphoinositides. Conversely, coupling between PS synthesis or degradation, PS flip-flop and PS transfer may enable PS transfer by passive flow. Such scenario is best documented by recent work on the formation of autophagosomes. The existence of lateral PS nanodomains, which is well-documented in the case of the PM and postulated for other compartments, can change the steepness or direction of PS gradients between compartments. Improvements in cellular imaging of lipids and membranes, lipidomic analysis of complex cellular samples, reconstitution of cellular lipid transport reactions and high-resolution structural data have greatly increased our understanding of cellular PS homeostasis. Our review also highlights how budding yeast has been instrumental for our understanding of the organization and transport of PS in cells.
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Affiliation(s)
- Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Juan Martín D'Ambrosio
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
| | - Thibaud Dieudonné
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alenka Čopič
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
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43
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Renne MF, Hariri H. Lipid Droplet-Organelle Contact Sites as Hubs for Fatty Acid Metabolism, Trafficking, and Metabolic Channeling. Front Cell Dev Biol 2021; 9:726261. [PMID: 34595176 PMCID: PMC8477659 DOI: 10.3389/fcell.2021.726261] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 08/12/2021] [Indexed: 01/21/2023] Open
Abstract
Cells prepare for fluctuations in nutrient availability by storing energy in the form of neutral lipids in organelles called Lipid Droplets (LDs). Upon starvation, fatty acids (FAs) released from LDs are trafficked to different cellular compartments to be utilized for membrane biogenesis or as a source of energy. Despite the biochemical pathways being known in detail, the spatio-temporal regulation of FA synthesis, storage, release, and breakdown is not completely understood. Recent studies suggest that FA trafficking and metabolism are facilitated by inter-organelle contact sites that form between LDs and other cellular compartments such as the Endoplasmic Reticulum (ER), mitochondria, peroxisomes, and lysosomes. LD-LD contact sites are also sites where FAs are transferred in a directional manner to support LD growth and expansion. As the storage site of neutral lipids, LDs play a central role in FA homeostasis. In this mini review, we highlight the role of LD contact sites with other organelles in FA trafficking, channeling, and metabolism and discuss the implications for these pathways on cellular lipid and energy homeostasis.
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Affiliation(s)
- Mike F. Renne
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
| | - Hanaa Hariri
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
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44
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Abstract
Lipid droplets (LDs) are endoplasmic reticulum-derived organelles that consist of a core of neutral lipids encircled by a phospholipid monolayer decorated with proteins. As hubs of cellular lipid and energy metabolism, LDs are inherently involved in the etiology of prevalent metabolic diseases such as obesity and nonalcoholic fatty liver disease. The functions of LDs are regulated by a unique set of associated proteins, the LD proteome, which includes integral membrane and peripheral proteins. These proteins control key activities of LDs such as triacylglycerol synthesis and breakdown, nutrient sensing and signal integration, and interactions with other organelles. Here we review the mechanisms that regulate the composition of the LD proteome, such as pathways that mediate selective and bulk LD protein degradation and potential connections between LDs and cellular protein quality control.
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Affiliation(s)
- Melissa A Roberts
- Department of Molecular and Cell Biology and Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA;
| | - James A Olzmann
- Department of Molecular and Cell Biology and Department of Nutritional Sciences and Toxicology, University of California, Berkeley, California 94720, USA; .,Chan Zuckerberg Biohub, San Francisco, California 94158, USA
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45
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Joshi AS, Ragusa JV, Prinz WA, Cohen S. Multiple C2 domain-containing transmembrane proteins promote lipid droplet biogenesis and growth at specialized endoplasmic reticulum subdomains. Mol Biol Cell 2021; 32:1147-1157. [PMID: 33826368 PMCID: PMC8351558 DOI: 10.1091/mbc.e20-09-0590] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 12/11/2022] Open
Abstract
Lipid droplets (LDs) are neutral lipid-containing organelles enclosed in a single monolayer of phospholipids. LD formation begins with the accumulation of neutral lipids within the bilayer of the endoplasmic reticulum (ER) membrane. It is not known how the sites of formation of nascent LDs in the ER membrane are determined. Here we show that multiple C2 domain-containing transmembrane proteins, MCTP1 and MCTP2, are at sites of LD formation in specialized ER subdomains. We show that the transmembrane domain (TMD) of these proteins is similar to a reticulon homology domain. Like reticulons, these proteins tubulate the ER membrane and favor highly curved regions of the ER. Our data indicate that the MCTP TMDs promote LD biogenesis, increasing LD number. MCTPs colocalize with seipin, a protein involved in LD biogenesis, but form more stable microdomains in the ER. The MCTP C2 domains bind charged lipids and regulate LD size, likely by mediating ER-LD contact sites. Together, our data indicate that MCTPs form microdomains within ER tubules that regulate LD biogenesis, size, and ER-LD contacts. Interestingly, MCTP punctae colocalized with other organelles as well, suggesting that these proteins may play a general role in linking tubular ER to organelle contact sites.
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Affiliation(s)
- Amit S. Joshi
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
- Department of Biochemistry, Cell and Molecular Biology, University of Tennessee, Knoxville, TN 37916
| | - Joey V. Ragusa
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - William A. Prinz
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20814
| | - Sarah Cohen
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
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46
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Aoyama-Ishiwatari S, Hirabayashi Y. Endoplasmic Reticulum-Mitochondria Contact Sites-Emerging Intracellular Signaling Hubs. Front Cell Dev Biol 2021; 9:653828. [PMID: 34095118 PMCID: PMC8172986 DOI: 10.3389/fcell.2021.653828] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 04/06/2021] [Indexed: 01/04/2023] Open
Abstract
It has become apparent that our textbook illustration of singular isolated organelles is obsolete. In reality, organelles form complex cooperative networks involving various types of organelles. Light microscopic and ultrastructural studies have revealed that mitochondria-endoplasmic reticulum (ER) contact sites (MERCSs) are abundant in various tissues and cell types. Indeed, MERCSs have been proposed to play critical roles in various biochemical and signaling functions such as Ca2+ homeostasis, lipid transfer, and regulation of organelle dynamics. While numerous proteins involved in these MERCS-dependent functions have been reported, how they coordinate and cooperate with each other has not yet been elucidated. In this review, we summarize the functions of mammalian proteins that localize at MERCSs and regulate their formation. We also discuss potential roles of the MERCS proteins in regulating multiple organelle contacts.
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Affiliation(s)
| | - Yusuke Hirabayashi
- Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan
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Wang T, Zhang T, Tang Y, Wang H, Wei Q, Lu Y, Yao J, Qu Y, Cao X. Oxysterol-binding protein-like 2 contributes to the developmental progression of preadipocytes by binding to β-catenin. Cell Death Discov 2021; 7:109. [PMID: 34001864 PMCID: PMC8129138 DOI: 10.1038/s41420-021-00503-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 04/28/2021] [Indexed: 02/06/2023] Open
Abstract
Oxysterol-binding protein-like 2 (OSBPL2), also known as oxysterol-binding protein-related protein (ORP) 2, is a member of lipid transfer protein well-known for its role in regulating cholesterol homeostasis. A recent study reported that OSBPL2/ORP2 localizes to lipid droplets (LDs) and is associated with energy metabolism and obesity. However, the function of OSBPL2/ORP2 in adipocyte differentiation is poorly understood. Here, we report that OSBPL2/ORP2 contributes to the developmental progression of preadipocytes. We found that OSBPL2/ORP2 binds to β-catenin, a key effector in the Wnt signaling pathway that inhibits adipogenesis. This complex plays a role in regulating the protein level of β-catenin only in preadipocytes, not in mature adipocytes. Our data further indicated that OSBPL2/ORP2 mediates the transport of β-catenin into the nucleus and thus regulates target genes related to adipocyte differentiation. Deletion of OSBPL2/ORP2 markedly reduces β-catenin both in the cytoplasm and in the nucleus, promotes preadipocytes maturation, and ultimately leads to obesity-related characteristics. Altogether, we provide novel insight into the function of OSBPL2/ORP2 in the developmental progression of preadipocytes and suggest OSBPL2/ORP2 may be a potential therapeutic target for the treatment of obesity-related diseases.
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Affiliation(s)
- Tianming Wang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Tianyu Zhang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Youzhi Tang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Hongshun Wang
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Qinjun Wei
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Yajie Lu
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Jun Yao
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China
| | - Yuan Qu
- Jiangsu Cancer Hospital, Nanjing Medical University, Nanjing, China
| | - Xin Cao
- Department of Medical Genetics, School of Basic Medical Science, Nanjing Medical University, Nanjing, China. .,Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, China.
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Casadio M. Hongyuan Yang: Tracking lipids, one droplet at a time. J Cell Biol 2021; 220:e202103075. [PMID: 33881483 PMCID: PMC8065292 DOI: 10.1083/jcb.202103075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hongyuan Yang investigates lipid trafficking and lipid droplet biogenesis.
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The C-Terminus of Perilipin 3 Shows Distinct Lipid Binding at Phospholipid-Oil-Aqueous Interfaces. MEMBRANES 2021; 11:membranes11040265. [PMID: 33917451 PMCID: PMC8067514 DOI: 10.3390/membranes11040265] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/25/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022]
Abstract
Lipid droplets (LDs) are ubiquitously expressed organelles; the only intracellular organelles that contain a lipid monolayer rather than a bilayer. Proteins localize and bind to this monolayer as they do to intracellular lipid bilayers. The mechanism by which cytosolic LD binding proteins recognize, and bind, to this lipid interface remains poorly understood. Amphipathic α-helix bundles form a common motif that is shared between cytosolic LD binding proteins (e.g., perilipins 2, 3, and 5) and apolipoproteins, such as apoE and apoLp-III, found on lipoprotein particles. Here, we use pendant drop tensiometry to expand our previous work on the C-terminal α-helix bundle of perilipin 3 and the full-length protein. We measure the recruitment and insertion of perilipin 3 at mixed lipid monolayers at an aqueous-phospholipid-oil interface. We find that, compared to its C-terminus alone, the full-length perilipin 3 has a higher affinity for both a neat oil/aqueous interface and a phosphatidylcholine (PC) coated oil/aqueous interface. Both the full-length protein and the C-terminus show significantly more insertion into a fully unsaturated PC monolayer, contrary to our previous results at the air-aqueous interface. Additionally, the C-terminus shows a preference for lipid monolayers containing phosphatidylethanolamine (PE), whereas the full-length protein does not. These results strongly support a model whereby both the N-terminal 11-mer repeat region and C-terminal amphipathic α-helix bundle domains of perilipin 3 have distinct lipid binding, and potentially biological roles.
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Interactions of Lipid Droplets with the Intracellular Transport Machinery. Int J Mol Sci 2021; 22:ijms22052776. [PMID: 33803444 PMCID: PMC7967230 DOI: 10.3390/ijms22052776] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 02/27/2021] [Accepted: 02/27/2021] [Indexed: 12/16/2022] Open
Abstract
Historically, studies of intracellular membrane trafficking have focused on the secretory and endocytic pathways and their major organelles. However, these pathways are also directly implicated in the biogenesis and function of other important intracellular organelles, the best studied of which are peroxisomes and lipid droplets. There is a large recent body of work on these organelles, which have resulted in the introduction of new paradigms regarding the roles of membrane trafficking organelles. In this review, we discuss the roles of membrane trafficking in the life cycle of lipid droplets. This includes the complementary roles of lipid phase separation and proteins in the biogenesis of lipid droplets from endoplasmic reticulum (ER) membranes, and the attachment of mature lipid droplets to membranes by lipidic bridges and by more conventional protein tethers. We also discuss the catabolism of neutral lipids, which in part results from the interaction of lipid droplets with cytosolic molecules, but with important roles for both macroautophagy and microautophagy. Finally, we address their eventual demise, which involves interactions with the autophagocytotic machinery. We pay particular attention to the roles of small GTPases, particularly Rab18, in these processes.
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