1
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Yu Q, Zou W, Liu K, Sun J, Chao Y, Sun M, Zhang Q, Wang X, Wang X, Ge L. Lipid transport protein ORP2A promotes glucose signaling by facilitating RGS1 degradation. PLANT PHYSIOLOGY 2023; 192:3170-3188. [PMID: 37073508 DOI: 10.1093/plphys/kiad238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/16/2023] [Accepted: 04/18/2023] [Indexed: 05/03/2023]
Abstract
Heterotrimeric GTP-binding proteins (G proteins) are a group of regulators essential for signal transmission into cells. Regulator of G protein signaling 1 (AtRGS1) possesses intrinsic GTPase-accelerating protein (GAP) activity and could suppress G protein and glucose signal transduction in Arabidopsis (Arabidopsis thaliana). However, how AtRGS1 activity is regulated is poorly understood. Here, we identified a knockout mutant of oxysterol binding protein-related protein 2A, orp2a-1, which exhibits similar phenotypes to the arabidopsis g-protein beta 1-2 (agb1-2) mutant. Transgenic lines overexpressing ORP2A displayed short hypocotyls, a hypersensitive response to sugar, and lower intracellular AtRGS1 levels than the control. Consistently, ORP2A interacted with AtRGS1 in vitro and in vivo. Tissue-specific expression of 2 ORP2A alternative splicing isoforms implied functions in controlling organ size and shape. Bioinformatic data and phenotypes of orp2a-1, agb1-2, and the orp2a-1 agb1-2 double mutant revealed the genetic interactions between ORP2A and Gβ in the regulation of G protein signaling and sugar response. Both alternative protein isoforms of ORP2A localized in the endoplasmic reticulum (ER), plasma membrane (PM), and ER-PM contact sites and interacted with vesicle-associated membrane protein-associated protein 27-1 (VAP27-1) in vivo and in vitro through their two phenylalanines in an acidic track-like motif. ORP2A also displayed differential phosphatidyl phosphoinositide binding activity mediated by the pleckstrin homology domain in vitro. Taken together, the Arabidopsis membrane protein ORP2A interacts with AtRGS1 and VAP27-1 to positively regulate G protein and sugar signaling by facilitating AtRGS1 degradation.
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Affiliation(s)
- Qian Yu
- The Characteristic Laboratory of Crop Germplasm Innovation and Application, Provincial Department of Education, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Wenjiao Zou
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Institute of Pharmacy, Shandong University of Traditional Chinese Medicine, Jinan 250355, China
| | - Kui Liu
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Shandong Provincial Key Laboratory of Biophysics, Dezhou University, Dezhou 253023, China
| | - Jialu Sun
- The Characteristic Laboratory of Crop Germplasm Innovation and Application, Provincial Department of Education, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Yanru Chao
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Mengyao Sun
- The Characteristic Laboratory of Crop Germplasm Innovation and Application, Provincial Department of Education, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
| | - Qianqian Zhang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
- Shandong Academy of Grape, Shandong Academy of Agricultural Sciences, Jinan 250100, China
| | - Xiaodong Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Xiaofei Wang
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
| | - Lei Ge
- The Characteristic Laboratory of Crop Germplasm Innovation and Application, Provincial Department of Education, College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China
- State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an 271018, China
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2
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Schuler B, Sladek M, Gilk SD. Host Lipid Transport Protein ORP1 Is Necessary for Coxiella burnetii Growth and Vacuole Expansion in Macrophages. mSphere 2023; 8:e0010423. [PMID: 37017523 PMCID: PMC10286706 DOI: 10.1128/msphere.00104-23] [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: 02/25/2023] [Accepted: 03/10/2023] [Indexed: 04/06/2023] Open
Abstract
Coxiella burnetii is an intracellular bacterium that causes the human disease Q fever. C. burnetii forms a large, acidic Coxiella-containing vacuole (CCV) and uses a type 4B secretion system to secrete effector proteins into the host cell cytoplasm. While the CCV membrane is rich in sterols, cholesterol accumulation in the CCV is bacteriolytic, suggesting that C. burnetii regulation of lipid transport and metabolism is critical for successful infection. The mammalian lipid transport protein ORP1L (oxysterol binding protein-like protein 1 Long) localizes to the CCV membrane and mediates CCV-endoplasmic reticulum (ER) membrane contact sites. ORP1L functions in lipid sensing and transport, including cholesterol efflux from late endosomes and lysosomes (LELs), and the ER. Its sister isoform, ORP1S (oxysterol binding protein-like protein 1 Short) also binds cholesterol but has cytoplasmic and nuclear localization. In ORP1-null cells, we found that CCVs were smaller than in wild-type cells, highlighting the importance of ORP1 in CCV development. This effect was consistent between HeLa cells and murine alveolar macrophages (MH-S cells). CCVs in ORP1-null cells had higher cholesterol content than CCVs in wild-type cells at 4 days of infection, suggesting ORP1 functions in cholesterol efflux from the CCV. While the absence of ORP1 led to a C. burnetii growth defect in MH-S cells, there was no growth defect in HeLa cells. Together, our data demonstrated that C. burnetii uses the host sterol transport protein ORP1 to promote CCV development, potentially by using ORP1 to facilitate cholesterol efflux from the CCV to diminish the bacteriolytic effects of cholesterol. IMPORTANCE Coxiella burnetii is an emerging zoonotic pathogen and bioterrorism threat. No licensed vaccine exists in the United States, and the chronic form of the disease is difficult to treat and potentially lethal. Postinfectious sequelae of C. burnetii infection, including debilitating fatigue, place a significant burden on individuals and communities recovering from an outbreak. C. burnetii must manipulate host cell processes in order to promote infection. Our results establish a link between host cell lipid transport processes and C. burnetii's avoidance of cholesterol toxicity during infection of alveolar macrophages. Elucidating the mechanisms behind bacterial manipulation of the host will yield insight for new strategies to combat this intracellular pathogen.
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Affiliation(s)
- Baleigh Schuler
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Margaret Sladek
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Stacey D. Gilk
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana, USA
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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3
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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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Rosenhouse-Dantsker A, Gazgalis D, Logothetis DE. PI(4,5)P 2 and Cholesterol: Synthesis, Regulation, and Functions. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:3-59. [PMID: 36988876 DOI: 10.1007/978-3-031-21547-6_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is the most abundant membrane phosphoinositide and cholesterol is an essential component of the plasma membrane (PM). Both lipids play key roles in a variety of cellular functions including as signaling molecules and major regulators of protein function. This chapter provides an overview of these two important lipids. Starting from a brief description of their structure, synthesis, and regulation, the chapter continues to describe the primary functions and signaling processes in which PI(4,5)P2 and cholesterol are involved. While PI(4,5)P2 and cholesterol can act independently, they often act in concert or affect each other's impact. The chapters in this volume on "Cholesterol and PI(4,5)P2 in Vital Biological Functions: From Coexistence to Crosstalk" focus on the emerging relationship between cholesterol and PI(4,5)P2 in a variety of biological systems and processes. In this chapter, the next section provides examples from the ion channel field demonstrating that PI(4,5)P2 and cholesterol can act via common mechanisms. The chapter ends with a discussion of future directions.
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Affiliation(s)
| | - Dimitris Gazgalis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
| | - Diomedes E Logothetis
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA, USA
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5
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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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6
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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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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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Zheng Koh DH, Saheki Y. Regulation of Plasma Membrane Sterol Homeostasis by Nonvesicular Lipid Transport. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211042451. [PMID: 37366378 PMCID: PMC10259818 DOI: 10.1177/25152564211042451] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Sterol contributes to the structural integrity of cellular membranes and plays an important role in the regulation of cell signaling in eukaryotes. It is either produced in the endoplasmic reticulum or taken up from the extracellular environment. In most eukaryotic cells, however, the majority of sterol is enriched in the plasma membrane. Thus, the transport of sterol between the plasma membrane and other organelles, including the endoplasmic reticulum, is crucial for maintaining sterol homeostasis. While vesicular transport that relies on membrane budding and fusion reactions plays an important role in bulk sterol transport, this mode of transport is slow and non-selective. Growing evidence suggests a critical role of nonvesicular transport mediated by evolutionarily conserved families of lipid transfer proteins in more rapid and selective delivery of sterol. Some lipid transfer proteins act primarily at the sites of contacts formed between the endoplasmic reticulum and other organelles or the plasma membrane without membrane fusion. In this review, we describe the similarities and differences of sterol biosynthesis and uptake in mammals and yeast and discuss the role of their lipid transfer proteins in maintaining plasma membrane sterol homeostasis.
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Affiliation(s)
- Dylan Hong Zheng Koh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore 308232, Singapore
- Institute of Resource Development and
Analysis, Kumamoto University, Kumamoto 860-0811, Japan
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9
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Delfosse V, Bourguet W, Drin G. Structural and Functional Specialization of OSBP-Related Proteins. ACTA ACUST UNITED AC 2020. [DOI: 10.1177/2515256420946627] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Lipids are precisely distributed in the eukaryotic cell where they help to define organelle identity and function, in addition to their structural role. Once synthesized, many lipids must be delivered to other compartments by non-vesicular routes, a process that is undertaken by proteins called Lipid Transfer Proteins (LTPs). OSBP and the closely-related ORP and Osh proteins constitute a major, evolutionarily conserved family of LTPs in eukaryotes. Most of these target one or more subcellular regions, and membrane contact sites in particular, where two organelle membranes are in close proximity. It was initially thought that such proteins were strictly dedicated to sterol sensing or transport. However, over the last decade, numerous studies have revealed that these proteins have many more functions, and we have expanded our understanding of their mechanisms. In particular, many of them are lipid exchangers that exploit PI(4)P or possibly other phosphoinositide gradients to directionally transfer sterol or PS between two compartments. Importantly, these transfer activities are tightly coupled to processes such as lipid metabolism, cellular signalling and vesicular trafficking. This review describes the molecular architecture of OSBP/ORP/Osh proteins, showing how their specific structural features and internal configurations impart unique cellular functions.
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Affiliation(s)
- Vanessa Delfosse
- Centre de Biochimie Structurale, Inserm, CNRS, Univ Montpellier, Montpellier, France
| | - William Bourguet
- Centre de Biochimie Structurale, Inserm, CNRS, Univ Montpellier, Montpellier, France
| | - Guillaume Drin
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d’Azur, Valbonne, France
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10
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Upregulation of OSBPL3 by HIF1A promotes colorectal cancer progression through activation of RAS signaling pathway. Cell Death Dis 2020; 11:571. [PMID: 32709922 PMCID: PMC7381633 DOI: 10.1038/s41419-020-02793-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 07/07/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022]
Abstract
Oxysterol-binding protein like protein 3 (OSBPL3) has been shown involving in the development of several human cancers. However, the relationship between OSBPL3 and colorectal cancer (CRC), particularly the role of OSBPL3 in the proliferation, invasion and metastasis of CRC remains unclear. In this study, we investigated the role of OSBPL3 in CRC and found that its expression was significantly higher in CRC tissues than that in normal tissues. In addition, high expression of OSBPL3 was closely related to poor differentiation, advanced TNM stage and poor prognosis of CRC. Further experiments showed that over-expression of OSBPL3 promoted the proliferation, invasion and metastasis of CRC in vitro and in vivo models. Moreover, we revealed that OSBPL3 promoted CRC progression through activation of RAS signaling pathway. Furthermore, we demonstrated that hypoxia induced factor 1 (HIF-1A) can regulate the expression of OSBPL3 via binding to the hypoxia response element (HRE) in the promoter of OSBPL3. In summary, Upregulation of OSBPL3 by HIF1A promotes colorectal cancer progression through activation of RAS signaling pathway. This novel mechanism provides a comprehensive understanding of both OSBPL3 and the RAS signaling pathway in the progression of CRC and indicates that the HIF1A–OSBPL3–RAS axis is a potential target for early therapeutic intervention in CRC progression.
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11
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Lipp NF, Ikhlef S, Milanini J, Drin G. Lipid Exchangers: Cellular Functions and Mechanistic Links With Phosphoinositide Metabolism. Front Cell Dev Biol 2020; 8:663. [PMID: 32793602 PMCID: PMC7385082 DOI: 10.3389/fcell.2020.00663] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 07/01/2020] [Indexed: 12/28/2022] Open
Abstract
Lipids are amphiphilic molecules that self-assemble to form biological membranes. Thousands of lipid species coexist in the cell and, once combined, define organelle identity. Due to recent progress in lipidomic analysis, we now know how lipid composition is finely tuned in different subcellular regions. Along with lipid synthesis, remodeling and flip-flop, lipid transfer is one of the active processes that regulates this intracellular lipid distribution. It is mediated by Lipid Transfer Proteins (LTPs) that precisely move certain lipid species across the cytosol and between the organelles. A particular subset of LTPs from three families (Sec14, PITP, OSBP/ORP/Osh) act as lipid exchangers. A striking feature of these exchangers is that they use phosphatidylinositol or phosphoinositides (PIPs) as a lipid ligand and thereby have specific links with PIP metabolism and are thus able to both control the lipid composition of cellular membranes and their signaling capacity. As a result, they play pivotal roles in cellular processes such as vesicular trafficking and signal transduction at the plasma membrane. Recent data have shown that some PIPs are used as energy by lipid exchangers to generate lipid gradients between organelles. Here we describe the importance of lipid counter-exchange in the cell, its structural basis, and presumed links with pathologies.
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Affiliation(s)
- Nicolas-Frédéric Lipp
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Souade Ikhlef
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Julie Milanini
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
| | - Guillaume Drin
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, Université Côte d'Azur, Valbonne, France
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12
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Zhao K, Foster J, Ridgway ND. Oxysterol-binding protein-related protein 1 variants have opposing cholesterol transport activities from the endolysosomes. Mol Biol Cell 2020; 31:793-802. [PMID: 32023146 PMCID: PMC7185962 DOI: 10.1091/mbc.e19-12-0697] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
OSBPL1 encodes the full-length oxysterol-binding protein-related protein ORP1L, which transports LDL-derived cholesterol at membrane contacts between the late endosomes/lysosomes (LEL) and the endoplasmic reticulum (ER). OSBPL1 also encodes the truncated variant ORP1S that contains only the C-terminal lipid binding domain. HeLa cells in which both variants were knocked out (ORP1-null) were used to determine the functional relationship between ORP1L and ORP1S with respect to cellular cholesterol localization and regulation. ORP1-null cells accumulated cholesterol in LEL and had reduced plasma membrane (PM) cholesterol. PM cholesterol was restored by expression of wild-type ORP1S or a phosphatidylinositol phosphate-binding mutant but not by a sterol-binding mutant. Expression of ORP2, another truncated variant, also restored PM cholesterol in ORP1-null cells. Consistent with a LEL-to-PM cholesterol transport activity, a small fraction of ORP1S was detected on the PM. As a consequence of reduced delivery of cholesterol to the PM in ORP1-null cells, cholesterol was diverted to the ER resulting in normalization of de novo cholesterol synthesis. The deficiency in PM cholesterol also reduced ABCA1-dependent cholesterol efflux and LDL receptor activity in ORP1-null cells. We conclude that ORP1S, which lacks discrete membrane-targeting motifs, transports cholesterol from LEL to the PM.
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Affiliation(s)
- Kexin Zhao
- Departments of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jason Foster
- Departments of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Neale D Ridgway
- Departments of Pediatrics and Biochemistry & Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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Hansmann E, Mennillo E, Yoda E, Verreault M, Barbier O, Chen S, Tukey RH. Differential Role of Liver X Receptor (LXR) α and LXR β in the Regulation of UDP-Glucuronosyltransferase 1A1 in Humanized UGT1 Mice. Drug Metab Dispos 2020; 48:255-263. [PMID: 31980500 DOI: 10.1124/dmd.119.090068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/14/2020] [Indexed: 12/17/2022] Open
Abstract
Liver X receptors (LXRs), LXRα and LXRβ, are nuclear receptors that regulate the metabolism of cholesterol and bile acids and are activated by oxysterols. Humanized UGT1 (hUGT1) mice express the 9-human UGT1A genes associated with the UGT1 locus in a Ugt1-null background. The expression of UGT1A1 is developmentally delayed in the liver and intestines, resulting in the accumulation of serum bilirubin during the neonatal period. Induction of UGT1A1 in newborn hUGT1 mice leads to rapid reduction in total serum bilirubin (TSB) levels, a phenotype measurement that allows for an accurate prediction on UGT1A1 expression. When neonatal hUGT1 mice were treated by oral gavage with the LXR agonist T0901317, TSB levels were dramatically reduced. To determine the LXR contribution to the induction of UGT1A1 and the lowering of TSB levels, experiments were conducted in neonatal hUGT1/Lxrα -/- , hUGT1/Lxrβ -/- , and hUGT1/Lxrαβ -/- mice treated with T0901317. Induction of liver UGT1A1 was dependent upon LXRα, with the induction pattern paralleling induction of LXRα-specific stearoyl CoA desaturase 1. However, the actions of T0901317 were also shown to display a lack of specificity for LXR, with the induction of liver UGT1A1 in hUGT1/Lxrαβ -/- mice, a result associated with activation of both pregnane X receptor and constitutive androstane receptor. However, the LXR agonist GW3965 was highly selective toward LXRα, showing no impact on lowering TSB values or inducing UGT1A1 in hUGT1/Lxrα -/- mice. An LXR-specific enhancer site on the UGT1A1 gene was identified, along with convincing evidence that LXRα is crucial in maintaining constitutive expression of UGT1A1 in adult hUGT1 mice. SIGNIFICANCE STATEMENT: It has been established that activation of LXRα, and not LXRβ, is responsible for the induction of liver UGT1A1 and metabolism of serum bilirubin in neonatal hUGT1 mice. Although induction of the human UGT1A1 gene is initiated at a newly characterized LXR enhancer site, allelic deletion of the Lxrα gene drastically reduces the constitutive expression of liver UGT1A1 in adult hUGT1 mice. Combined, these findings indicate that LXRα is critical for the developmental expression of UGT1A1.
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Affiliation(s)
- Eva Hansmann
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Elvira Mennillo
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Emiko Yoda
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Mélanie Verreault
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Olivier Barbier
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Shujuan Chen
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Robert H Tukey
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
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14
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Fowler PC, Garcia-Pardo ME, Simpson JC, O'Sullivan NC. NeurodegenERation: The Central Role for ER Contacts in Neuronal Function and Axonopathy, Lessons From Hereditary Spastic Paraplegias and Related Diseases. Front Neurosci 2019; 13:1051. [PMID: 31680803 PMCID: PMC6801308 DOI: 10.3389/fnins.2019.01051] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/19/2019] [Indexed: 12/17/2022] Open
Abstract
The hereditary spastic paraplegias (HSPs) are a group of inherited neurodegenerative conditions whose characteristic feature is degeneration of the longest axons within the corticospinal tract which leads to progressive spasticity and weakness of the lower limbs. Though highly genetically heterogeneous, the majority of HSP cases are caused by mutations in genes encoding proteins that are responsible for generating and organizing the tubular endoplasmic reticulum (ER). Despite this, the role of the ER within neurons, particularly the long axons affected in HSP, is not well understood. Throughout axons, ER tubules make extensive contacts with other organelles, the cytoskeleton and the plasma membrane. At these ER contacts, protein complexes work in concert to perform specialized functions including organelle shaping, calcium homeostasis and lipid biogenesis, all of which are vital for neuronal survival and may be disrupted by HSP-causing mutations. In this article we summarize the proteins which mediate ER contacts, review the functions these contacts are known to carry out within neurons, and discuss the potential contribution of disruption of ER contacts to axonopathy in HSP.
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Affiliation(s)
- Philippa C Fowler
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - M Elena Garcia-Pardo
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Jeremy C Simpson
- UCD School of Biology and Environmental Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
| | - Niamh C O'Sullivan
- UCD School of Biomolecular and Biomedical Science, UCD Conway Institute, University College Dublin, Dublin, Ireland
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15
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Levin-Konigsberg R, Montaño-Rendón F, Keren-Kaplan T, Li R, Ego B, Mylvaganam S, DiCiccio JE, Trimble WS, Bassik MC, Bonifacino JS, Fairn GD, Grinstein S. Phagolysosome resolution requires contacts with the endoplasmic reticulum and phosphatidylinositol-4-phosphate signalling. Nat Cell Biol 2019; 21:1234-1247. [PMID: 31570833 DOI: 10.1038/s41556-019-0394-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 08/19/2019] [Indexed: 01/01/2023]
Abstract
Phosphoinositides have a pivotal role in the maturation of nascent phagosomes into microbicidal phagolysosomes. Following degradation of their contents, mature phagolysosomes undergo resolution, a process that remains largely uninvestigated. Here we studied the role of phosphoinositides in phagolysosome resolution. Phosphatidylinositol-4-phosphate (PtdIns(4)P), which is abundant in maturing phagolysosomes, was depleted as they tubulated and resorbed. Depletion was caused, in part, by transfer of phagolysosomal PtdIns(4)P to the endoplasmic reticulum, a process mediated by oxysterol-binding protein-related protein 1L (ORP1L), a RAB7 effector. ORP1L formed discrete tethers between the phagolysosome and the endoplasmic reticulum, resulting in distinct regions with alternating PtdIns(4)P depletion and enrichment. Tubules emerged from PtdIns(4)P-rich regions, where ADP-ribosylation factor-like protein 8B (ARL8B) and SifA- and kinesin-interacting protein/pleckstrin homology domain-containing family M member 2 (SKIP/PLEKHM2) accumulated. SKIP binds preferentially to monophosphorylated phosphoinositides, of which PtdIns(4)P is most abundant in phagolysosomes, contributing to their tubulation. Accordingly, premature hydrolysis of PtdIns(4)P impaired SKIP recruitment and phagosome resolution. Thus, resolution involves phosphoinositides and tethering of phagolysosomes to the endoplasmic reticulum.
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Affiliation(s)
- Roni Levin-Konigsberg
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.,Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Fernando Montaño-Rendón
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Tal Keren-Kaplan
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Ren Li
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Braeden Ego
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Sivakami Mylvaganam
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jessica E DiCiccio
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - William S Trimble
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Michael C Bassik
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, USA
| | - Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada. .,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
| | - Sergio Grinstein
- Division of Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada. .,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada. .,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada. .,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada.
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16
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Di Mattia T, Tomasetto C, Alpy F. Faraway, so close! Functions of Endoplasmic reticulum-Endosome contacts. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158490. [PMID: 31252175 DOI: 10.1016/j.bbalip.2019.06.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 06/18/2019] [Accepted: 06/20/2019] [Indexed: 01/27/2023]
Abstract
Eukaryotic cells are partitioned into functionally distinct organelles. Long considered as independent units in the cytosol, organelles are actually in constant and direct interaction with each other, mostly through the establishment of physical connections named membrane contact sites. Membrane contact sites constitute specific active regions involved in organelle dynamics, inter-organelle exchanges and communications. The endoplasmic reticulum (ER), which spreads throughout the cytosol, forms an extensive network that has many connections with the other organelles of the cell. Ample connections between the ER and endocytic organelles are observed in many cell types, highlighting their prominent physiological roles. Even though morphologically similar - a contact is a contact -, the identity of ER-Endosome contacts is defined by their specific molecular composition, which in turn determines the function of the contact. Here, we review the molecular mechanisms of ER-Endosome contact site formation and their associated cellular functions. This article is part of a Special Issue entitled Endoplasmic reticulum platforms for lipid dynamics edited by Shamshad Cockcroft and Christopher Stefan.
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Affiliation(s)
- Thomas Di Mattia
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Catherine Tomasetto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France; Université de Strasbourg, Illkirch, France.
| | - Fabien Alpy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France; Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France; Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France; Université de Strasbourg, Illkirch, France.
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17
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Jamecna D, Polidori J, Mesmin B, Dezi M, Levy D, Bigay J, Antonny B. An Intrinsically Disordered Region in OSBP Acts as an Entropic Barrier to Control Protein Dynamics and Orientation at Membrane Contact Sites. Dev Cell 2019; 49:220-234.e8. [DOI: 10.1016/j.devcel.2019.02.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 12/19/2018] [Accepted: 02/16/2019] [Indexed: 01/08/2023]
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18
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Luo J, Jiang LY, Yang H, Song BL. Intracellular Cholesterol Transport by Sterol Transfer Proteins at Membrane Contact Sites. Trends Biochem Sci 2019; 44:273-292. [DOI: 10.1016/j.tibs.2018.10.001] [Citation(s) in RCA: 70] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/06/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022]
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19
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Qiu S, Zeng B. Advances in understanding of the oxysterol-binding protein homologous in yeast and filamentous fungi. Int Microbiol 2019; 22:169-179. [PMID: 30810998 DOI: 10.1007/s10123-019-00056-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/02/2019] [Accepted: 01/03/2019] [Indexed: 01/14/2023]
Abstract
Oxysterol-binding protein is an important non-vesicular trafficking protein involved in the transportation of lipids in eukaryotic cells. Oxysterol-binding protein is identified as oxysterol-binding protein-related proteins (ORPs) in mammals and oxysterol-binding protein homologue (Osh) in yeast. Research has described the function and structure of oxysterol-binding protein in mammals and yeast, but little information about the protein's structure and function in filamentous fungi has been reported. This article focuses on recent advances in the research of Osh proteins in yeast and filamentous fungi, such as Aspergillus oryzae, Aspergillus nidulans, and Candida albicans. Furthermore, we point out some problems in the field, summarizing the membrane contact sites (MCS) of Osh proteins in yeast, and consider the future of Osh protein development.
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Affiliation(s)
- Shangkun Qiu
- Jiangxi Province Key Laboratory Bioprocess Engineering, Jiangxi Science and Technology Normal University, Nanchang, 330013, China
| | - Bin Zeng
- Jiangxi Province Key Laboratory Bioprocess Engineering, Jiangxi Science and Technology Normal University, Nanchang, 330013, China.
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20
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Tong J, Tan L, Chun C, Im YJ. Structural basis of human ORP1-Rab7 interaction for the late-endosome and lysosome targeting. PLoS One 2019; 14:e0211724. [PMID: 30721249 PMCID: PMC6363164 DOI: 10.1371/journal.pone.0211724] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 01/20/2019] [Indexed: 02/07/2023] Open
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute a family of lipid transfer proteins conserved in eukaryotes. ORP1 transports cholesterol at the interface between the late endosomes/lysosomes (LELs) and the endoplasmic reticulum (ER). ORP1 is targeted to the endosomal membranes by forming a tripartite complex with the LE GTPase Rab7 and its effector RILP (Rab7-interacting lysosomal protein). Here, we determined the crystal structure of human ORP1 ANK domain in complex with the GTP-bound form of Rab7. ORP1 ANK binds to the helix α3 of Rab7 located away from the switching regions, which makes the interaction independent of the nucleotide-binding state of Rab7. Thus, the effector-interacting switch regions of Rab7 are accessible for RILP binding, allowing formation of the ORP1-Rab7-RILP complex. ORP1 ANK binds to Rab7 and the Rab7-RILP complex with similar micro-molar affinities, which is consistent with the independence binding of ORP1 and RILP to Rab7. The structural model of the ORP1-Rab7-RILP complex correlates with the recruitment of ORP1 at the LEL-ER interface and the role in lipid transport and regulation.
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Affiliation(s)
- Junsen Tong
- College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
| | - Lingchen Tan
- College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
| | - ChangJu Chun
- College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
| | - Young Jun Im
- College of Pharmacy, Chonnam National University, Gwangju, Republic of Korea
- * E-mail:
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21
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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22
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Pietrangelo A, Ridgway ND. Bridging the molecular and biological functions of the oxysterol-binding protein family. Cell Mol Life Sci 2018; 75:3079-3098. [PMID: 29536114 PMCID: PMC11105248 DOI: 10.1007/s00018-018-2795-y] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/18/2018] [Accepted: 03/07/2018] [Indexed: 12/19/2022]
Abstract
Oxysterol-binding protein (OSBP) and OSBP-related proteins (ORPs) constitute a large eukaryotic gene family that transports and regulates the metabolism of sterols and phospholipids. The original classification of the family based on oxysterol-binding activity belies the complex dual lipid-binding specificity of the conserved OSBP homology domain (OHD). Additional protein- and membrane-interacting modules mediate the targeting of select OSBP/ORPs to membrane contact sites between organelles, thus positioning the OHD between opposing membranes for lipid transfer and metabolic regulation. This unique subcellular location, coupled with diverse ligand preferences and tissue distribution, has identified OSBP/ORPs as key arbiters of membrane composition and function. Here, we will review how molecular models of OSBP/ORP-mediated intracellular lipid transport and regulation at membrane contact sites relate to their emerging roles in cellular and organismal functions.
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Affiliation(s)
- Antonietta Pietrangelo
- Atlantic Research Center, C306 CRC Bldg, Department of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, 5849 University Av., Halifax, NS, B3H4R2, Canada
| | - Neale D Ridgway
- Atlantic Research Center, C306 CRC Bldg, Department of Pediatrics, and Biochemistry and Molecular Biology, Dalhousie University, 5849 University Av., Halifax, NS, B3H4R2, Canada.
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23
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Hanada K. Lipid transfer proteins rectify inter-organelle flux and accurately deliver lipids at membrane contact sites. J Lipid Res 2018; 59:1341-1366. [PMID: 29884707 PMCID: PMC6071762 DOI: 10.1194/jlr.r085324] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 05/24/2018] [Indexed: 12/22/2022] Open
Abstract
The endoplasmic reticulum (ER) is the main center for the synthesis of various lipid types in cells, and newly synthesized lipids are delivered from the ER to other organelles. In the past decade, various lipid transfer proteins (LTPs) have been recognized as mediators of lipid transport from the ER to other organelles; inter-organelle transport occurs at membrane contact sites (MCSs) and in a nonvesicular manner. Although the intermembrane transfer reaction catalyzed by LTPs is an equilibrium reaction, various types of newly synthesized lipids are transported unidirectionally in cells. This review provides a brief history of the inter-organelle trafficking of lipids and summarizes the structural and biochemical characteristics of the ceramide transport protein (CERT) as a typical LTP acting at MCSs. In addition, this review compares several LTP-mediated inter-organelle lipid trafficking systems and proposes that LTPs generate unidirectional fluxes of specific lipids between different organelles by indirect coupling with the metabolic reactions that occur in specific organelles. Moreover, the available data also suggest that the major advantage of LTP-mediated lipid transport at MCSs may be the accuracy of delivery. Finally, how cholesterol is enriched in the plasma membrane is discussed from a thermodynamic perspective.
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Affiliation(s)
- Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, Shinjuku-ku, Tokyo 162-8640, Japan
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24
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Di Mattia T, Wilhelm LP, Ikhlef S, Wendling C, Spehner D, Nominé Y, Giordano F, Mathelin C, Drin G, Tomasetto C, Alpy F. Identification of MOSPD2, a novel scaffold for endoplasmic reticulum membrane contact sites. EMBO Rep 2018; 19:e45453. [PMID: 29858488 PMCID: PMC6030701 DOI: 10.15252/embr.201745453] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 11/09/2022] Open
Abstract
Membrane contact sites are cellular structures that mediate interorganelle exchange and communication. The two major tether proteins of the endoplasmic reticulum (ER), VAP-A and VAP-B, interact with proteins from other organelles that possess a small VAP-interacting motif, named FFAT [two phenylalanines (FF) in an acidic track (AT)]. In this study, using an unbiased proteomic approach, we identify a novel ER tether named motile sperm domain-containing protein 2 (MOSPD2). We show that MOSPD2 possesses a Major Sperm Protein (MSP) domain which binds FFAT motifs and consequently allows membrane tethering in vitro MOSPD2 is an ER-anchored protein, and it interacts with several FFAT-containing tether proteins from endosomes, mitochondria, or Golgi. Consequently, MOSPD2 and these organelle-bound proteins mediate the formation of contact sites between the ER and endosomes, mitochondria, or Golgi. Thus, we characterized here MOSPD2, a novel tethering component related to VAP proteins, bridging the ER with a variety of distinct organelles.
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Affiliation(s)
- Thomas Di Mattia
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Léa P Wilhelm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Souade Ikhlef
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Corinne Wendling
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Danièle Spehner
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Yves Nominé
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Francesca Giordano
- Institut de Biologie Intégrative de la Cellule, CEA, CNRS, Paris-Sud University Paris-Saclay University, Gif-sur-Yvette Cedex 91198, France
| | - Carole Mathelin
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Senology Unit, Strasbourg University Hospital (CHRU), Hôpital de Hautepierre, Strasbourg, France
| | - Guillaume Drin
- CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, Université Côte d'Azur, Valbonne, France
| | - Catherine Tomasetto
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Fabien Alpy
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
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25
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Zhao K, Ridgway ND. Oxysterol-Binding Protein-Related Protein 1L Regulates Cholesterol Egress from the Endo-Lysosomal System. Cell Rep 2018; 19:1807-1818. [PMID: 28564600 DOI: 10.1016/j.celrep.2017.05.028] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/13/2017] [Accepted: 05/08/2017] [Indexed: 02/02/2023] Open
Abstract
Lipoprotein cholesterol is delivered to the limiting membrane of late endosomes/lysosomes (LELs) by Niemann-Pick C1 (NPC1). However, the mechanism of cholesterol transport from LELs to the endoplasmic reticulum (ER) is poorly characterized. We report that oxysterol-binding protein-related protein 1L (ORP1L) is necessary for this stage of cholesterol export. CRISPR-mediated knockout of ORP1L in HeLa and HEK293 cells reduced esterification of cholesterol to the level in NPC1 knockout cells, and it increased the expression of sterol-regulated genes and de novo cholesterol synthesis, indicative of a block in cholesterol transport to the ER. In the absence of this transport pathway, cholesterol-enriched LELs accumulated in the Golgi/perinuclear region. Cholesterol delivery to the ER required the sterol-, phosphatidylinositol 4-phosphate-, and vesicle-associated membrane protein-associated protein (VAP)-binding activities of ORP1L, as well as NPC1 expression. These results suggest that ORP1L-dependent membrane contacts between LELs and the ER coordinate cholesterol transfer with the retrograde movement of endo-lysosomal vesicles.
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Affiliation(s)
- Kexin Zhao
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Box 15000, Halifax, NS B3H 4R2, Canada
| | - Neale D Ridgway
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, Dalhousie University, Box 15000, Halifax, NS B3H 4R2, Canada.
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26
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A Lipid Transfer Protein Signaling Axis Exerts Dual Control of Cell-Cycle and Membrane Trafficking Systems. Dev Cell 2018; 44:378-391.e5. [PMID: 29396115 DOI: 10.1016/j.devcel.2017.12.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 09/24/2017] [Accepted: 12/28/2017] [Indexed: 11/21/2022]
Abstract
Kes1/Osh4 is a member of the conserved, but functionally enigmatic, oxysterol binding protein-related protein (ORP) superfamily that inhibits phosphatidylinositol transfer protein (Sec14)-dependent membrane trafficking through the trans-Golgi (TGN)/endosomal network. We now report that Kes1, and select other ORPs, execute cell-cycle control activities as functionally non-redundant inhibitors of the G1/S transition when cells confront nutrient-poor environments and promote replicative aging. Kes1-dependent cell-cycle regulation requires the Greatwall/MASTL kinase ortholog Rim15, and is opposed by Sec14 activity in a mechanism independent of Kes1/Sec14 bulk membrane-trafficking functions. Moreover, the data identify Kes1 as a non-histone target for NuA4 through which this lysine acetyltransferase co-modulates membrane-trafficking and cell-cycle activities. We propose the Sec14/Kes1 lipid-exchange protein pair constitutes part of the mechanism for integrating TGN/endosomal lipid signaling with cell-cycle progression and hypothesize that ORPs define a family of stage-specific cell-cycle control factors that execute tumor-suppressor-like functions.
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27
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Inter-Species Host Gene Expression Differences in Response to Human and Avian Influenza A Virus Strains. Int J Mol Sci 2017; 18:ijms18112295. [PMID: 29104227 PMCID: PMC5713265 DOI: 10.3390/ijms18112295] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/25/2017] [Accepted: 10/25/2017] [Indexed: 01/08/2023] Open
Abstract
Low pathogenic avian influenza (LPAI) viruses are a source of sporadic human infections and could also contribute to future pandemic outbreaks but little is known about inter-species differences in the host responses to these viruses. Here, we studied host gene expression signatures of cell lines from three species (human, chicken, and canine) in response to six different viruses (H1N1/WSN, H5N2/F59, H5N2/F118, H5N2/F189, H5N3 and H9N2). Comprehensive microarray probe set re-annotation and ortholog mapping of the host genes was necessary to allow comparison over extended functionally annotated gene sets and orthologous pathways. The annotations are made available to the community for commonly used microarray chips. We observe a strong tendency of the response being cell type- rather than virus-specific. In chicken cells, we found up-regulation of host factors inducing virus infectivity (e.g., oxysterol binding protein like 1A (OSBPL1A) and Rho GTPase activating protein 21 (ARHGAP21)) while reducing apoptosis (e.g., mitochondrial ribosomal protein S27 (MRPS27)) and increasing cell proliferation (e.g., COP9 signalosome subunit 2 (COPS2)). On the other hand, increased antiviral, pro-apoptotic and inflammatory signatures have been identified in human cells while cell cycle and metabolic pathways were down-regulated. This signature describes how low pathogenic avian influenza (LPAI) viruses are being tolerated and shed from chicken but potentially causing cellular disruption in mammalian cells.
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28
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Manik MK, Yang H, Tong J, Im YJ. Structure of Yeast OSBP-Related Protein Osh1 Reveals Key Determinants for Lipid Transport and Protein Targeting at the Nucleus-Vacuole Junction. Structure 2017; 25:617-629.e3. [PMID: 28319008 DOI: 10.1016/j.str.2017.02.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/19/2017] [Accepted: 02/22/2017] [Indexed: 01/25/2023]
Abstract
Yeast Osh1 belongs to the oxysterol-binding protein (OSBP) family of proteins and contains multiple targeting modules optimized for lipid transport at the nucleus-vacuole junction (NVJ). The key determinants for NVJ targeting and the role of Osh1 at NVJs have remained elusive because of unknown lipid specificities. In this study, we determined the structures of the ankyrin repeat domain (ANK), and OSBP-related domain (ORD) of Osh1, in complex with Nvj1 and ergosterol, respectively. The Osh1 ANK forms a unique bi-lobed structure that recognizes a cytosolic helical segment of Nvj1. We discovered that Osh1 ORD binds ergosterol and phosphatidylinositol 4-phosphate PI(4)P in a competitive manner, suggesting counter-transport function of the two lipids. Ergosterol is bound to the hydrophobic pocket in a head-down orientation, and the structure of the PI(4)P-binding site in Osh1 is well conserved. Our results suggest that Osh1 performs non-vesicular transport of ergosterol and PI(4)P at the NVJ.
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Affiliation(s)
| | - Huiseon Yang
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Junsen Tong
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Young Jun Im
- College of Pharmacy, Chonnam National University, Gwangju 61186, Republic of Korea.
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29
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Intracellular cholesterol transport proteins: roles in health and disease. Clin Sci (Lond) 2016; 130:1843-59. [DOI: 10.1042/cs20160339] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/12/2016] [Indexed: 12/13/2022]
Abstract
Effective cholesterol homoeostasis is essential in maintaining cellular function, and this is achieved by a network of lipid-responsive nuclear transcription factors, and enzymes, receptors and transporters subject to post-transcriptional and post-translational regulation, whereas loss of these elegant, tightly regulated homoeostatic responses is integral to disease pathologies. Recent data suggest that sterol-binding sensors, exchangers and transporters contribute to regulation of cellular cholesterol homoeostasis and that genetic overexpression or deletion, or mutations, in a number of these proteins are linked with diseases, including atherosclerosis, dyslipidaemia, diabetes, congenital lipoid adrenal hyperplasia, cancer, autosomal dominant hearing loss and male infertility. This review focuses on current evidence exploring the function of members of the ‘START’ (steroidogenic acute regulatory protein-related lipid transfer) and ‘ORP’ (oxysterol-binding protein-related proteins) families of sterol-binding proteins in sterol homoeostasis in eukaryotic cells, and the evidence that they represent valid therapeutic targets to alleviate human disease.
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30
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Tong J, Manik MK, Yang H, Im YJ. Structural insights into nonvesicular lipid transport by the oxysterol binding protein homologue family. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:928-939. [DOI: 10.1016/j.bbalip.2016.01.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 12/23/2015] [Accepted: 01/14/2016] [Indexed: 10/22/2022]
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31
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Justis AV, Hansen B, Beare PA, King KB, Heinzen RA, Gilk SD. Interactions between the Coxiella burnetii parasitophorous vacuole and the endoplasmic reticulum involve the host protein ORP1L. Cell Microbiol 2016; 19. [PMID: 27345457 DOI: 10.1111/cmi.12637] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 06/06/2016] [Accepted: 06/17/2016] [Indexed: 01/07/2023]
Abstract
Coxiella burnetii is a gram-negative intracellular bacterium that forms a large, lysosome-like parasitophorous vacuole (PV) essential for bacterial replication. Host membrane lipids are critical for the formation and maintenance of this intracellular niche, yet the mechanisms by which Coxiella manipulates host cell lipid metabolism, trafficking and signalling are unknown. Oxysterol-binding protein-related protein 1 long (ORP1L) is a mammalian lipid-binding protein that plays a dual role in cholesterol-dependent endocytic trafficking as well as interactions between endosomes and the endoplasmic reticulum (ER). We found that ORP1L localized to the Coxiella PV within 12 h of infection through a process requiring the Coxiella Dot/Icm Type 4B secretion system, which secretes effector proteins into the host cell cytoplasm where they manipulate trafficking and signalling pathways. The ORP1L N-terminal ankyrin repeats were necessary and sufficient for PV localization, indicating that ORP1L binds a PV membrane protein. Strikingly, ORP1L simultaneously co-localized with the PV and ER, and electron microscopy revealed membrane contact sites between the PV and ER membranes. In ORP1L-depleted cells, PVs were significantly smaller than PVs from control cells. These data suggest that ORP1L is specifically recruited by the bacteria to the Coxiella PV, where it influences PV membrane dynamics and interactions with the ER.
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Affiliation(s)
- Anna V Justis
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Bryan Hansen
- Research Technology Branch, National Institutes of Health, Hamilton, MT, USA
| | - Paul A Beare
- Laboratory of Bacteriology, Rocky Mountain Labs, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Kourtney B King
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert A Heinzen
- Laboratory of Bacteriology, Rocky Mountain Labs, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT, USA
| | - Stacey D Gilk
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
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32
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A loss-of-function variant in OSBPL1A predisposes to low plasma HDL cholesterol levels and impaired cholesterol efflux capacity. Atherosclerosis 2016; 249:140-7. [DOI: 10.1016/j.atherosclerosis.2016.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 04/02/2016] [Accepted: 04/05/2016] [Indexed: 12/25/2022]
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33
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Martínez-Redondo V, Jannig PR, Correia JC, Ferreira DMS, Cervenka I, Lindvall JM, Sinha I, Izadi M, Pettersson-Klein AT, Agudelo LZ, Gimenez-Cassina A, Brum PC, Dahlman-Wright K, Ruas JL. Peroxisome Proliferator-activated Receptor γ Coactivator-1 α Isoforms Selectively Regulate Multiple Splicing Events on Target Genes. J Biol Chem 2016; 291:15169-84. [PMID: 27231350 DOI: 10.1074/jbc.m115.705822] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Indexed: 11/06/2022] Open
Abstract
Endurance and resistance exercise training induces specific and profound changes in the skeletal muscle transcriptome. Peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α) coactivators are not only among the genes differentially induced by distinct training methods, but they also participate in the ensuing signaling cascades that allow skeletal muscle to adapt to each type of exercise. Although endurance training preferentially induces PGC-1α1 expression, resistance exercise activates the expression of PGC-1α2, -α3, and -α4. These three alternative PGC-1α isoforms lack the arginine/serine-rich (RS) and RNA recognition motifs characteristic of PGC-1α1. Discrete functions for PGC-1α1 and -α4 have been described, but the biological role of PGC-1α2 and -α3 remains elusive. Here we show that different PGC-1α variants can affect target gene splicing through diverse mechanisms, including alternative promoter usage. By analyzing the exon structure of the target transcripts for each PGC-1α isoform, we were able to identify a large number of previously unknown PGC-1α2 and -α3 target genes and pathways in skeletal muscle. In particular, PGC-1α2 seems to mediate a decrease in the levels of cholesterol synthesis genes. Our results suggest that the conservation of the N-terminal activation and repression domains (and not the RS/RNA recognition motif) is what determines the gene programs and splicing options modulated by each PGC-1α isoform. By using skeletal muscle-specific transgenic mice for PGC-1α1 and -α4, we could validate, in vivo, splicing events observed in in vitro studies. These results show that alternative PGC-1α variants can affect target gene expression both quantitatively and qualitatively and identify novel biological pathways under the control of this system of coactivators.
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Affiliation(s)
- Vicente Martínez-Redondo
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Paulo R Jannig
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and School of Physical Education and Sport, University of São Paulo, 05508-030 São Paulo, Brazil, and
| | - Jorge C Correia
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Duarte M S Ferreira
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Igor Cervenka
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Jessica M Lindvall
- Department of Biosciences and Nutrition, Novum, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Indranil Sinha
- Department of Biosciences and Nutrition, Novum, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Manizheh Izadi
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Amanda T Pettersson-Klein
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Leandro Z Agudelo
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
| | - Alfredo Gimenez-Cassina
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Patricia C Brum
- School of Physical Education and Sport, University of São Paulo, 05508-030 São Paulo, Brazil, and
| | - Karin Dahlman-Wright
- Department of Biosciences and Nutrition, Novum, Karolinska Institutet, SE-141 83 Huddinge, Sweden
| | - Jorge L Ruas
- From the Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology Unit and
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34
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Escajadillo T, Wang H, Li L, Li D, Sewer MB. Oxysterol-related-binding-protein related Protein-2 (ORP2) regulates cortisol biosynthesis and cholesterol homeostasis. Mol Cell Endocrinol 2016; 427:73-85. [PMID: 26992564 PMCID: PMC4833515 DOI: 10.1016/j.mce.2016.03.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Revised: 03/04/2016] [Accepted: 03/04/2016] [Indexed: 12/30/2022]
Abstract
Oxysterol binding protein-related protein 2 (ORP2) is a lipid binding protein that has been implicated in various cellular processes, including lipid sensing, cholesterol efflux, and endocytosis. We recently identified ORP2 as a member of a protein complex that regulates glucocorticoid biosynthesis. Herein, we examine the effect of silencing ORP2 on adrenocortical function and show that the ORP2 knockdown cells exhibit reduced amounts of multiple steroid metabolites, including progesterone, 11-deoxycortisol, and cortisol, but have increased concentrations of androgens, and estrogens. Moreover, silencing ORP2 suppresses the expression of most proteins required for cortisol production and reduces the expression of steroidogenic factor 1 (SF1). ORP2 silencing also increases cellular cholesterol, concomitant with decreased amounts of 22-hydroxycholesterol and 7-ketocholesterol, two molecules that have been shown to bind to ORP2. Further, we show that ORP2 binds to liver X receptor (LXR) and is required for nuclear LXR expression. LXR and ORP2 are recruited to the CYP11B1 promoter in response to cAMP signaling. Additionally, ORP2 is required for the expression of other LXR target genes, including ABCA1 and the LDL receptor (LDLR). In summary, we establish a novel role for ORP2 in regulating steroidogenic capacity and cholesterol homeostasis in the adrenal cortex.
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Affiliation(s)
- Tamara Escajadillo
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA.
| | - Hongxia Wang
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Linda Li
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Donghui Li
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
| | - Marion B Sewer
- Skaggs School of Pharmacy & Pharmaceutical Sciences, University of California San Diego, La Jolla, CA, USA
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35
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Chiapparino A, Maeda K, Turei D, Saez-Rodriguez J, Gavin AC. The orchestra of lipid-transfer proteins at the crossroads between metabolism and signaling. Prog Lipid Res 2015; 61:30-9. [PMID: 26658141 DOI: 10.1016/j.plipres.2015.10.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 10/15/2015] [Indexed: 01/12/2023]
Abstract
Within the eukaryotic cell, more than 1000 species of lipids define a series of membranes essential for cell function. Tightly controlled systems of lipid transport underlie the proper spatiotemporal distribution of membrane lipids, the coordination of spatially separated lipid metabolic pathways, and lipid signaling mediated by soluble proteins that may be localized some distance away from membranes. Alongside the well-established vesicular transport of lipids, non-vesicular transport mediated by a group of proteins referred to as lipid-transfer proteins (LTPs) is emerging as a key mechanism of lipid transport in a broad range of biological processes. More than a hundred LTPs exist in humans and these can be divided into at least ten protein families. LTPs are widely distributed in tissues, organelles and membrane contact sites (MCSs), as well as in the extracellular space. They all possess a soluble and globular domain that encapsulates a lipid monomer and they specifically bind and transport a wide range of lipids. Here, we present the most recent discoveries in the functions and physiological roles of LTPs, which have expanded the playground of lipids into the aqueous spaces of cells.
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Affiliation(s)
- Antonella Chiapparino
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | - Kenji Maeda
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
| | - Denes Turei
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, D-69117 Heidelberg, Germany; European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute (EBI), Cambridge CB10 1SD, UK
| | - Julio Saez-Rodriguez
- European Molecular Biology Laboratory (EMBL), European Bioinformatics Institute (EBI), Cambridge CB10 1SD, UK
| | - Anne-Claude Gavin
- European Molecular Biology Laboratory (EMBL), Structural and Computational Biology Unit, Meyerhofstrasse 1, D-69117 Heidelberg, Germany; European Molecular Biology Laboratory (EMBL), Molecular Medicine Partnership Unit (MMPU), Meyerhofstrasse 1, D-69117 Heidelberg, Germany.
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36
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Olkkonen VM. OSBP-Related Protein Family in Lipid Transport Over Membrane Contact Sites. Lipid Insights 2015; 8:1-9. [PMID: 26715851 PMCID: PMC4685180 DOI: 10.4137/lpi.s31726] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/03/2015] [Accepted: 09/06/2015] [Indexed: 12/12/2022] Open
Abstract
Increasing evidence suggests that oxysterol-binding protein-related proteins (ORPs) localize at membrane contact sites, which are high-capacity platforms for inter-organelle exchange of small molecules and information. ORPs can simultaneously associate with the two apposed membranes and transfer lipids across the interbilayer gap. Oxysterol-binding protein moves cholesterol from the endoplasmic reticulum to trans-Golgi, driven by the retrograde transport of phosphatidylinositol-4-phosphate (PI4P). Analogously, yeast Osh6p mediates the transport of phosphatidylserine from the endoplasmic reticulum to the plasma membrane in exchange for PI4P, and ORP5 and -8 are suggested to execute similar functions in mammalian cells. ORPs may share the capacity to bind PI4P within their ligand-binding domain, prompting the hypothesis that bidirectional transport of a phosphoinositide and another lipid may be a common theme among the protein family. This model, however, needs more experimental support and does not exclude a function of ORPs in lipid signaling.
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Affiliation(s)
- Vesa M Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Helsinki, Finland. ; Department of Anatomy, Faculty of Medicine, University of Helsinki, Finland
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37
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Alasoo K, Martinez FO, Hale C, Gordon S, Powrie F, Dougan G, Mukhopadhyay S, Gaffney DJ. Transcriptional profiling of macrophages derived from monocytes and iPS cells identifies a conserved response to LPS and novel alternative transcription. Sci Rep 2015; 5:12524. [PMID: 26224331 PMCID: PMC4519778 DOI: 10.1038/srep12524] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 06/29/2015] [Indexed: 12/22/2022] Open
Abstract
Macrophages differentiated from human induced pluripotent stem cells (IPSDMs) are a potentially valuable new tool for linking genotype to phenotype in functional studies. However, at a genome-wide level these cells have remained largely uncharacterised. Here, we compared the transcriptomes of naïve and lipopolysaccharide (LPS) stimulated monocyte-derived macrophages (MDMs) and IPSDMs using RNA-Seq. The IPSDM and MDM transcriptomes were broadly similar and exhibited a highly conserved response to LPS. However, there were also significant differences in the expression of genes associated with antigen presentation and tissue remodelling. Furthermore, genes coding for multiple chemokines involved in neutrophil recruitment were more highly expressed in IPSDMs upon LPS stimulation. Additionally, analysing individual transcript expression identified hundreds of genes undergoing alternative promoter and 3' untranslated region usage following LPS treatment representing a previously under-appreciated level of regulation in the LPS response.
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Affiliation(s)
- Kaur Alasoo
- Wellcome Trust Sanger Institute, Hinxton, UK
| | | | | | - Siamon Gordon
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Fiona Powrie
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | | | - Subhankar Mukhopadhyay
- Wellcome Trust Sanger Institute, Hinxton, UK
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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38
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Alasoo K, Martinez FO, Hale C, Gordon S, Powrie F, Dougan G, Mukhopadhyay S, Gaffney DJ. Transcriptional profiling of macrophages derived from monocytes and iPS cells identifies a conserved response to LPS and novel alternative transcription. Sci Rep 2015. [PMID: 26224331 DOI: 10.1038/srep12524)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Macrophages differentiated from human induced pluripotent stem cells (IPSDMs) are a potentially valuable new tool for linking genotype to phenotype in functional studies. However, at a genome-wide level these cells have remained largely uncharacterised. Here, we compared the transcriptomes of naïve and lipopolysaccharide (LPS) stimulated monocyte-derived macrophages (MDMs) and IPSDMs using RNA-Seq. The IPSDM and MDM transcriptomes were broadly similar and exhibited a highly conserved response to LPS. However, there were also significant differences in the expression of genes associated with antigen presentation and tissue remodelling. Furthermore, genes coding for multiple chemokines involved in neutrophil recruitment were more highly expressed in IPSDMs upon LPS stimulation. Additionally, analysing individual transcript expression identified hundreds of genes undergoing alternative promoter and 3' untranslated region usage following LPS treatment representing a previously under-appreciated level of regulation in the LPS response.
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Affiliation(s)
- Kaur Alasoo
- Wellcome Trust Sanger Institute, Hinxton, UK
| | | | | | - Siamon Gordon
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Fiona Powrie
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
| | | | - Subhankar Mukhopadhyay
- 1] Wellcome Trust Sanger Institute, Hinxton, UK [2] Sir William Dunn School of Pathology, University of Oxford, Oxford, UK [3] Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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Weber-Boyvat M, Kentala H, Peränen J, Olkkonen VM. Ligand-dependent localization and function of ORP-VAP complexes at membrane contact sites. Cell Mol Life Sci 2015; 72:1967-87. [PMID: 25420878 PMCID: PMC11114005 DOI: 10.1007/s00018-014-1786-x] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 10/17/2014] [Accepted: 11/17/2014] [Indexed: 01/08/2023]
Abstract
Oxysterol-binding protein/OSBP-related proteins (ORPs) constitute a conserved family of sterol/phospholipid-binding proteins with lipid transporter or sensor functions. We investigated the spatial occurrence and regulation of the interactions of human OSBP/ORPs or the S. cerevisiae orthologs, the Osh (OSBP homolog) proteins, with their endoplasmic reticulum (ER) anchors, the VAMP-associated proteins (VAPs), by employing bimolecular fluorescence complementation and pull-down set-ups. The ORP-VAP interactions localize frequently at distinct subcellular sites, shown in several cases to represent membrane contact sites (MCSs). Using established ORP ligand-binding domain mutants and pull-down assays with recombinant proteins, we show that ORP liganding regulates the ORP-VAP association, alters the subcellular targeting of ORP-VAP complexes, or modifies organelle morphology. There is distinct protein specificity in the effects of the mutants on subcellular targeting of ORP-VAP complexes. We provide evidence that complexes of human ORP2 and VAPs at ER-lipid droplet interfaces regulate the hydrolysis of triglycerides and lipid droplet turnover. The data suggest evolutionarily conserved, complex ligand-dependent functions of ORP-VAP complexes at MCSs, with implications for cellular lipid homeostasis and signaling.
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Affiliation(s)
- Marion Weber-Boyvat
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Henriikka Kentala
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
| | - Johan Peränen
- Cell and Molecular Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Biomedicum 2U, Tukholmankatu 8, 00290 Helsinki, Finland
- Institute of Biomedicine, Anatomy, University of Helsinki, 00014 Helsinki, Finland
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40
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Un K, Sakai-Kato K, Kawanishi T, Okuda H, Goda Y. Effects of Liposomal Phospholipids and Lipid Transport-Related Protein on the Intracellular Fate of Encapsulated Doxorubicin. Mol Pharm 2014; 11:560-7. [DOI: 10.1021/mp400505a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Keita Un
- Division
of Drugs, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Kumiko Sakai-Kato
- Division
of Drugs, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Toru Kawanishi
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Haruhiro Okuda
- National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
| | - Yukihiro Goda
- Division
of Drugs, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan
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41
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Olkkonen VM, Li S. Oxysterol-binding proteins: Sterol and phosphoinositide sensors coordinating transport, signaling and metabolism. Prog Lipid Res 2013; 52:529-38. [DOI: 10.1016/j.plipres.2013.06.004] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/15/2013] [Accepted: 06/22/2013] [Indexed: 01/27/2023]
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42
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Vihervaara T, Käkelä R, Liebisch G, Tarasov K, Schmitz G, Olkkonen VM. Modification of the lipidome in RAW264.7 macrophage subjected to stable silencing of oxysterol-binding proteins. Biochimie 2013; 95:538-47. [DOI: 10.1016/j.biochi.2012.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/04/2012] [Indexed: 12/16/2022]
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43
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Siljamäki E, Rintanen N, Kirsi M, Upla P, Wang W, Karjalainen M, Ikonen E, Marjomäki V. Cholesterol dependence of collagen and echovirus 1 trafficking along the novel α2β1 integrin internalization pathway. PLoS One 2013; 8:e55465. [PMID: 23393580 PMCID: PMC3564754 DOI: 10.1371/journal.pone.0055465] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/23/2012] [Indexed: 12/29/2022] Open
Abstract
We have previously shown that soluble collagen and a human pathogen, echovirus 1 (EV1) cluster α2β1 integrin on the plasma membrane and cause their internalization into cytoplasmic endosomes. Here we show that cholesterol plays a major role not only in the uptake of α2β1 integrin and its ligands but also in the formation of α2 integrin-specific multivesicular bodies (α2-MVBs) and virus infection. EV1 infection and α2β1 integrin internalization were totally halted by low amounts of the cholesterol-aggregating drugs filipin or nystatin. Inhibition of cholesterol synthesis and accumulation of lanosterol after ketoconazole treatment inhibited uptake of collagen, virus and clustered integrin, and prevented formation of multivesicular bodies and virus infection. Loading of lipid starved cells with cholesterol increased infection to some extent but could not completely restore EV1 infection to control levels. Cold Triton X-100 treatment did not solubilize the α2-MVBs suggesting, together with cholesterol labeling, that the cytoplasmic endosomes were enriched in detergent-resistant lipids in contrast to αV integrin labeled control endosomes in the clathrin pathway. Cholesterol aggregation leading to increased ion permeability caused a significant reduction in EV1 uncoating in endosomes as judged by sucrose gradient centrifugation and by neutral red-based uncoating assay. In contrast, the replication step was not dependent on cholesterol in contrast to the reports on several other viruses. In conclusion, our results showed that the integrin internalization pathway is dependent on cholesterol for uptake of collagen, EV1 and integrin, for maturation of endosomal structures and for promoting EV1 uncoating. The results thus provide novel information for developing anti-viral strategies and more insight into collagen and integrin trafficking.
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Affiliation(s)
- Elina Siljamäki
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Nina Rintanen
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Maija Kirsi
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Paula Upla
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Wei Wang
- Institute of Biomedicine, University of Helsinki, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Mikko Karjalainen
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
| | - Elina Ikonen
- Institute of Biomedicine, University of Helsinki, Helsinki, Finland
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Varpu Marjomäki
- Department of Biological and Environmental Science/Nanoscience Center, University of Jyväskylä, Jyväskylä, Finland
- * E-mail:
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Un K, Sakai-Kato K, Oshima Y, Kawanishi T, Okuda H. Intracellular trafficking mechanism, from intracellular uptake to extracellular efflux, for phospholipid/cholesterol liposomes. Biomaterials 2012; 33:8131-41. [DOI: 10.1016/j.biomaterials.2012.07.030] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/15/2012] [Indexed: 01/27/2023]
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Zhou Y, Robciuc MR, Wabitsch M, Juuti A, Leivonen M, Ehnholm C, Yki-Järvinen H, Olkkonen VM. OSBP-related proteins (ORPs) in human adipose depots and cultured adipocytes: evidence for impacts on the adipocyte phenotype. PLoS One 2012; 7:e45352. [PMID: 23028956 PMCID: PMC3448648 DOI: 10.1371/journal.pone.0045352] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 08/15/2012] [Indexed: 01/28/2023] Open
Abstract
Oxysterol-binding protein (OSBP) homologues, ORPs, are implicated in lipid homeostatic control, vesicle transport, and cell signaling. We analyzed here the quantity of ORP mRNAs in human subcutaneous (s.c.) and visceral adipose depots, as well as in the Simpson-Golabi-Behmel syndrome (SGBS) adipocyte cell model. All of the ORP mRNAs were present in the s.c and visceral adipose tissues, and the two depots shared an almost identical ORP mRNA expression pattern. SGBS adipocytes displayed a similar pattern, suggesting that the adipose tissue ORP expression pattern mainly derives from adipocytes. During SGBS cell adipogenic differentiation, ORP2, ORP3, ORP4, ORP7, and ORP8 mRNAs were down-regulated, while ORP11 was induced. To assess the impacts of ORPs on adipocyte differentiation, ORP3 and ORP8, proteins down-regulated during adipogenesis, were overexpressed in differentiating SGBS adipocytes, while ORP11, a protein induced during adipogenesis, was silenced. ORP8 overexpression resulted in reduced expression of the aP2 mRNA, while down-regulation of adiponectin and aP2 was observed in ORP11 silenced cells. Furthermore, ORP8 overexpression or silencing of ORP11 markedly decreased cellular triglyceride storage. These data identify the patterns of ORP expression in human adipose depots and SGBS adipocytes, and provide the first evidence for a functional impact of ORPs on the adipocyte phenotype.
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Affiliation(s)
- You Zhou
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Marius R. Robciuc
- National Institute for Health and Welfare, Public Health Genomics Unit, Helsinki, Finland
| | - Martin Wabitsch
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany
| | - Anne Juuti
- Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Marja Leivonen
- Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Christian Ehnholm
- National Institute for Health and Welfare, Public Health Genomics Unit, Helsinki, Finland
| | - Hannele Yki-Järvinen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki, Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Institute of Biomedicine, Anatomy, University of Helsinki, Helsinki, Finland
- * E-mail:
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Nissilä E, Ohsaki Y, Weber-Boyvat M, Perttilä J, Ikonen E, Olkkonen VM. ORP10, a cholesterol binding protein associated with microtubules, regulates apolipoprotein B-100 secretion. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1472-84. [PMID: 22906437 DOI: 10.1016/j.bbalip.2012.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 07/31/2012] [Accepted: 08/03/2012] [Indexed: 12/30/2022]
Abstract
ORP10/OSBPL10 is a member of the oxysterol-binding protein family, and genetic variation in OSBPL10 is associated with dyslipidemias and peripheral artery disease. In this study we investigated the ligand binding properties of ORP10 in vitro as well as its localization and function in human HuH7 hepatocytes. The pleckstrin homology (PH) domain of ORP10 selectively interacts with phosphatidylinositol-4-phosphate, while the C-terminal ligand binding domain binds cholesterol and several acidic phospholipids. Full-length ORP10 decorates microtubules (MT), while the ORP10 N-terminal fragment (aa 1-318) localizes at Golgi membranes. Removal of the C-terminal aa 712-764 of ORP10 containing a predicted coiled-coil segment abolishes the MT association, but allows partial Golgi targeting. A PH domain-GFP fusion protein is distributed mainly in the cytosol and the plasma membrane, indicating that the Golgi affinity of ORP10 involves other determinants in addition to the PH domain. HuH7 cells expressing ORP10-specific shRNA display increased accumulation of apolipoprotein B-100 (apoB-100), but not of albumin, in culture medium, and contain reduced levels of intracellular apoB-100. Pulse-chase analysis of cellular [(35)S]apoB-100 demonstrates enhanced apoB-100 secretion by cells expressing ORP10-specific shRNA. The apoB-100 secretion phenotype is replicated in HepG2 cells transduced with the ORP10 shRNA lentiviruses. As a conclusion, the present study dissects the determinants of ORP10 association with MT and the Golgi complex and provides evidence for a specific role of this protein in β-lipoprotein secretion by human hepatocytes.
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Affiliation(s)
- Eija Nissilä
- Institute of Biomedicine, Anatomy, PO Box 63, FI-00014 University of Helsinki, Finland
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Abstract
The Kes1 OSBP (oxysterol-binding protein) is a key regulator of membrane trafficking through the TGN (trans-Golgi network) and endosomal membranes. We demonstrated recently that Kes1 acts as a sterol-regulated rheostat for TGN/endosomal phosphatidylinositol 4-phosphate signalling. Kes1 utilizes its dual lipid-binding activities to integrate endosomal lipid metabolism with TORC1 (target of rapamycin complex 1)-dependent proliferative pathways and transcriptional control of nutrient signalling.
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48
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Lee S, Wang PY, Jeong Y, Mangelsdorf DJ, Anderson RGW, Michaely P. Sterol-dependent nuclear import of ORP1S promotes LXR regulated trans-activation of apoE. Exp Cell Res 2012; 318:2128-42. [PMID: 22728266 DOI: 10.1016/j.yexcr.2012.06.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Revised: 05/30/2012] [Accepted: 06/08/2012] [Indexed: 01/30/2023]
Abstract
Oxysterol binding protein related protein 1S (ORP1S) is a member of a family of sterol transport proteins. Here we present evidence that ORP1S translocates from the cytoplasm to the nucleus in response to sterol binding. The sterols that best promote nuclear import of ORP1S also activate the liver X receptor (LXR) transcription factors and we show that ORP1S binds to LXRs, promotes binding of LXRs to LXR response elements (LXREs) and specifically enhances LXR-dependent transcription via the ME.1 and ME.2 enhancer elements of the apoE gene. We propose that ORP1S is a cytoplasmic sterol sensor, which transports sterols to the nucleus and promotes LXR-dependent gene transcription through select enhancer elements.
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Affiliation(s)
- Sungsoo Lee
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039, United States.
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Identification of novel host cell binding partners of Oas1b, the protein conferring resistance to flavivirus-induced disease in mice. J Virol 2012; 86:7953-63. [PMID: 22623793 DOI: 10.1128/jvi.00333-12] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Oas1b was previously identified as the product of the Flv(r) allele that confers flavivirus-specific resistance to virus-induced disease in mice by an uncharacterized, RNase L-independent mechanism. To gain insights about the mechanism by which Oas1b specifically reduces the efficiency of flavivirus replication, cellular protein interaction partners were identified and their involvement in the Oas1b-mediated flavivirus resistance mechanism was analyzed. Initial difficulties in getting the two-hybrid assay to work with full-length Oas1b led to the discovery that this Oas protein uniquely has a C-terminal transmembrane domain that targets it to the endoplasmic reticulum (ER). Two peptides matching to oxysterol binding protein-related protein 1L (ORP1L) and ATP binding cassette protein 3, subfamily F (ABCF3), were identified as Oas1b interaction partners in yeast two-hybrid assays, and both in vitro-transcribed/translated peptides and full-length proteins in mammalian cell lysates coimmunoprecipitated with Oas1b. Knockdown of a partner involved in Oas1b-mediated antiflavivirus activity would be expected to increase flavivirus replication but not that of other types of viruses. However, RNA interference (RNAi) knockdown of ORP1L decreased the replication of the flavivirus West Nile virus (WNV) as well as that of other types of RNA viruses. This virus-nonspecific effect may be due to the recently reported dysregulation of late endosome movement by ORP1L knockdown. Knockdown of ABCF3 protein levels increased the replication of WNV but not that of other types of RNA viruses, and this effect on WNV replication was observed only in Oas1b-expressing cells. The results suggest that Oas1b is part of a complex located in the ER and that ABCF3 is a component of the Flv(r)-mediated resistance mechanism.
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50
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Olkkonen VM, Zhou Y, Yan D, Vihervaara T. Oxysterol-binding proteins-emerging roles in cell regulation. EUR J LIPID SCI TECH 2012. [DOI: 10.1002/ejlt.201200044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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