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Kita N, Hamamoto A, Gowda SGB, Takatsu H, Nakayama K, Arita M, Hui SP, Shin HW. Glucosylceramide flippases contribute to cellular glucosylceramide homeostasis. J Lipid Res 2024; 65:100508. [PMID: 38280458 PMCID: PMC10910339 DOI: 10.1016/j.jlr.2024.100508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/18/2024] [Accepted: 01/19/2024] [Indexed: 01/29/2024] Open
Abstract
Lipid transport is an essential cellular process with importance to human health, disease development, and therapeutic strategies. Type IV P-type ATPases (P4-ATPases) have been identified as membrane lipid flippases by utilizing nitrobenzoxadiazole (NBD)-labeled lipids as substrates. Among the 14 human type IV P-type ATPases, ATP10D was shown to flip NBD-glucosylceramide (GlcCer) across the plasma membrane. Here, we found that conversion of incorporated GlcCer (d18:1/12:0) to other sphingolipids is accelerated in cells exogenously expressing ATP10D but not its ATPase-deficient mutant. These findings suggest that 1) ATP10D flips unmodified GlcCer as well as NBD-GlcCer at the plasma membrane and 2) ATP10D can translocate extracellular GlcCer, which is subsequently converted to other metabolites. Notably, exogenous expression of ATP10D led to the reduction in cellular hexosylceramide levels. Moreover, the expression of GlcCer flippases, including ATP10D, also reduced cellular hexosylceramide levels in fibroblasts derived from patients with Gaucher disease, which is a lysosomal storage disorder with excess GlcCer accumulation. Our study highlights the contribution of ATP10D to the regulation of cellular GlcCer levels and maintaining lipid homeostasis.
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Affiliation(s)
- Natsuki Kita
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Asuka Hamamoto
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Siddabasave Gowda B Gowda
- Faculty of Health Sciences, Hokkaido University, Sapporo, Japan; Graduate School of Global Food Resources, Hokkaido University, Sapporo, Japan
| | - Hiroyuki Takatsu
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Makoto Arita
- Laboratory for Metabolomics, RIKEN Center of Integrative Medical Sciences, Yokohama, Japan
| | - Shu-Ping Hui
- Faculty of Health Sciences, Hokkaido University, Sapporo, Japan
| | - Hye-Won Shin
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan.
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2
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Nurmi H, Backman AE, Halin J, Lönnfors M, Blom T, Roos-Mattjus P, Mattjus P. Glycolipid transfer protein knockout disrupts vesicle trafficking to the plasma membrane. J Biol Chem 2023; 299:104607. [PMID: 36924944 PMCID: PMC10140181 DOI: 10.1016/j.jbc.2023.104607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 02/16/2023] [Accepted: 03/06/2023] [Indexed: 03/17/2023] Open
Abstract
The glycolipid transfer protein (GLTP) has been linked to many cellular processes aside from its best-known in vitro function as a lipid transport protein. It has been proposed to act as a sensor and regulator of glycosphingolipid homeostasis in cells. Furthermore, through its previously determined interaction with the endoplasmic reticulum (ER) membrane protein VAP-A (vesicle-associated membrane protein-associated protein A), GLTP may also be involved in facilitating vesicular transport in cells. In this study, we characterized the phenotype of CRISPR/Cas9-mediated GLTP knockout HeLa cells. We showed that motility, three-dimensional growth, and cellular metabolism were all altered by GLTP knockout. Expression of a GLTP mutant incapable of binding VAP disrupted cell spheroid formation, indicating that the GLTP-VAP interaction is linked to cellular adhesion, cohesion, and three-dimensional growth. Most notably, we found evidence that GLTP, through its interaction with VAP-A, affects vesicular trafficking, marking the first cellular process discovered to be directly impacted by a change in GLTP expression.
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Affiliation(s)
- Henrik Nurmi
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland
| | - AndersP E Backman
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland
| | - Josefin Halin
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland
| | - Max Lönnfors
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland
| | - Tomas Blom
- Department of Anatomy and Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Pia Roos-Mattjus
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland
| | - Peter Mattjus
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6A, III, 20520 Turku, Finland.
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3
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Kors S, Costello JL, Schrader M. VAP Proteins - From Organelle Tethers to Pathogenic Host Interactors and Their Role in Neuronal Disease. Front Cell Dev Biol 2022; 10:895856. [PMID: 35756994 PMCID: PMC9213790 DOI: 10.3389/fcell.2022.895856] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 12/26/2022] Open
Abstract
Vesicle-associated membrane protein (VAMP)-associated proteins (VAPs) are ubiquitous ER-resident tail-anchored membrane proteins in eukaryotic cells. Their N-terminal major sperm protein (MSP) domain faces the cytosol and allows them to interact with a wide variety of cellular proteins. Therefore, VAP proteins are vital to many cellular processes, including organelle membrane tethering, lipid transfer, autophagy, ion homeostasis and viral defence. Here, we provide a timely overview of the increasing number of VAPA/B binding partners and discuss the role of VAPA/B in maintaining organelle-ER interactions and cooperation. Furthermore, we address how viruses and intracellular bacteria hijack VAPs and their binding partners to induce interactions between the host ER and pathogen-containing compartments and support pathogen replication. Finally, we focus on the role of VAP in human disease and discuss how mutated VAPB leads to the disruption of cellular homeostasis and causes amyotrophic lateral sclerosis.
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Affiliation(s)
- Suzan Kors
- *Correspondence: Suzan Kors, ; Michael Schrader,
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4
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Backman APE, Mattjus P. Who moves the sphinx? An overview of intracellular sphingolipid transport. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159021. [PMID: 34339859 DOI: 10.1016/j.bbalip.2021.159021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/24/2021] [Accepted: 06/27/2021] [Indexed: 11/28/2022]
Abstract
Lipid bilayers function as boundaries that enclose their content from the surrounding media, and the composition of different membrane types is accurately and dynamically tailored so that they can perform their function. To achieve this balance, lipid biosynthetic machinery and lipid trafficking events are intertwined into an elegant network. In this review, we focus on the intracellular movement of sphingolipids mediated by sphingolipid transfer proteins. Additionally, we will focus on the best characterized and understood mammalian sphingolipid transfer proteins and provide an overview of how they are hypothesized to function. Some are already well understood, while others remain enigmatic. A few are actual lipid transfer proteins, moving lipids from membrane to membrane, while others may have more of a sensor role, possibly reacting to changes in the concentrations of their ligands. Considering the substrates available for cytosolic sphingolipid transfer proteins, one open question that is discussed is whether galactosylceramide is a target. Another question is the exact mechanics by which sphingolipid transfer proteins are targeted to different organelles, such as how four phosphate adapter protein-2, FAPP2 is targeted to the endoplasmic reticulum. The aim of this review is to discuss what is known within the field today and to provide a basic understanding of how these proteins may work.
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Affiliation(s)
- Anders P E Backman
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Peter Mattjus
- Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland.
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Mishra SK, Gao YG, Zou X, Stephenson DJ, Malinina L, Hinchcliffe EH, Chalfant CE, Brown RE. Emerging roles for human glycolipid transfer protein superfamily members in the regulation of autophagy, inflammation, and cell death. Prog Lipid Res 2020; 78:101031. [PMID: 32339554 DOI: 10.1016/j.plipres.2020.101031] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/27/2020] [Accepted: 02/27/2020] [Indexed: 12/14/2022]
Abstract
Glycolipid transfer proteins (GLTPs) were first identified over three decades ago as ~24kDa, soluble, amphitropic proteins that specifically accelerate the intermembrane transfer of glycolipids. Upon discovery that GLTPs use a unique, all-α-helical, two-layer 'sandwich' architecture (GLTP-fold) to bind glycosphingolipids (GSLs), a new protein superfamily was born. Structure/function studies have provided exquisite insights defining features responsible for lipid headgroup selectivity and hydrophobic 'pocket' adaptability for accommodating hydrocarbon chains of differing length and unsaturation. In humans, evolutionarily-modified GLTP-folds have been identified with altered sphingolipid specificity, e. g. ceramide-1-phosphate transfer protein (CPTP), phosphatidylinositol 4-phosphate adaptor protein-2 (FAPP2) which harbors a GLTP-domain and GLTPD2. Despite the wealth of structural data (>40 Protein Data Bank deposits), insights into the in vivo functional roles of GLTP superfamily members have emerged slowly. In this review, recent advances are presented and discussed implicating human GLTP superfamily members as important regulators of: i) pro-inflammatory eicosanoid production associated with Group-IV cytoplasmic phospholipase A2; ii) autophagy and inflammasome assembly that drive surveillance cell release of interleukin-1β and interleukin-18 inflammatory cytokines; iii) cell cycle arrest and necroptosis induction in certain colon cancer cell lines. The effects exerted by GLTP superfamily members appear linked to their ability to regulate sphingolipid homeostasis by acting in either transporter and/or sensor capacities. These timely findings are opening new avenues for future cross-disciplinary, translational medical research involving GLTP-fold proteins in human health and disease. Such avenues include targeted regulation of specific GLTP superfamily members to alter sphingolipid levels as a therapeutic means for combating viral infection, neurodegenerative conditions and circumventing chemo-resistance during cancer treatment.
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Affiliation(s)
- Shrawan K Mishra
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yong-Guang Gao
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Xianqiong Zou
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Daniel J Stephenson
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0614, USA; Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA
| | - Lucy Malinina
- Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | | | - Charles E Chalfant
- Department of Cell Biology, Microbiology and Molecular Biology, University of South Florida, Tampa, FL 33620, USA; Research Service, James A. Haley Veterans Hospital, Tampa, FL 33612, USA; The Moffitt Cancer Center, Tampa, FL 33620, USA
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6
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Huang MH, Li H, Xue R, Li J, Wang L, Cheng J, Wu Z, Li W, Chen J, Lv X, Li Q, Lan P, Zhao L, Yang Y, Peng Z, Jiang J. Up-regulation of glycolipid transfer protein by bicyclol causes spontaneous restriction of hepatitis C virus replication. Acta Pharm Sin B 2019; 9:769-781. [PMID: 31384537 PMCID: PMC6663943 DOI: 10.1016/j.apsb.2019.01.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/07/2018] [Accepted: 01/22/2019] [Indexed: 12/21/2022] Open
Abstract
Bicyclol is a synthetic drug for hepatoprotection in clinic since 2004. Preliminary clinical observations suggest that bicyclol might be active against hepatitis C virus (HCV) with unknown mechanism. Here, we showed that bicyclol significantly inhibited HCV replication in vitro and in hepatitis C patients. Using bicyclol as a probe, we identified glycolipid transfer protein (GLTP) to be a novel restrictive factor for HCV replication. The GLTP preferentially bound host vesicle-associated membrane protein-associated protein-A (VAP-A) in competition with the HCV NS5A, causing an interruption of the complex formation between VAP-A and HCV NS5A. As the formation of VAP-A/NS5A complex is essential for viral RNA replication, up-regulation of GLTP by bicyclol reduced the level of VAP-A/NS5A complex and thus inhibited HCV replication. Bicyclol also exhibited an inhibition on HCV variants resistant to direct-acting antiviral agents (DAAs) with an efficacy identical to that on wild type HCV. In combination with bicyclol, DAAs inhibited HCV replication in a synergistic fashion. GLTP appears to be a newly discovered host restrictive factor for HCV replication, Up-regulation of GLTP causes spontaneous restriction of HCV replication.
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Affiliation(s)
- Meng-Hao Huang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Hu Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Rong Xue
- Department of Liver Diseases, the Second Hospital of Nanjing, Southeast University, Nanjing 210003, China
| | - Jianrui Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Lihua Wang
- Department of Liver Diseases, the Second Hospital of Nanjing, Southeast University, Nanjing 210003, China
| | - Junjun Cheng
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Zhouyi Wu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Wenjing Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Jinhua Chen
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Xiaoqin Lv
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Qiang Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Pei Lan
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Limin Zhao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
| | - Yongfeng Yang
- Department of Liver Diseases, the Second Hospital of Nanjing, Southeast University, Nanjing 210003, China
- Corresponding authors.
| | - Zonggen Peng
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
- Corresponding authors.
| | - Jiandong Jiang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100050, China
- Corresponding authors.
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7
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Backman APE, Halin J, Kjellberg MA, Mattjus P. Indirect Lipid Transfer Protein Activity Measurements Using Quantification of Glycosphingolipid Production. Methods Mol Biol 2019; 1949:105-114. [PMID: 30790252 DOI: 10.1007/978-1-4939-9136-5_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Here we summarize how glycosphingolipid production can be followed using metabolic labeling with radiolabeled lipid precursors. No assays are available yet that directly would address the lipid transfer protein activity in vivo. Therefore, these approaches can serve as tools to indirectly study the lipid transfer protein activity in cells, by monitoring their impact on the glycosphingolipid homeostasis.
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Affiliation(s)
- Anders P E Backman
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Turku, Finland
| | - Josefin Halin
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Turku, Finland
| | - Matti A Kjellberg
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Turku, Finland
| | - Peter Mattjus
- Faculty of Science and Engineering, Biochemistry, Åbo Akademi University, Turku, Finland.
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8
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Glucosylceramide acyl chain length is sensed by the glycolipid transfer protein. PLoS One 2018; 13:e0209230. [PMID: 30550553 PMCID: PMC6294359 DOI: 10.1371/journal.pone.0209230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/30/2018] [Indexed: 12/02/2022] Open
Abstract
The glycolipid transfer protein, GLTP, can be found in the cytoplasm, and it has a FFAT-like motif (two phenylalanines in an acidic tract) that targets it to the endoplasmic reticulum (ER). We have previously shown that GLTP can bind to a transmembrane ER protein, vesicle-associated membrane protein-associated protein A (VAP-A), which is involved in a wide range of ER functions. We have addressed the mechanisms that might regulate the association between GLTP and the VAP proteins by studying the capacity of GLTP to recognize different N-linked acyl chain species of glucosylceramide. We used surface plasmon resonance and a lipid transfer competition assay to show that GLTP prefers shorter N-linked fully saturated acyl chain glucosylceramides, such as C8, C12, and C16, whereas long C18, C20, and C24-glucosylceramides are all bound more weakly and transported more slowly than their shorter counterparts. Changes in the intrinsic GLTP tryptophan fluorescence blueshifts, also indicate a break-point between C16- and C18-glucosylceramide in the GLTP sensing ability. It has long been postulated that GLTP would be a sensor in the sphingolipid synthesis machinery, but how this mechanistically occurs has not been addressed before. It is unclear what proteins the GLTP VAP association would influence. Here we found that if GLTP has a bound GlcCer the association with VAP-A is weaker. We have also used a formula for identifying putative FFAT-domains, and we identified several potential VAP-interactors within the ceramide and sphingolipid synthesis pathways that could be candidates for regulation by GLTP.
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Ochoa-Lizarralde B, Gao YG, Popov AN, Samygina VR, Zhai X, Mishra SK, Boldyrev IA, Molotkovsky JG, Simanshu DK, Patel DJ, Brown RE, Malinina L. Structural analyses of 4-phosphate adaptor protein 2 yield mechanistic insights into sphingolipid recognition by the glycolipid transfer protein family. J Biol Chem 2018; 293:16709-16723. [PMID: 30206120 DOI: 10.1074/jbc.ra117.000733] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 08/22/2018] [Indexed: 01/25/2023] Open
Abstract
The glycolipid transfer protein (GLTP) fold defines a superfamily of eukaryotic proteins that selectively transport sphingolipids (SLs) between membranes. However, the mechanisms determining the protein selectivity for specific glycosphingolipids (GSLs) are unclear. Here, we report the crystal structure of the GLTP homology (GLTPH) domain of human 4-phosphate adaptor protein 2 (FAPP2) bound with N-oleoyl-galactosylceramide. Using this domain, FAPP2 transports glucosylceramide from its cis-Golgi synthesis site to the trans-Golgi for conversion into complex GSLs. The FAPP2-GLTPH structure revealed an element, termed the ID loop, that controls specificity in the GLTP family. We found that, in accordance with FAPP2 preference for simple GSLs, the ID loop protrudes from behind the SL headgroup-recognition center to mitigate binding by complex GSLs. Mutational analyses including GLTP and FAPP2 chimeras with swapped ID loops supported the proposed restrictive role of the FAPP2 ID loop in GSL selectivity. Comparative analysis revealed distinctly designed ID loops in each GLTP family member. This analysis also disclosed a conserved H-bond triplet that "clasps" both ID-loop ends together to promote structural autonomy and rigidity. The findings indicated that various ID loops work in concert with conserved recognition centers to create different specificities among family members. We also observed four bulky, conserved hydrophobic residues involved in "sensor-like" interactions with lipid chains in protein hydrophobic pockets and FF motifs in GLTP and FAPP2, well-positioned to provide acyl chain-dependent SL selectivity for the hydrophobic pockets. In summary, our study provides mechanistic insights into sphingolipid recognition by the GLTP fold and uncovers the elements involved in this recognition.
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Affiliation(s)
- Borja Ochoa-Lizarralde
- From the Structural Biology Unit of CIC bioGUNE, Technology Park of Bizkaia, 48160 Derio, Spain
| | - Yong-Guang Gao
- the Hormel Institute, University of Minnesota, Austin, Minnesota 55912
| | | | - Valeria R Samygina
- From the Structural Biology Unit of CIC bioGUNE, Technology Park of Bizkaia, 48160 Derio, Spain.,the Shubnikov Institute of Crystallography of FSRC Crystallography and Photonics RAS, 119333 Moscow, Russia
| | - Xiuhong Zhai
- the Hormel Institute, University of Minnesota, Austin, Minnesota 55912
| | - Shrawan K Mishra
- the Hormel Institute, University of Minnesota, Austin, Minnesota 55912
| | - Ivan A Boldyrev
- the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia, and
| | - Julian G Molotkovsky
- the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry RAS, 117997 Moscow, Russia, and
| | - Dhirendra K Simanshu
- the Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
| | - Dinshaw J Patel
- the Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021
| | - Rhoderick E Brown
- the Hormel Institute, University of Minnesota, Austin, Minnesota 55912,
| | - Lucy Malinina
- From the Structural Biology Unit of CIC bioGUNE, Technology Park of Bizkaia, 48160 Derio, Spain, .,the Hormel Institute, University of Minnesota, Austin, Minnesota 55912
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10
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Yadav S, Thakur R, Georgiev P, Deivasigamani S, Krishnan H, Ratnaparkhi G, Raghu P. RDGBα localization and function at membrane contact sites is regulated by FFAT-VAP interactions. J Cell Sci 2018; 131:jcs.207985. [PMID: 29180517 DOI: 10.1242/jcs.207985] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/20/2017] [Indexed: 12/27/2022] Open
Abstract
Phosphatidylinositol transfer proteins (PITPs) are essential regulators of PLC signalling. The PI transfer domain (PITPd) of multi-domain PITPs is reported to be sufficient for in vivo function, questioning the relevance of other domains in the protein. In Drosophila photoreceptors, loss of RDGBα, a multi-domain PITP localized to membrane contact sites (MCSs), results in multiple defects during PLC signalling. Here, we report that the PITPd of RDGBα does not localize to MCSs and fails to support function during strong PLC stimulation. We show that the MCS localization of RDGBα depends on the interaction of its FFAT motif with dVAP-A. Disruption of the FFAT motif (RDGBFF/AA) or downregulation of dVAP-A, both result in mis-localization of RDGBα and are associated with loss of function. Importantly, the ability of the PITPd in full-length RDGBFF/AA to rescue mutant phenotypes was significantly worse than that of the PITPd alone, indicating that an intact FFAT motif is necessary for PITPd activity in vivo Thus, the interaction between the FFAT motif and dVAP-A confers not only localization but also intramolecular regulation on lipid transfer by the PITPd of RDGBα. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Shweta Yadav
- Cellular Organization and Signalling, National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Rajan Thakur
- Cellular Organization and Signalling, National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India.,Shanmugha Arts, Science, Technology & Research Academy, Thanjavur 613401, India
| | - Plamen Georgiev
- Inositide Laboratory, Babraham Institute, Cambridge CB22 3AT, UK
| | | | - Harini Krishnan
- Cellular Organization and Signalling, National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Girish Ratnaparkhi
- Department of Biology, Indian Institute of Science Education and Research, Pune 411021, India
| | - Padinjat Raghu
- Cellular Organization and Signalling, National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
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VAP, a Versatile Access Point for the Endoplasmic Reticulum: Review and analysis of FFAT-like motifs in the VAPome. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:952-961. [PMID: 26898182 DOI: 10.1016/j.bbalip.2016.02.009] [Citation(s) in RCA: 212] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 02/12/2016] [Accepted: 02/12/2016] [Indexed: 11/24/2022]
Abstract
Dysfunction of VAMP-associated protein (VAP) is associated with neurodegeneration, both Amyotrophic Lateral Sclerosis and Parkinson's disease. Here we summarize what is known about the intracellular interactions of VAP in humans and model organisms. VAP is a simple, small and highly conserved protein on the cytoplasmic face of the endoplasmic reticulum (ER). It is the sole protein on that large organelle that acts as a receptor for cytoplasmic proteins. This may explain the extremely wide range of interacting partners of VAP, with components of many cellular pathways binding it to access the ER. Many proteins that bind VAP also target other intracellular membranes, so VAP is a component of multiple molecular bridges at membrane contact sites between the ER and other organelles. So far approximately 100 proteins have been identified in the VAP interactome (VAPome), of which a small minority have a "two phenylalanines in an acidic tract" (FFAT) motif as it was originally defined. We have analyzed the entire VAPome in humans and yeast using a simple algorithm that identifies many more FFAT-like motifs. We show that approximately 50% of the VAPome binds directly or indirectly via the VAP-FFAT interaction. We also review evidence on pathogenesis in genetic disorders of VAP, which appear to arise from reduced overall VAP levels, leading to ER stress. It is not possible to identify one single interaction that underlies disease. This article is part of a Special Issue entitled: The cellular lipid landscape edited by Tim P. Levine and Anant K. Menon.
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12
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Malinina L, Simanshu DK, Zhai X, Samygina VR, Kamlekar R, Kenoth R, Ochoa-Lizarralde B, Malakhova ML, Molotkovsky JG, Patel DJ, Brown RE. Sphingolipid transfer proteins defined by the GLTP-fold. Q Rev Biophys 2015; 48:281-322. [PMID: 25797198 PMCID: PMC4691851 DOI: 10.1017/s003358351400016x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Glycolipid transfer proteins (GLTPs) originally were identified as small (~24 kDa), soluble, amphitropic proteins that specifically accelerate the intermembrane transfer of glycolipids. GLTPs and related homologs now are known to adopt a unique, helically dominated, two-layer 'sandwich' architecture defined as the GLTP-fold that provides the structural underpinning for the eukaryotic GLTP superfamily. Recent advances now provide exquisite insights into structural features responsible for lipid headgroup selectivity as well as the adaptability of the hydrophobic compartment for accommodating hydrocarbon chains of differing length and unsaturation. A new understanding of the structural versatility and evolutionary premium placed on the GLTP motif has emerged. Human GLTP-motifs have evolved to function not only as glucosylceramide binding/transferring domains for phosphoinositol 4-phosphate adaptor protein-2 during glycosphingolipid biosynthesis but also as selective binding/transfer proteins for ceramide-1-phosphate. The latter, known as ceramide-1-phosphate transfer protein, recently has been shown to form GLTP-fold while critically regulating Group-IV cytoplasmic phospholipase A2 activity and pro-inflammatory eicosanoid production.
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Affiliation(s)
- Lucy Malinina
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
- Structural Biology Unit, CICbioGUNE, Technology Park of Bizkaia, 48160 Derio-Bilbao, Spain
| | - Dhirendra K. Simanshu
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Xiuhong Zhai
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Valeria R. Samygina
- Structural Biology Unit, CICbioGUNE, Technology Park of Bizkaia, 48160 Derio-Bilbao, Spain
| | | | - Roopa Kenoth
- The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Borja Ochoa-Lizarralde
- Structural Biology Unit, CICbioGUNE, Technology Park of Bizkaia, 48160 Derio-Bilbao, Spain
| | | | - Julian G. Molotkovsky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Dinshaw J. Patel
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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Ichikawa M, Nakai Y, Arima K, Nishiyama S, Hirano T, Sato MH. A VAMP-associated protein, PVA31 is involved in leaf senescence in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2015; 10:e990847. [PMID: 25897470 PMCID: PMC4622063 DOI: 10.4161/15592324.2014.990847] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 10/14/2014] [Accepted: 10/15/2014] [Indexed: 05/26/2023]
Abstract
VAMP-associated proteins (VAPs) are highly conserved among eukaryotes. Here, we report a functional analysis of one of the VAPs, PVA31, and demonstrate its novel function on leaf senescence in Arabidopsis. The expression of PVA31 is highly induced in senescence leaves, and localizes to the plasma membrane as well as the ARA7-positive endosomes. Yeast two-hybrid analysis demonstrates that PVA31 is interacted with the plasma membrane localized-VAMP proteins, VAMP721/722/724 but not with the endosome-localized VAMPs, VAMP711 and VAMP727, indicating that PVA31 is associated with VAMP721/722/724 on the plasma membrane. Strong constitutive expression of PVA31 under the control of the Cauliflower mosaic virus 35S promoter induces the typical symptom of leaf senescence earlier than WT in normal growth and an artificially induced senescence conditions. In addition, the marker genes for the SA-mediated signaling pathways, PR-1, is promptly expressed with elicitor application. These data indicate that PVA31-overexpressing plants exhibit the early senescence phenotype in their leaves, and suggest that PVA31 is involved in the SA-mediated programmed cell death process during leaf senescence and PR-protein secretion during pathogen infection in Arabidopsis.
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Affiliation(s)
- Mie Ichikawa
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
| | - Yusuke Nakai
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
- Current affiliation: Research Institute of Genome-based Biofactory; AIST; Tsukuba, Japan
| | - Keita Arima
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
| | - Sayo Nishiyama
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
| | - Tomoko Hirano
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
| | - Masa H Sato
- Graduate School of Life and Environmental Sciences; Kyoto Prefectural University; Kyoto, Japan
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Kjellberg MA, Backman APE, Ohvo-Rekilä H, Mattjus P. Alternation in the glycolipid transfer protein expression causes changes in the cellular lipidome. PLoS One 2014; 9:e97263. [PMID: 24824606 PMCID: PMC4019525 DOI: 10.1371/journal.pone.0097263] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/16/2014] [Indexed: 01/24/2023] Open
Abstract
The glycolipid transfer protein (GLTP) catalyzes the binding and transport of glycolipids, but not phospholipids or neutral lipids. With its all-alpha helical fold, it is the founding member for a new superfamily, however its biological role still remains unclear. We have analyzed changes in the HeLa cell lipidome in response to down- and up-regulation of GLTP expression. We used metabolic labeling and thin layer chromatography analysis, complemented with a lipidomics mass spectroscopic approach. HeLa cells were treated with GLTP siRNA or were transiently overexpressing the GLTP gene. We identified eight different lipid classes that changed as a result of the GLTP down- or up-regulation treatments; glucosylceramide, lactosylceramide, globotriaosylceramide, ceramide, sphingomyelin, cholesterol-esters, diacylglycerol and phosphatidylserine. We discovered that the amount of globotriaosylceramide (Gb3) was extensively lowered after down-regulation of GLTP. Further, an up-regulation of GLTP caused a substantial increase in both the Gb3 and glucosylceramide levels compared to the controls. Total galactosylceramide levels remained unchanged. Both lactosylceramide and ceramide showed small changes, an increase with increasing GLTP and a decrease in the HeLa cell GLTP knockdowns. The cholesterol-esters and diacylglycerol masses increased in cells that had upregulated GLTP protein levels, wheras down-regulation did not affect their amounts. For the glycerophospholipids, phosphatidylserine was the only species that was lower in GLTP overexpressing cells. Phosphatidylethanolamine, phosphatidylglyerol and phosphatidylinositol remained unaltered. A total of 142 lipid species were profiled and quantified using shotgun lipidomics analyses. This work provides for the first time insights into how alternations in the levels of a protein that binds and transfers glycolipids affects the cellular lipid metabolism. We discuss the observed changes in the lipidome and how these relate to GLTP. We suggest, that GLTP not only could be a significant player in cellular sphingolipid metabolism, but also could have a much broader role in the overall lipid metabolism.
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Affiliation(s)
- Matti A. Kjellberg
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | | | - Henna Ohvo-Rekilä
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Peter Mattjus
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
- * E-mail:
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15
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Tuuf J, Mattjus P. Membranes and mammalian glycolipid transferring proteins. Chem Phys Lipids 2013; 178:27-37. [PMID: 24220498 DOI: 10.1016/j.chemphyslip.2013.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 10/29/2013] [Accepted: 10/30/2013] [Indexed: 01/04/2023]
Abstract
Glycolipids are synthesized in and on various organelles throughout the cell. Their trafficking inside the cell is complex and involves both vesicular and protein-mediated machineries. Most important for the bulk lipid transport is the vesicular system, however, lipids moved by transfer proteins are also becoming more characterized. Here we review the latest advances in the glycolipid transfer protein (GLTP) and the phosphoinositol 4-phosphate adaptor protein-2 (FAPP2) field, from a membrane point of view.
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Affiliation(s)
- Jessica Tuuf
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
| | - Peter Mattjus
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland.
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16
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Kjellberg MA, Mattjus P. Glycolipid transfer protein expression is affected by glycosphingolipid synthesis. PLoS One 2013; 8:e70283. [PMID: 23894633 PMCID: PMC3722133 DOI: 10.1371/journal.pone.0070283] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 06/19/2013] [Indexed: 11/25/2022] Open
Abstract
Members of the glycolipid transfer protein superfamily (GLTP) are found from animals and fungi to plants and red micro-alga. Eukaryotes that encode the glucosylceramide synthase responsible for the synthesis of glucosylceramide, the precursor for most glycosphingolipids, also produce GLTPs. Cells that does not synthesize glucosylceramide neither express GLTPs. Based on this genetic relationship there must be a strong correlation between the synthesis of glucosylceramide and GLTPs. To regulate the levels of glycolipids we have used inhibitors of intracellular trafficking, glycosphingolipid synthesis and degradation, and small interfering RNA to down-regulate the activity of glucosylceramide synthase activity. We found that GLTP expression, both at the mRNA and protein levels, is elevated in cells that accumulate glucosylceramide. Monensin and brefeldin A block intracellular vesicular transport mechanisms. Brefeldin A treatment leads to accumulation of newly synthesized glucosylceramide, galactosylceramide and lactosylceramide in a fused endoplasmic reticulum-Golgi complex. On the other hand, inhibiting glycosphingolipid degradation with conduritol-B-epoxide, that generates glucosylceramide accumulation in the lysosomes, did not affect the levels of GLTP. However, glycosphingolipid synthesis inhibitors like PDMP, NB-DNJ and myriocin, all decreased glucosylceramide and GLTP below normal levels. We also found that an 80% loss of glucosylceramide due to glucosylceramide synthase knockdown resulted in a significant reduction in the expression of GLTP. We show here that interfering with membrane trafficking events and simple neutral glycosphingolipid synthesis will affect the expression of GLTP. We postulate that a change in the glucosylceramide balance causes a response in the GLTP expression, and put forward that GLTP might play a role in lipid directing and sensing of glucosylceramide at the ER-Golgi interface.
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Affiliation(s)
- Matti A Kjellberg
- Biochemistry, Department of Biosciences, Åbo Akademi University, Turku, Finland
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Hanada K. Co-evolution of sphingomyelin and the ceramide transport protein CERT. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:704-19. [PMID: 23845852 DOI: 10.1016/j.bbalip.2013.06.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 06/25/2013] [Accepted: 06/25/2013] [Indexed: 12/15/2022]
Abstract
Life creates many varieties of lipids. The choline-containing sphingophospholipid sphingomyelin (SM) exists ubiquitously or widely in vertebrates and lower animals, but is absent or rare in bacteria, fungi, protists, and plants. In the biosynthesis of SM, ceramide, which is synthesized in the endoplasmic reticulum, is transported to the Golgi region by the ceramide transport protein CERT, probably in a non-vesicular manner, and is then converted to SM by SM synthase, which catalyzes the reaction of phosphocholine transfer from phosphatidylcholine (PtdCho) to ceramide. Recent advances in genomics and lipidomics indicate that the phylogenetic occurrence of CERT and its orthologs is nearly parallel to that of SM. Based on the chemistry of lipids together with evolutionary aspects of SM and CERT, several concepts are here proposed. SM may serve as a chemically inert and robust, but non-covalently interactive lipid class at the outer leaflet of the plasma membrane. The functional domains and peptidic motifs of CERT are separated by exon units, suggesting an exon-shuffling mechanism for the generation of an ancestral CERT gene. CERT may have co-evolved with SM to bypass a competing metabolic reaction at the bifurcated point in the anabolism of ceramide. Human CERT is identical to the splicing variant of human Goodpasture antigen-binding protein (GPBP) annotated as an extracellular non-canonical serine/threonine protein kinase. The relationship between CERT and GPBP has also been discussed from an evolutionary aspect. Moreover, using an analogy of "compatible (or osmoprotective) solutes" that can accumulate to very high concentrations in the cytosol without denaturing proteins, choline phospholipids such as PtdCho and SM may act as compatible phospholipids in biomembranes. This article is part of a Special Issue entitled New Frontiers in Sphingolipid Biology.
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Affiliation(s)
- Kentaro Hanada
- Department of Biochemistry and Cell Biology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
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Lauria I, van Üüm J, Mjumjunov-Crncevic E, Walrafen D, Spitta L, Thiele C, Lang T. GLTP mediated non-vesicular GM1 transport between native membranes. PLoS One 2013; 8:e59871. [PMID: 23555818 PMCID: PMC3610762 DOI: 10.1371/journal.pone.0059871] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/19/2013] [Indexed: 11/24/2022] Open
Abstract
Lipid transfer proteins (LTPs) are emerging as key players in lipid homeostasis by mediating non-vesicular transport steps between two membrane surfaces. Little is known about the driving force that governs the direction of transport in cells. Using the soluble LTP glycolipid transfer protein (GLTP), we examined GM1 (monosialotetrahexosyl-ganglioside) transfer to native membrane surfaces. With artificial GM1 donor liposomes, GLTP can be used to increase glycolipid levels over natural levels in either side of the membrane leaflet, i.e., external or cytosolic. In a system with native donor- and acceptor-membranes, we find that GLTP balances highly variable GM1 concentrations in a population of membranes from one cell type, and in addition, transfers lipids between membranes from different cell types. Glycolipid transport is highly efficient, independent of cofactors, solely driven by the chemical potential of GM1 and not discriminating between the extra- and intracellular membrane leaflet. We conclude that GLTP mediated non-vesicular lipid trafficking between native membranes is driven by simple thermodynamic principles and that for intracellular transport less than 1 µM GLTP would be required in the cytosol. Furthermore, the data demonstrates the suitability of GLTP as a tool for artificially increasing glycolipid levels in cellular membranes.
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Affiliation(s)
- Ines Lauria
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - Jan van Üüm
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - Esmina Mjumjunov-Crncevic
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - David Walrafen
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - Luis Spitta
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
| | - Christoph Thiele
- Department of Biochemistry and Cell Biology of Lipids, LIMES Institute, University of Bonn, Bonn, Germany
| | - Thorsten Lang
- Department of Membrane Biochemistry, LIMES (Life and Medical Sciences) Institute, University of Bonn, Bonn, Germany
- * E-mail:
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Zhai X, Momsen WE, Malakhov DA, Boldyrev IA, Momsen MM, Molotkovsky JG, Brockman HL, Brown RE. GLTP-fold interaction with planar phosphatidylcholine surfaces is synergistically stimulated by phosphatidic acid and phosphatidylethanolamine. J Lipid Res 2013; 54:1103-13. [PMID: 23369752 DOI: 10.1194/jlr.m034744] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Among amphitropic proteins, human glycolipid transfer protein (GLTP) forms a structurally-unique fold that translocates on/off membranes to specifically transfer glycolipids. Phosphatidylcholine (PC) bilayers with curvature-induced packing stress stimulate much faster glycolipid intervesicular transfer than nonstressed PC bilayers raising questions about planar cytosol-facing biomembranes being viable sites for GLTP interaction. Herein, GLTP-mediated desorption kinetics of fluorescent glycolipid (tetramethyl-boron dipyrromethene (BODIPY)-label) from lipid monolayers are assessed using a novel microfluidics-based surface balance that monitors lipid lateral packing while simultaneously acquiring surface fluorescence data. At biomembrane-like packing (30-35 mN/m), GLTP uptake of BODIPY-glycolipid from POPC monolayers was nearly nonexistent but could be induced by reducing surface pressure to mirror packing in curvature-stressed bilayers. In contrast, 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE) matrices supported robust BODIPY-glycolipid uptake by GLTP at both high and low surface pressures. Unexpectedly, negatively-charged cytosol-facing lipids, i.e., phosphatidic acid and phosphatidylserine, also supported BODIPY-glycolipid uptake by GLTP at high surface pressure. Remarkably, including both 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphate (5 mol%) and POPE (15 mol%) in POPC synergistically activated GLTP at high surface pressure. Our study shows that matrix lipid headgroup composition, rather than molecular packing per se, is a key regulator of GLTP-fold function while demonstrating the novel capabilities of the microfluidics-based film balance for investigating protein-membrane interfacial interactions.
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Affiliation(s)
- Xiuhong Zhai
- The Hormel Institute, University of Minnesota, Austin, MN, USA
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20
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Hu H, Hao J, Yao H, Chang Q, Li R, Zhang X, Liang Z. Prenatal diagnosis of de novo partial trisomy 18p and partial monosomy 18q recurrent in a family with fatal aortic coarctation. Gene 2012; 517:132-6. [PMID: 23232358 DOI: 10.1016/j.gene.2012.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 11/11/2012] [Accepted: 12/02/2012] [Indexed: 10/27/2022]
Abstract
Aortic coarctation is a life-threatening defect when it occurs with cardiorespiratory failure. Its genetic cause remains unknown. A woman was pregnant twice, both with male fetuses that had partial trisomy 18p, partial monosomy 18q, and aortic coarctation. The syndrome may relate to the aortic coarctation and pulmonary hypoplasia and is life-threatening. ArrayCGH analysis suggested a de novo 17.7 Mb deletion of chromosome 18q21.33→qter (58,413,193 bp to 76,116,029 bp) and a de novo 12.4 Mb duplication of chromosome 18pter→p11.21 (1,543 bp to 12,438,430 bp) at the telomeric end of chromosome 18. To the best of our knowledge, the present chromosomal breakpoint with rearrangement has not been previously described. This chromosome aberration may be responsible for this syndrome.
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Affiliation(s)
- Hua Hu
- Center for Prenatal Diagnosis, The Department of Obstetrics and Gynecology, Southwest Hospital, Third Military Medical University, ChongQing 400038, People's Republic of China
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21
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Mikitova V, Levine TP. Analysis of the key elements of FFAT-like motifs identifies new proteins that potentially bind VAP on the ER, including two AKAPs and FAPP2. PLoS One 2012; 7:e30455. [PMID: 22276202 PMCID: PMC3261905 DOI: 10.1371/journal.pone.0030455] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/20/2011] [Indexed: 12/13/2022] Open
Abstract
Background Two phenylalanines (FF) in an acidic tract (FFAT)-motifs were originally described as having seven elements: an acidic flanking region followed by 6 residues (EFFDA–E). Such motifs are found in several lipid transfer protein (LTP) families, and they interact with a protein on the cytosolic face of the ER called vesicle-associated membrane protein-associated protein (VAP). Mutation of which causes ER stress and motor neuron disease, making it important to determine which proteins bind VAP. Among other proteins that bind VAP, some contain FFAT-like motifs that are missing one or more of the seven elements. Defining how much variation is tolerated in FFAT-like motifs is a preliminary step prior to the identification of the full range of VAP interactors. Results We used a quantifiable in vivo system that measured ER targeting in a reporter yeast strain that over-expressed VAP to study the effect of substituting different elements of FFAT-like motifs in turn. By defining FFAT-like motifs more widely than before, we found them in novel proteins the functions of which had not previously been directly linked to the ER, including: two PKA anchoring proteins, AKAP220 and AKAP110; a family of plant LTPs; and the glycolipid LTP phosphatidylinositol-four-phosphate adaptor-protein-2 (FAPP-2). Conclusion All of the seven essential elements of a FFAT motif tolerate variation, and weak targeting to the ER via VAP is still detected if two elements are substituted. In addition to the strong FFAT motifs already known, there are additional proteins with weaker FFAT-like motifs, which might be functionally important VAP interactors.
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Affiliation(s)
- Veronika Mikitova
- Department of Cell Biology, University College London Institute of Ophthalmology, London, United Kingdom
| | - Timothy P. Levine
- Department of Cell Biology, University College London Institute of Ophthalmology, London, United Kingdom
- * E-mail:
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22
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D'Angelo G, Rega LR, De Matteis MA. Connecting vesicular transport with lipid synthesis: FAPP2. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:1089-95. [PMID: 22266015 PMCID: PMC4331668 DOI: 10.1016/j.bbalip.2012.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 12/29/2011] [Accepted: 01/02/2012] [Indexed: 12/22/2022]
Abstract
Next to the protein-based machineries composed of small G-proteins, coat complexes, SNAREs and tethering factors, the lipid-based machineries are emerging as important players in membrane trafficking. As a component of these machineries, lipid transfer proteins have recently attracted the attention of cell biologists for their involvement in trafficking along different segments of the secretory pathway. Among these, the four-phosphate adaptor protein 2 (FAPP2) was discovered as a protein that localizes dynamically with the trans-Golgi network and regulates the transport of proteins from the Golgi complex to the cell surface. Later studies have highlighted a role for FAPP2 as lipid transfer protein involved in glycosphingolipid metabolism at the Golgi complex. Here we discuss the available evidence on the function of FAPP2 in both membrane trafficking and lipid metabolism and propose a mechanism of action of FAPP2 that integrates its activities in membrane trafficking and in lipid transfer. This article is part of a Special Issue entitled Lipids and Vesicular Transport.
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Human glycolipid transfer protein (GLTP) expression modulates cell shape. PLoS One 2011; 6:e19990. [PMID: 21625605 PMCID: PMC3097243 DOI: 10.1371/journal.pone.0019990] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 04/19/2011] [Indexed: 02/06/2023] Open
Abstract
Glycolipid transfer protein (GLTP) accelerates glycosphingolipid (GSL) intermembrane transfer via a unique lipid transfer/binding fold (GLTP-fold) that defines the GLTP superfamily and is the prototype for GLTP-like domains in larger proteins, i.e. phosphoinositol 4-phosphate adaptor protein-2 (FAPP2). Although GLTP-folds are known to play roles in the nonvesicular intracellular trafficking of glycolipids, their ability to alter cell phenotype remains unexplored. In the present study, overexpression of human glycolipid transfer protein (GLTP) was found to dramatically alter cell phenotype, with cells becoming round between 24 and 48 h after transfection. By 48 h post transfection, ∼70% conversion to the markedly round shape was evident in HeLa and HEK-293 cells, but not in A549 cells. In contrast, overexpression of W96A-GLTP, a liganding-site point mutant with abrogated ability to transfer glycolipid, did not alter cell shape. The round adherent cells exhibited diminished motility in wound healing assays and an inability to endocytose cholera toxin but remained viable and showed little increase in apoptosis as assessed by poly(ADP-ribose) polymerase cleavage. A round cell phenotype also was induced by overexpression of FAPP2, which binds/transfers glycolipid via its C-terminal GLTP-like fold, but not by a plant GLTP ortholog (ACD11), which is incapable of glycolipid binding/transfer. Screening for human protein partners of GLTP by yeast two hybrid screening and by immuno-pulldown analyses revealed regulation of the GLTP-induced cell rounding response by interaction with δ-catenin. Remarkably, while δ-catenin overexpression alone induced dendritic outgrowths, coexpression of GLTP along with δ-catenin accelerated transition to the rounded phenotype. The findings represent the first known phenotypic changes triggered by GLTP overexpression and regulated by direct interaction with a p120-catenin protein family member.
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Tuuf J, Kjellberg MA, Molotkovsky JG, Hanada K, Mattjus P. The intermembrane ceramide transport catalyzed by CERT is sensitive to the lipid environment. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:229-35. [DOI: 10.1016/j.bbamem.2010.09.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 11/26/2022]
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Monitoring glycolipid transfer protein activity and membrane interaction with the surface plasmon resonance technique. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:47-54. [DOI: 10.1016/j.bbamem.2010.08.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 08/17/2010] [Accepted: 08/24/2010] [Indexed: 01/23/2023]
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