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Pathak A, Willis KG, Bankaitis VA, McDermott MI. Mammalian START-like phosphatidylinositol transfer proteins - Physiological perspectives and roles in cancer biology. Biochim Biophys Acta Mol Cell Biol Lipids 2024:159529. [PMID: 38945251 DOI: 10.1016/j.bbalip.2024.159529] [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: 03/29/2024] [Revised: 06/09/2024] [Accepted: 06/25/2024] [Indexed: 07/02/2024]
Abstract
PtdIns and its phosphorylated derivatives, the phosphoinositides, are the biochemical components of a major pathway of intracellular signaling in all eukaryotic cells. These lipids are few in terms of cohort of unique positional isomers, and are quantitatively minor species of the bulk cellular lipidome. Nevertheless, phosphoinositides regulate an impressively diverse set of biological processes. It is from that perspective that perturbations in phosphoinositide-dependent signaling pathways are increasingly being recognized as causal foundations of many human diseases - including cancer. Although phosphatidylinositol transfer proteins (PITPs) are not enzymes, these proteins are physiologically significant regulators of phosphoinositide signaling. As such, PITPs are conserved throughout the eukaryotic kingdom. Their biological importance notwithstanding, PITPs remain understudied. Herein, we review current information regarding PITP biology primarily focusing on how derangements in PITP function disrupt key signaling/developmental pathways and are associated with a growing list of pathologies in mammals.
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Affiliation(s)
- Adrija Pathak
- E.L. Wehner-Welch Laboratory, Department of Cell Biology & Genetics, 116 Reynolds Medical Bldg., Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America
| | - Katelyn G Willis
- E.L. Wehner-Welch Laboratory, Department of Cell Biology & Genetics, 116 Reynolds Medical Bldg., Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America
| | - Vytas A Bankaitis
- E.L. Wehner-Welch Laboratory, Department of Cell Biology & Genetics, 116 Reynolds Medical Bldg., Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America
| | - Mark I McDermott
- E.L. Wehner-Welch Laboratory, Department of Cell Biology & Genetics, 116 Reynolds Medical Bldg., Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America.
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2
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Cockcroft S. The expanding roles of PI4P and PI(4,5)P 2 at the plasma membrane: Role of phosphatidylinositol transfer proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2024; 1869:159394. [PMID: 37714261 DOI: 10.1016/j.bbalip.2023.159394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/31/2023] [Accepted: 09/05/2023] [Indexed: 09/17/2023]
Abstract
Phosphoinositides are phosphorylated derivatives of phosphatidylinositol, a phospholipid that is synthesised at the endoplasmic reticulum. The plasma membrane contains the enzymes to phosphorylate phosphatidylinositol and is therefore rich in the phosphorylated derivatives, PI4P and PI(4,5)P2. PI(4,5)P2 is a substrate for phospholipase C and during cell signaling, PI(4,5)P2 levels are reduced. Here I discuss a family of proteins, phosphatidylinositol transfer proteins (PITPs) that can restore PI(4,5)P2 levels.
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Affiliation(s)
- Shamshad Cockcroft
- Department of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, 21 University Street, London WC1E 6JJ, UK.
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3
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Mallick R, Bhowmik P, Duttaroy AK. Targeting fatty acid uptake and metabolism in cancer cells: A promising strategy for cancer treatment. Biomed Pharmacother 2023; 167:115591. [PMID: 37774669 DOI: 10.1016/j.biopha.2023.115591] [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: 08/24/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023] Open
Abstract
Despite scientific development, cancer is still a fatal disease. The development of cancer is thought to be significantly influenced by fatty acids. Several mechanisms that control fatty acid absorption and metabolism are reported to be altered in cancer cells to support their survival. Cancer cells can use de novo synthesis or uptake of extracellular fatty acid if one method is restricted. This factor makes it more difficult to target one pathway while failing to treat the disease properly. Side effects may also arise if several inhibitors simultaneously target many targets. If a viable inhibitor could work on several routes, the number of negative effects might be reduced. Comparative investigations against cell viability have found several potent natural and manmade substances. In this review, we discuss the complex roles that fatty acids play in the development of tumors and the progression of cancer, newly discovered and potentially effective natural and synthetic compounds that block the uptake and metabolism of fatty acids, the adverse side effects that can occur when multiple inhibitors are used to treat cancer, and emerging therapeutic approaches.
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Affiliation(s)
- Rahul Mallick
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Finland
| | - Prasenjit Bhowmik
- Department of Chemistry, Uppsala Biomedical Centre, Uppsala University, Sweden
| | - Asim K Duttaroy
- Department of Nutrition, Institute of Basic Medical Sciences, Faculty of Medicine, University of Oslo, Norway.
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Zhao L, Thorsheim CL, Suzuki A, Stalker TJ, Min SH, Krishnaswamy S, Cockcroft S, Anderson KE, Weiderhold B, Abrams CS. Individual phosphatidylinositol transfer proteins have distinct functions that do not involve lipid transfer activity. Blood Adv 2023; 7:4233-4246. [PMID: 36930803 PMCID: PMC10424146 DOI: 10.1182/bloodadvances.2022008735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 03/19/2023] Open
Abstract
Platelets use signal transduction pathways facilitated by class I phosphatidylinositol transfer proteins (PITPs). The 2 mammalian class I PITPs, PITPα and PITPβ, are single PITP domain soluble proteins that are encoded by different genes and share 77% sequence identity, although their individual roles in mammalian biology remain uncharacterized. These proteins are believed to shuttle phosphatidylinositol and phosphatidylcholine between separate intracellular membrane compartments, thereby regulating phosphoinositide synthesis and second messenger formation. Previously, we observed that platelet-specific deletion of PITPα, the predominantly expressed murine PITP isoform, had no effect on hemostasis but impaired tumor metastasis formation and disrupted phosphoinositide signaling. Here, we found that mice lacking the less expressed PITPβ in their platelets exhibited a similar phenotype. However, in contrast to PITPα-null platelet lysates, which have impaired lipid transfer activity, PITPβ-null platelet lysates have essentially normal lipid transfer activity, although both isoforms contribute to phosphoinositide synthesis in vitro. Moreover, we found that platelet-specific deletion of both PITPs led to ex vivo platelet aggregation/secretion and spreading defects, impaired tail bleeding, and profound tumor dissemination. Our study also demonstrated that PITP isoforms are required to maintain endogenous phosphoinositide PtdInsP2 levels and agonist-stimulated second messenger formation. The data shown here demonstrate that the 2 isoforms are functionally overlapping and that a single isoform is able to maintain the homeostasis of platelets. However, both class I PITP isoforms contribute to phosphoinositide signaling in platelets through distinct biochemical mechanisms or different subcellular domains.
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Affiliation(s)
- Liang Zhao
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Chelsea L. Thorsheim
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Aae Suzuki
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Timothy J. Stalker
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sang H. Min
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Sriram Krishnaswamy
- Department of Pediatrics, Research Institute, Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA
| | - Shamshad Cockcroft
- Division of Bioscience, University College London, London, United Kingdom
| | - Karen E. Anderson
- Signaling ISP, Babraham Institute, Babraham, Cambridge, United Kingdom
| | - Brittany Weiderhold
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Charles S. Abrams
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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5
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Yuan T, Wang J, Shi C, Wang Y, Xia B, Xu W, Yang H, Yang Y, Ye MT, Khalid S, Liang Y, Tian C, You MJ, Wang Y. Downregulation of FAPP2 gene induces cell autophagy and inhibits PI3K/AKT/mTOR pathway in T-cell acute lymphoblastic leukemia. Hematol Oncol 2021; 40:249-257. [PMID: 34796518 DOI: 10.1002/hon.2948] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 08/16/2021] [Accepted: 11/08/2021] [Indexed: 11/09/2022]
Abstract
T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy. Most patients with T-ALL are treated with high-dose multi-agent chemotherapy due to limited targeted therapeutic options. To further investigate its pathogenesis and establish new therapeutic targets, we studied the role of FAPP2, a Golgi protein, that is, highly expressed in T-ALL, in the growth and function of T-ALL. We found that T-ALL cells underwent reduced cell proliferation and sub-G1 accumulation after knocking down of FAPP2 gene using shRNA systems. Instead, FAPP2 downregulation promoted cell autophagy. The level of autophagy markers, LC3Ⅱ/Ⅰ, Beclin1, and ATG5, was markedly increased, whereas that of P62 decreased after FAPP2 knocking down in T-ALL cells. FAPP2 knocking down led to the accumulation of LC3 in the cytoplasm of T-ALL cells as shown by fluorescence microscopy. In addition, the level of PI(4)P and PI(3,4,5)P decreased and phosphorylation of P-AKT and P-mTOR were downregulated in FAPP2 knock-down cells. In summary, our results show that decreased expression of FAPP2 inhibited cell proliferation, resulted in the sub-G1 phase accumulation of T-ALL cells, and enhanced autophagy of T-ALL cells, likely mediated by PI(4)P, PI(3,4,5)P, and PI3K/AKT/mTOR pathway. Our results provide a new insight into the pathogenesis and development of potential targeted therapy of T-ALL.
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Affiliation(s)
- Tian Yuan
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Jinhuan Wang
- Department of Oncology, Second Hospital of Tianjin Medical University, Institute of Urology, Tianjin, China
| | - Ce Shi
- NHC Key Laboratory of Cell Transplantation, First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Yi Wang
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Bing Xia
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Wen Xu
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Hongliang Yang
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - Yaling Yang
- NHC Key Laboratory of Cell Transplantation, First Affiliated Hospital, Harbin Medical University, Harbin, Heilongjiang Province, China
| | - Matthew T Ye
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Samah Khalid
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yong Liang
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA.,Department of Clinical Medicine, Taizhou University School of Medicine, Taizhou, Zhejiang Province, China
| | - Chen Tian
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
| | - M James You
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Yafei Wang
- Key Laboratory of Cancer Immunology and Biotherapy, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center of Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China
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6
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Lete MG, Tripathi A, Chandran V, Bankaitis VA, McDermott MI. Lipid transfer proteins and instructive regulation of lipid kinase activities: Implications for inositol lipid signaling and disease. Adv Biol Regul 2020; 78:100740. [PMID: 32992233 PMCID: PMC7986245 DOI: 10.1016/j.jbior.2020.100740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 06/16/2020] [Accepted: 06/24/2020] [Indexed: 05/17/2023]
Abstract
Cellular membranes are critical platforms for intracellular signaling that involve complex interfaces between lipids and proteins, and a web of interactions between a multitude of lipid metabolic pathways. Membrane lipids impart structural and functional information in this regulatory circuit that encompass biophysical parameters such as membrane thickness and fluidity, as well as chaperoning the interactions of protein binding partners. Phosphatidylinositol and its phosphorylated derivatives, the phosphoinositides, play key roles in intracellular membrane signaling, and these involvements are translated into an impressively diverse set of biological outcomes. The phosphatidylinositol transfer proteins (PITPs) are key regulators of phosphoinositide signaling. Found in a diverse array of organisms from plants, yeast and apicomplexan parasites to mammals, PITPs were initially proposed to be simple transporters of lipids between intracellular membranes. It now appears increasingly unlikely that the soluble versions of these proteins perform such functions within the cell. Rather, these serve to facilitate the activity of intrinsically biologically insufficient inositol lipid kinases and, in so doing, promote diversification of the biological outcomes of phosphoinositide signaling. The central engine for execution of such functions is the lipid exchange cycle that is a fundamental property of PITPs. How PITPs execute lipid exchange remains very poorly understood. Molecular dynamics simulation approaches are now providing the first atomistic insights into how PITPs, and potentially other lipid-exchange/transfer proteins, operate.
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Affiliation(s)
- Marta G Lete
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Institute Biofisika (UPV/EHU, CSIC) and University of the Basque Country, Leioa, Spain
| | - Ashutosh Tripathi
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vijay Chandran
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA
| | - Vytas A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA; Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, 77843-2128, USA; Department of Chemistry, Texas A&M University, College Station, TX, 77840, USA
| | - Mark I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Sciences Center, College Station, TX, 77843-1114, USA.
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7
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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: 25] [Impact Index Per Article: 6.3] [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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8
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Koundouros N, Poulogiannis G. Reprogramming of fatty acid metabolism in cancer. Br J Cancer 2020; 122:4-22. [PMID: 31819192 PMCID: PMC6964678 DOI: 10.1038/s41416-019-0650-z] [Citation(s) in RCA: 740] [Impact Index Per Article: 185.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/21/2019] [Accepted: 11/01/2019] [Indexed: 02/08/2023] Open
Abstract
A common feature of cancer cells is their ability to rewire their metabolism to sustain the production of ATP and macromolecules needed for cell growth, division and survival. In particular, the importance of altered fatty acid metabolism in cancer has received renewed interest as, aside their principal role as structural components of the membrane matrix, they are important secondary messengers, and can also serve as fuel sources for energy production. In this review, we will examine the mechanisms through which cancer cells rewire their fatty acid metabolism with a focus on four main areas of research. (1) The role of de novo synthesis and exogenous uptake in the cellular pool of fatty acids. (2) The mechanisms through which molecular heterogeneity and oncogenic signal transduction pathways, such as PI3K-AKT-mTOR signalling, regulate fatty acid metabolism. (3) The role of fatty acids as essential mediators of cancer progression and metastasis, through remodelling of the tumour microenvironment. (4) Therapeutic strategies and considerations for successfully targeting fatty acid metabolism in cancer. Further research focusing on the complex interplay between oncogenic signalling and dysregulated fatty acid metabolism holds great promise to uncover novel metabolic vulnerabilities and improve the efficacy of targeted therapies.
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Affiliation(s)
- Nikos Koundouros
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK
| | - George Poulogiannis
- Signalling and Cancer Metabolism Team, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London, SW3 6JB, UK.
- Division of Computational and Systems Medicine, Department of Surgery and Cancer, Imperial College London, London, SW7 2AZ, UK.
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9
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Nishimura T, Stefan CJ. Specialized ER membrane domains for lipid metabolism and transport. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1865:158492. [PMID: 31349025 DOI: 10.1016/j.bbalip.2019.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 07/02/2019] [Accepted: 07/03/2019] [Indexed: 11/15/2022]
Abstract
The endoplasmic reticulum (ER) is a highly organized organelle that performs vital functions including de novo membrane lipid synthesis and transport. Accordingly, numerous lipid biosynthesis enzymes are localized in the ER membrane. However, it is now evident that lipid metabolism is sub-compartmentalized within the ER and that lipid biosynthetic enzymes engage with lipid transfer proteins (LTPs) to rapidly shuttle newly synthesized lipids from the ER to other organelles. As such, intimate relationships between lipid metabolism and lipid transfer pathways exist within the ER network. Notably, certain LTPs enhance the activities of lipid metabolizing enzymes; likewise, lipid metabolism can ensure the specificity of LTP transfer/exchange reactions. Yet, our understanding of these mutual relationships is still emerging. Here, we highlight past and recent key findings on specialized ER membrane domains involved in efficient lipid metabolism and transport and consider unresolved issues in the field.
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Affiliation(s)
- Taki Nishimura
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
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10
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Gong B, Li Z, Xiao W, Li G, Ding S, Meng A, Jia S. Sec14l3 potentiates VEGFR2 signaling to regulate zebrafish vasculogenesis. Nat Commun 2019; 10:1606. [PMID: 30962435 PMCID: PMC6453981 DOI: 10.1038/s41467-019-09604-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
Vascular endothelial growth factor (VEGF) regulates vasculogenesis by using its tyrosine kinase receptors. However, little is known about whether Sec14-like phosphatidylinositol transfer proteins (PTP) are involved in this process. Here, we show that zebrafish sec14l3, one of the family members, specifically participates in artery and vein formation via regulating angioblasts and subsequent venous progenitors’ migration during vasculogenesis. Vascular defects caused by sec14l3 depletion are partially rescued by restoration of VEGFR2 signaling at the receptor or downstream effector level. Biochemical analyses show that Sec14l3/SEC14L2 physically bind to VEGFR2 and prevent it from dephosphorylation specifically at the Y1175 site by peri-membrane tyrosine phosphatase PTP1B, therefore potentiating VEGFR2 signaling activation. Meanwhile, Sec14l3 and SEC14L2 interact with RAB5A/4A and facilitate the formation of their GTP-bound states, which might be critical for VEGFR2 endocytic trafficking. Thus, we conclude that Sec14l3 controls vasculogenesis in zebrafish via the regulation of VEGFR2 activation. The growth factor VEGF is known to regulate vasculogenesis but the downstream pathways activated are unclear. Here, the authors report that Sec14l3, a member of the PITP (phosphatidyl inositol transfer proteins) family regulates the formation of zebrafish vasculature by promoting VEGFR2 endocytic trafficking.
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Affiliation(s)
- Bo Gong
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Zhihao Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Wanghua Xiao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Guangyuan Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Shihui Ding
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China
| | - Anming Meng
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China.
| | - Shunji Jia
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, 100084, Beijing, China.
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11
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Grabon A, Bankaitis VA, McDermott MI. The interface between phosphatidylinositol transfer protein function and phosphoinositide signaling in higher eukaryotes. J Lipid Res 2018; 60:242-268. [PMID: 30504233 DOI: 10.1194/jlr.r089730] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/12/2018] [Indexed: 12/22/2022] Open
Abstract
Phosphoinositides are key regulators of a large number of diverse cellular processes that include membrane trafficking, plasma membrane receptor signaling, cell proliferation, and transcription. How a small number of chemically distinct phosphoinositide signals are functionally amplified to exert specific control over such a diverse set of biological outcomes remains incompletely understood. To this end, a novel mechanism is now taking shape, and it involves phosphatidylinositol (PtdIns) transfer proteins (PITPs). The concept that PITPs exert instructive regulation of PtdIns 4-OH kinase activities and thereby channel phosphoinositide production to specific biological outcomes, identifies PITPs as central factors in the diversification of phosphoinositide signaling. There are two evolutionarily distinct families of PITPs: the Sec14-like and the StAR-related lipid transfer domain (START)-like families. Of these two families, the START-like PITPs are the least understood. Herein, we review recent insights into the biochemical, cellular, and physiological function of both PITP families with greater emphasis on the START-like PITPs, and we discuss the underlying mechanisms through which these proteins regulate phosphoinositide signaling and how these actions translate to human health and disease.
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Affiliation(s)
- Aby Grabon
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Vytas A Bankaitis
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
| | - Mark I McDermott
- E. L. Wehner-Welch Laboratory, Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114
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12
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Causey DR, Pohl MAN, Stead DA, Martin SAM, Secombes CJ, Macqueen DJ. High-throughput proteomic profiling of the fish liver following bacterial infection. BMC Genomics 2018; 19:719. [PMID: 30285610 PMCID: PMC6167799 DOI: 10.1186/s12864-018-5092-0] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/19/2018] [Indexed: 02/07/2023] Open
Abstract
Background High-throughput proteomics was used to determine the role of the fish liver in defense responses to bacterial infection. This was done using a rainbow trout (Oncorhynchus mykiss) model following infection with Aeromonas salmonicida, the causative agent of furunculosis. The vertebrate liver has multifaceted functions in innate immunity, metabolism, and growth; we hypothesize this tissue serves a dual role in supporting host defense in parallel to metabolic adjustments that promote effective immune function. While past studies have reported mRNA responses to A. salmonicida in salmonids, the impact of bacterial infection on the liver proteome remains uncharacterized in fish. Results Rainbow trout were injected with A. salmonicida or PBS (control) and liver extracted 48 h later for analysis on a hybrid quadrupole-Orbitrap mass spectrometer. A label-free method was used for protein abundance profiling, which revealed a strong innate immune response along with evidence to support parallel rewiring of metabolic and growth systems. 3076 proteins were initially identified against all proteins (n = 71,293 RefSeq proteins) annotated in a single high-quality rainbow trout reference genome, of which 2433 were maintained for analysis post-quality filtering. Among the 2433 proteins, 109 showed significant differential abundance following A. salmonicida challenge, including many upregulated complement system and acute phase response proteins, in addition to molecules with putative functions that may support metabolic re-adjustments. We also identified novel expansions in the complement system due to gene and whole genome duplication events in salmonid evolutionary history, including eight C3 proteins showing differential changes in abundance. Conclusions This study provides the first high-throughput proteomic examination of the fish liver in response to bacterial challenge, revealing novel markers for the host defense response, and evidence of metabolic remodeling in conjunction with activation of innate immunity. Electronic supplementary material The online version of this article (10.1186/s12864-018-5092-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dwight R Causey
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Moritz A N Pohl
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - David A Stead
- Aberdeen Proteomics, University of Aberdeen, The Rowett Institute, Aberdeen, UK
| | | | | | - Daniel J Macqueen
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK.
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Phospholipid transport protein function at organelle contact sites. Curr Opin Cell Biol 2018; 53:52-60. [PMID: 29859321 PMCID: PMC6141807 DOI: 10.1016/j.ceb.2018.04.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/12/2018] [Accepted: 04/29/2018] [Indexed: 11/21/2022]
Abstract
Phospholipids are synthesized at the endoplasmic reticulum (ER), the largest membrane bound organelle that forms membrane contact sites (MCS) with almost every other organelle. MCS are locations at which the membrane es of two organelles are closely positioned to provide a microenvironment where proteins in one membrane can interact with the opposite membrane. Thus, MCS provide an ideal location at which lipid transfer proteins (LTPs) can achieve the efficient transfer of individual classes of lipids from the ER to other organelles via non-vesicular transport. Here we provide an overview of emerging findings on the localization and biochemical activity of LTPs at MCS between the ER and other cellular membranes. The localization of LTPs at MCS offers an elegant cell biological solution to tune local lipid composition to ongoing cell physiology.
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Topological organisation of the phosphatidylinositol 4,5-bisphosphate-phospholipase C resynthesis cycle: PITPs bridge the ER-PM gap. Biochem J 2017; 473:4289-4310. [PMID: 27888240 DOI: 10.1042/bcj20160514c] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 09/08/2016] [Accepted: 09/12/2016] [Indexed: 12/13/2022]
Abstract
Phospholipase C (PLC) is a receptor-regulated enzyme that hydrolyses phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) at the plasma membrane (PM) triggering three biochemical consequences, the generation of soluble inositol 1,4,5-trisphosphate (IP3), membrane-associated diacylglycerol (DG) and the consumption of PM PI(4,5)P2 Each of these three signals triggers multiple molecular processes impacting key cellular properties. The activation of PLC also triggers a sequence of biochemical reactions, collectively referred to as the PI(4,5)P2 cycle that culminates in the resynthesis of this lipid. The biochemical intermediates of this cycle and the enzymes that mediate these reactions are topologically distributed across two membrane compartments, the PM and the endoplasmic reticulum (ER). At the PM, the DG formed during PLC activation is rapidly converted into phosphatidic acid (PA) that needs to be transported to the ER where the machinery for its conversion into PI is localised. Conversely, PI from the ER needs to be rapidly transferred to the PM where it can be phosphorylated by lipid kinases to regenerate PI(4,5)P2 Thus, two lipid transport steps between membrane compartments through the cytosol are required for the replenishment of PI(4,5)P2 at the PM. Here, we review the topological constraints in the PI(4,5)P2 cycle and current understanding how these constraints are overcome during PLC signalling. In particular, we discuss the role of lipid transfer proteins in this process. Recent findings on the biochemical properties of a membrane-associated lipid transfer protein of the PITP family, PITPNM proteins (alternative name RdgBα/Nir proteins) that localise to membrane contact sites are discussed. Studies in both Drosophila and mammalian cells converge to provide a resolution to the conundrum of reciprocal transfer of PA and PI during PLC signalling.
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Gong B, Shen W, Xiao W, Meng Y, Meng A, Jia S. The Sec14-like phosphatidylinositol transfer proteins Sec14l3/SEC14L2 act as GTPase proteins to mediate Wnt/Ca 2+ signaling. eLife 2017; 6. [PMID: 28463110 PMCID: PMC5423769 DOI: 10.7554/elife.26362] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 04/30/2017] [Indexed: 12/24/2022] Open
Abstract
The non-canonical Wnt/Ca2+ signaling pathway plays important roles in embryonic development, tissue formation and diseases. However, it is unclear how the Wnt ligand-stimulated, G protein-coupled receptor Frizzled activates phospholipases for calcium release. Here, we report that the zebrafish/human phosphatidylinositol transfer protein Sec14l3/SEC14L2 act as GTPase proteins to transduce Wnt signals from Frizzled to phospholipase C (PLC). Depletion of sec14l3 attenuates Wnt/Ca2+ responsive activity and causes convergent and extension (CE) defects in zebrafish embryos. Biochemical analyses in mammalian cells indicate that Sec14l3-GDP forms complex with Frizzled and Dishevelled; Wnt ligand binding of Frizzled induces translocation of Sec14l3 to the plasma membrane; and then Sec14l3-GTP binds to and activates phospholipase Cδ4a (Plcδ4a); subsequently, Plcδ4a initiates phosphatidylinositol-4,5-bisphosphate (PIP2) signaling, ultimately stimulating calcium release. Furthermore, Plcδ4a can act as a GTPase-activating protein to accelerate the hydrolysis of Sec14l3-bound GTP to GDP. Our data provide a new insight into GTPase protein-coupled Wnt/Ca2+ signaling transduction.
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Affiliation(s)
- Bo Gong
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Weimin Shen
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Wanghua Xiao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yaping Meng
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Anming Meng
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
| | - Shunji Jia
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, China
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The role of phosphatidylinositol-transfer proteins at membrane contact sites. Biochem Soc Trans 2016; 44:419-24. [PMID: 27068949 DOI: 10.1042/bst20150182] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Indexed: 12/24/2022]
Abstract
Phosphatidylinositol-transfer proteins (PITPs) have been initially identified as soluble factors that accelerate the monomeric exchange of either phosphatidylinositol (PI) or phosphatidylcholine (PC) between membrane bilayersin vitro They are highly conserved in eukaryotes and have been implicated in different cellular processes, including vesicular trafficking, signal transduction, and lipid metabolism. Recent studies suggest that PITPs function at membrane contact sites (MCSs) to facilitate the transport of PI from its synthesis site at the endoplasmic reticulum (ER) to various membrane compartments. In this review, we describe the underlying mechanism of PITPs targeting to MCSs, discuss their cellular roles and potential mode of action.
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Phosphatidylinositol and phosphatidic acid transport between the ER and plasma membrane during PLC activation requires the Nir2 protein. Biochem Soc Trans 2016; 44:197-201. [PMID: 26862206 DOI: 10.1042/bst20150187] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phospholipase C (PLC)-mediated hydrolysis of the limited pool of plasma membrane (PM) phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] requires replenishment from a larger pool of phosphatidylinositol (PtdIns) via sequential phosphorylation by PtdIns 4-kinases and phosphatidylinositol 4-phosphate (PtdIns4P) 5-kinases. Since PtdIns is synthesized in the endoplasmic reticulum (ER) and PtdIns(4,5)P2 is generated in the PM, it has been postulated that PtdIns transfer proteins (PITPs) provide the means for this lipid transfer function. Recent studies identified the large PITP protein, Nir2 as important for PtdIns transfer from the ER to the PM. It was also found that Nir2 was required for the transfer of phosphatidic acid (PtdOH) from the PM to the ER. In Nir2-depleted cells, activation of PLC leads to PtdOH accumulation in the PM and PtdIns synthesis becomes severely impaired. In quiescent cells, Nir2 is localized to the ER via interaction of its FFAT domain with ER-bound VAMP-associated proteins VAP-A and-B. After PLC activation, Nir2 also binds to the PM via interaction of its C-terminal domains with diacylglycerol (DAG) and PtdOH. Through these interactions, Nir2 functions in ER-PM contact zones. Mutations in VAP-B that have been identified in familial forms of amyotrophic lateral sclerosis (ALS or Lou-Gehrig's disease) cause aggregation of the VAP-B protein, which then impairs its binding to several proteins, including Nir2. These findings have shed new lights on the importance of non-vesicular lipid transfer of PtdIns and PtdOH in ER-PM contact zones with a possible link to a devastating human disease.
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18
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Lipid transfer proteins and the tuning of compartmental identity in the Golgi apparatus. Chem Phys Lipids 2016; 200:42-61. [DOI: 10.1016/j.chemphyslip.2016.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
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Chang CL, Liou J. Homeostatic regulation of the PI(4,5)P2-Ca(2+) signaling system at ER-PM junctions. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1861:862-873. [PMID: 26924250 DOI: 10.1016/j.bbalip.2016.02.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/17/2016] [Accepted: 02/19/2016] [Indexed: 10/22/2022]
Abstract
The phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2)-Ca(2+) signaling system is important for cell activation in response to various extracellular stimuli. This signaling system is initiated by receptor-induced hydrolysis of PI(4,5)P2 in the plasma membrane (PM) to generate the soluble second messenger inositol 1,4,5-trisphosphate (IP3). IP3 subsequently triggers the release of Ca(2+) from the endoplasmic reticulum (ER) store to the cytosol to activate Ca(2+)-mediated responses, such as secretion and proliferation. The consumed PM PI(4,5)P2 and ER Ca(2+) must be quickly restored to sustain signaling responses, and to maintain the homeostasis of PI(4,5)P2 and Ca(2+). Since phosphatidylinositol (PI), the precursor lipid for PM PI(4,5)P2, is synthesized in the ER membrane, and a Ca(2+) influx across the PM is required to refill the ER Ca(2+) store, efficient communications between the ER and the PM are critical for the homeostatic regulation of the PI(4,5)P2-Ca(2+) signaling system. This review describes the major findings that established the framework of the PI(4,5)P2-Ca(2+) signaling system, and recent discoveries on feedback control mechanisms at ER-PM junctions that sustain the PI(4,5)P2-Ca(2+) signaling system. Particular emphasis is placed on the characterization of ER-PM junctions where efficient communications between the ER and the PM occur, and the activation mechanisms of proteins that dynamically localize to ER-PM junctions to provide the feedback control during PI(4,5)P2-Ca(2+) signaling, including the ER Ca(2+) sensor STIM1, the extended synaptotagmin E-Syt1, and the PI transfer protein Nir2. 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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Affiliation(s)
- Chi-Lun Chang
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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20
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RdgBα reciprocally transfers PA and PI at ER–PM contact sites to maintain PI(4,5)P2 homoeostasis during phospholipase C signalling in Drosophila photoreceptors. Biochem Soc Trans 2016; 44:286-92. [DOI: 10.1042/bst20150228] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Phosphatidylinositol (PI) is the precursor lipid for the synthesis of PI 4,5-bisphosphate [PI(4,5)P2] at the plasma membrane (PM) and is sequentially phosphorylated by the lipid kinases, PI 4-kinase and phosphatidylinositol 4-phosphate (PI4P)-5-kinase. Receptor-mediated hydrolysis of PI(4,5)P2 takes place at the PM but PI resynthesis occurs at the endoplasmic reticulum (ER). Thus PI(4,5)P2 resynthesis requires the reciprocal transport of two key intermediates, phosphatidic acid (PA) and PI between the ER and the PM. PI transfer proteins (PITPs), defined by the presence of the PITP domain, can facilitate lipid transfer between membranes; the PITP domain comprises a hydrophobic cavity with dual specificity but accommodates a single phospholipid molecule. The class II PITP, retinal degeneration type B (RdgB)α is a multi-domain protein and its PITP domain can bind and transfer PI and PA. In Drosophila photoreceptors, a well-defined G-protein-coupled phospholipase Cβ (PLCβ) signalling pathway, phototransduction defects resulting from loss of RdgBα can be rescued by expression of the PITP domain provided it is competent for both PI and PA transfer. We propose that RdgBα proteins maintain PI(4,5)P2 homoeostasis after PLC activation by facilitating the reciprocal transport of PA and PI at ER–PM membrane contact sites.
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21
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Yadav S, Garner K, Georgiev P, Li M, Gomez-Espinosa E, Panda A, Mathre S, Okkenhaug H, Cockcroft S, Raghu P. RDGBα, a PtdIns-PtdOH transfer protein, regulates G-protein-coupled PtdIns(4,5)P2 signalling during Drosophila phototransduction. J Cell Sci 2015. [PMID: 26203165 PMCID: PMC4582195 DOI: 10.1242/jcs.173476] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Many membrane receptors activate phospholipase C (PLC) during signalling, triggering changes in the levels of several plasma membrane lipids including phosphatidylinositol (PtdIns), phosphatidic acid (PtdOH) and phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. It is widely believed that exchange of lipids between the plasma membrane and endoplasmic reticulum (ER) is required to restore lipid homeostasis during PLC signalling, yet the mechanism remains unresolved. RDGBα (hereafter RDGB) is a multi-domain protein with a PtdIns transfer protein (PITP) domain (RDGB-PITPd). We find that, in vitro, the RDGB-PITPd binds and transfers both PtdOH and PtdIns. In Drosophila photoreceptors, which experience high rates of PLC activity, RDGB function is essential for phototransduction. We show that binding of PtdIns to RDGB-PITPd is essential for normal phototransduction; however, this property is insufficient to explain the in vivo function because another Drosophila PITP (encoded by vib) that also binds PtdIns cannot rescue the phenotypes of RDGB deletion. In RDGB mutants, PtdIns(4,5)P2 resynthesis at the plasma membrane following PLC activation is delayed and PtdOH levels elevate. Thus RDGB couples the turnover of both PtdIns and PtdOH, key lipid intermediates during G-protein-coupled PtdIns(4,5)P2 turnover.
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Affiliation(s)
- Shweta Yadav
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India
| | - Kathryn Garner
- Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6JJ, UK
| | - Plamen Georgiev
- Inositide Laboratory, Babraham Institute, Cambridge CB22 3AT, UK
| | - Michelle Li
- Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6JJ, UK
| | - Evelyn Gomez-Espinosa
- Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6JJ, UK
| | - Aniruddha Panda
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India Manipal University, Madhav Nagar, Manipal, Karnataka 576104, India
| | - Swarna Mathre
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India Manipal University, Madhav Nagar, Manipal, Karnataka 576104, India
| | | | - Shamshad Cockcroft
- Department of Neuroscience, Physiology and Pharmacology, University College, London WC1E 6JJ, UK
| | - Padinjat Raghu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore, Karnataka 560065, India Inositide Laboratory, Babraham Institute, Cambridge CB22 3AT, UK
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Grabon A, Khan D, Bankaitis VA. Phosphatidylinositol transfer proteins and instructive regulation of lipid kinase biology. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:724-35. [PMID: 25592381 PMCID: PMC5221696 DOI: 10.1016/j.bbalip.2014.12.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 11/21/2014] [Accepted: 12/16/2014] [Indexed: 11/25/2022]
Abstract
Phosphatidylinositol is a metabolic precursor of phosphoinositides and soluble inositol phosphates. Both sets of molecules represent versatile intracellular chemical signals in eukaryotes. While much effort has been invested in understanding the enzymes that produce and consume these molecules, central aspects for how phosphoinositide production is controlled and functionally partitioned remain unresolved and largely unappreciated. It is in this regard that phosphatidylinositol (PtdIns) transfer proteins (PITPs) are emerging as central regulators of the functional channeling of phosphoinositide pools produced on demand for specific signaling purposes. The physiological significance of these proteins is amply demonstrated by the consequences that accompany deficits in individual PITPs. Although the biological problem is fascinating, and of direct relevance to disease, PITPs remain largely uncharacterized. Herein, we discuss our perspectives regarding what is known about how PITPs work as molecules, and highlight progress in our understanding of how PITPs are integrated into cellular physiology. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Aby Grabon
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA
| | - Danish Khan
- Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA
| | - Vytas A Bankaitis
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, USA; Department of Biochemistry & Biophysics, Texas A&M University, College Station, TX 77843-2128, USA.
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Plant phosphoinositides-complex networks controlling growth and adaptation. Biochim Biophys Acta Mol Cell Biol Lipids 2014; 1851:759-69. [PMID: 25280638 DOI: 10.1016/j.bbalip.2014.09.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/22/2014] [Accepted: 09/23/2014] [Indexed: 11/24/2022]
Abstract
Plants differ in many ways from mammals or yeast. However, plants employ phosphoinositides for the regulation of essential cellular functions as do all other eukaryotes. In recent years the plant phosphoinositide system has been linked to the control of cell polarity. Phosphoinositides are also implicated in plant adaptive responses to changing environmental conditions. The current understanding is that plant phosphoinositides control membrane trafficking, ion channels and the cytoskeleton in similar ways as in other eukaryotic systems, but adapted to meet plant cellular requirements and with some plant-specific features. In addition, the formation of soluble inositol polyphosphates from phosphoinositides is important for the perception of important phytohormones, as the relevant receptor proteins contain such molecules as structural cofactors. Overall, the essential nature of phosphoinositides in plants has been established. Still, the complexity of the phosphoinositide networks in plant cells is only emerging and invites further study of its molecular details. This article is part of a special issue entitled Phosphoinositides.
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Ellina MI, Bouris P, Aletras AJ, Theocharis AD, Kletsas D, Karamanos NK. EGFR and HER2 exert distinct roles on colon cancer cell functional properties and expression of matrix macromolecules. Biochim Biophys Acta Gen Subj 2014; 1840:2651-61. [DOI: 10.1016/j.bbagen.2014.04.019] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/24/2014] [Accepted: 04/25/2014] [Indexed: 01/08/2023]
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Tetraspanin-enriched microdomains and hepatocellular carcinoma progression. Cancer Lett 2014; 351:23-9. [PMID: 24858024 DOI: 10.1016/j.canlet.2014.05.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/05/2014] [Accepted: 05/06/2014] [Indexed: 02/06/2023]
Abstract
As in many tumors, heterogeneity within the cell population is one of the main features of hepatocellular carcinoma (HCC). Heterogeneity results from the ability of tumor to produce multiple subpopulations of cells with diverse genetic, biochemical and immunological characteristics. Little is known about how heterogeneity emerges and how it is maintained. Fluctuations in single cells can be masked or completely misrepresented when cell populations are analyzed. It has become exceedingly apparent that the utility of measurement based on the analysis of bulk specimens is limited by intra-tumor genetic and epigenetic heterogeneity, as characteristics of the most abundant cell type might not necessarily predict the properties of cell populations. Yet, such non-uniformities often unveil molecular patterns that can represent mechanisms of tumor progression. Interestingly, variability among single cells in a population may arise from different responses to intrinsic and extrinsic perturbations mainly mediated by the plasma membrane. The association of certain proteins, including tetraspanins, and lipids in specific location on the plasma membrane constitutes specialized structure called tetraspanin-enriched microdomains (TEMs). TEMs organization in cancer may reveal essential clues for understanding pathogenic mechanisms underlying cancer progression. Along these lines, TEMs and HCC progression represent a valuable paradigm for gaining a deeper understanding of such mechanisms.
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Heilmann M, Heilmann I. Arranged marriage in lipid signalling? The limited choices of PtdIns(4,5)P2 in finding the right partner. PLANT BIOLOGY (STUTTGART, GERMANY) 2013; 15:789-797. [PMID: 23627419 DOI: 10.1111/plb.12025] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/07/2013] [Indexed: 06/02/2023]
Abstract
Inositol-containing phospholipids (phosphoinositides, PIs) control numerous cellular processes in eukaryotic cells. For plants, a key involvement of PIs has been demonstrated in the regulation of membrane trafficking, cytoskeletal dynamics and in processes mediating the adaptation to changing environmental conditions. Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) mediates its cellular functions via binding to various alternative target proteins. Such downstream targets of PtdIns(4,5)P(2) are characterised by the possession of specific lipid-binding domains, and binding of the PtdIns(4,5)P(2) ligand exerts effects on their activity or localisation. The large number of potential alternative binding partners - and associated cellular processes - raises the question how alternative or even contrapuntal effects of PtdIns(4,5)P(2) are orchestrated to enable cellular function. This article aims to provide an overview of recent insights and new views on how distinct functional pools of PtdIns(4,5)P(2) are generated and maintained. The emerging picture suggests that PtdIns(4,5)P(2) species containing different fatty acids influence the lateral mobility of the lipids in the membrane, possibly enabling specific interactions of PtdIns(4,5)P(2) pools with certain downstream targets. PtdIns(4,5)P(2) pools with certain functions might also be defined by protein-protein interactions of PI4P 5-kinases, which pass PtdIns(4,5)P(2) only to certain downstream partners. Individually or in combination, PtdIns(4,5)P(2) species and specific protein-protein interactions of PI4P 5-kinases might contribute to the channelling of PtdIns(4,5)P(2) signals towards specific functional effects. The dynamic nature of PI-dependent signalling complexes with specific functions is an added challenge for future studies of plant PI signalling.
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Affiliation(s)
- M Heilmann
- Department of Cellular Biochemistry, Institute for Biochemistry and Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany.
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Cockcroft S, Garner K. Potential role for phosphatidylinositol transfer protein (PITP) family in lipid transfer during phospholipase C signalling. Adv Biol Regul 2013; 53:280-291. [PMID: 23916246 DOI: 10.1016/j.jbior.2013.07.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 07/11/2013] [Accepted: 07/12/2013] [Indexed: 06/02/2023]
Abstract
The hallmark of mammalian phosphatidylinositol transfer proteins (PITPs) is to transfer phosphatidylinositol between membrane compartments. In the mammalian genome, there are three genes that code for soluble PITP proteins, PITPα, PITPβ and RdgBβ and two genes that code for membrane-associated multi-domain proteins (RdgBαI and II) containing a PITP domain. PITPα and PITPβ constitute Class I PITPs whilst the RdgB proteins constitute Class II proteins based on sequence analysis. The PITP domain of both Class I and II can sequester one molecule of phosphatidylinositol (PI) in its hydrophobic cavity. Therefore, in principle, PITPs are therefore ideally poised to couple phosphatidylinositol delivery to the PI kinases for substrate provision for phospholipases C during cell activation. Since phosphatidylinositol (4,5)bisphosphate plays critical roles in cells, particularly at the plasma membrane, where it is a substrate for both phospholipase C and phosphoinositide-3-kinases as well as required as an intact lipid to regulate ion channels and the actin cytoskeleton, homeostatic mechanisms to maintain phosphatidylinositol(4,5)bisphosphate levels are vital. To maintain phosphatidylinositol levels, phospholipase C activation inevitably leads to the resynthesis of PI at the endoplasmic reticulum where the enzymes are located. Phosphatidic acid generated at the plasma membrane during phospholipase C activation needs to move to the ER for conversion to PI and here we provide evidence that Class II PITPs are also able to bind and transport phosphatidic acid. Thus RdgB proteins could couple PA and PI transport bidirectionally during phospholipase C signalling.
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Affiliation(s)
- Shamshad Cockcroft
- Dept. of Neuroscience, Physiology and Pharmacology, Division of Biosciences, University College London, London WC1E 6JJ, UK.
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Abstract
Phosphoinositides (PIs) make up only a small fraction of cellular phospholipids, yet they control almost all aspects of a cell's life and death. These lipids gained tremendous research interest as plasma membrane signaling molecules when discovered in the 1970s and 1980s. Research in the last 15 years has added a wide range of biological processes regulated by PIs, turning these lipids into one of the most universal signaling entities in eukaryotic cells. PIs control organelle biology by regulating vesicular trafficking, but they also modulate lipid distribution and metabolism via their close relationship with lipid transfer proteins. PIs regulate ion channels, pumps, and transporters and control both endocytic and exocytic processes. The nuclear phosphoinositides have grown from being an epiphenomenon to a research area of its own. As expected from such pleiotropic regulators, derangements of phosphoinositide metabolism are responsible for a number of human diseases ranging from rare genetic disorders to the most common ones such as cancer, obesity, and diabetes. Moreover, it is increasingly evident that a number of infectious agents hijack the PI regulatory systems of host cells for their intracellular movements, replication, and assembly. As a result, PI converting enzymes began to be noticed by pharmaceutical companies as potential therapeutic targets. This review is an attempt to give an overview of this enormous research field focusing on major developments in diverse areas of basic science linked to cellular physiology and disease.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA.
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Clayton EL, Minogue S, Waugh MG. Mammalian phosphatidylinositol 4-kinases as modulators of membrane trafficking and lipid signaling networks. Prog Lipid Res 2013; 52:294-304. [PMID: 23608234 PMCID: PMC3989048 DOI: 10.1016/j.plipres.2013.04.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Accepted: 04/08/2013] [Indexed: 12/19/2022]
Abstract
The four mammalian phosphatidylinositol 4-kinases modulate inter-organelle lipid trafficking, phosphoinositide signalling and intracellular vesicle trafficking. In addition to catalytic domains required for the synthesis of PI4P, the phosphatidylinositol 4-kinases also contain isoform-specific structural motifs that mediate interactions with proteins such as AP-3 and the E3 ubiquitin ligase Itch, and such structural differences determine isoform-specific roles in membrane trafficking. Moreover, different permutations of phosphatidylinositol 4-kinase isozymes may be required for a single cellular function such as occurs during distinct stages of GPCR signalling and in Golgi to lysosome trafficking. Phosphatidylinositol 4-kinases have recently been implicated in human disease. Emerging paradigms include increased phosphatidylinositol 4-kinase expression in some cancers, impaired functioning associated with neurological pathologies, the subversion of PI4P trafficking functions in bacterial infection and the activation of lipid kinase activity in viral disease. We discuss how the diverse and sometimes overlapping functions of the phosphatidylinositol 4-kinases present challenges for the design of isoform-specific inhibitors in a therapeutic context.
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Affiliation(s)
- Emma L Clayton
- UCL Institute for Liver & Digestive Health, UCL Royal Free Campus, Rowland Hill Street, London NW3 2PF, United Kingdom
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Skippen A, Swigart P, Cockcroft S. Measurement of phospholipase C by monitoring inositol phosphates using [³H]inositol labeling protocols in permeabilized cells. Methods Mol Biol 2013; 937:163-174. [PMID: 23007585 DOI: 10.1007/978-1-62703-086-1_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Data on the production of inositol phosphates is a useful complement to measurements of intracellular Ca(2+). The basic principle is labeling of the inositol lipids by growing the appropriate cell line in culture in the presence of [3H]inositol for 2-3 days to reach labeling equilibrium. Lithium ions at 10 mM inhibits the degradation of inositol phosphates to free inositol and is used to trap the inositol in the inositol polyphosphate forms. Inositol phosphates can be separated with ease from free inositol by using anion exchange chromatography. A method capable of easily processing approximately 40-60 samples in a single day is presented.
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Affiliation(s)
- Alison Skippen
- Department of Neuroscience, Physiology, and Pharmacology, University College London, London, UK
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Abstract
The transport of lipids from their synthesis site at the endoplasmic reticulum (ER) to different target membranes could be mediated by both vesicular and nonvesicular transport mechanisms. Nonvesicular lipid transport appears to be the major transport route of certain lipid species, and could be mediated by either spontaneous lipid transport or by lipid-transfer proteins (LTPs). Although nonvesicular lipid transport has been extensively studied for more than four decades, its underlying mechanism, advantage and regulation, have not been fully explored. In particular, the function of LTPs and their involvement in intracellular lipid movement remain largely controversial. In this article, we describe the pathways by which lipids are synthesized at the ER and delivered to different cellular membranes, and discuss the role of LTPs in lipid transport both in vitro and in intact cells.
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Affiliation(s)
- Sima Lev
- Molecular Cell Biology Department, Weizmann Institute of Science, Rehovot 76100, Israel.
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Affiliation(s)
- Gregory D Fairn
- Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario M5B 1W8, Canada
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Waugh MG. Phosphatidylinositol 4-kinases, phosphatidylinositol 4-phosphate and cancer. Cancer Lett 2012; 325:125-31. [PMID: 22750097 DOI: 10.1016/j.canlet.2012.06.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/20/2012] [Accepted: 06/24/2012] [Indexed: 12/19/2022]
Abstract
This article focuses on the emerging roles for phosphatidylinositol 4-phosphate and the phosphatidylinositol 4-kinases in cancer. Phosphatidylinositol 4-phosphate is a common substrate for both the phosphatidylinositol 3-kinase and phospholipase C pathways, and has been implicated in the membrane targeting of proteins such as Girdin/GIV and OSBP. Alterations to phosphatidylinositol 4-kinase expression levels can modulate MAP kinase and Akt signalling, and are important for chemoresistance, tumour angiogenesis and the suppression of apoptosis and metastases. Recent improvements in high-throughput screening assays, and the discoveries that some anti-viral molecules are isoform selective phosphatidylinositol 4-kinase inhibitors have advanced the drugability of these enzymes.
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Affiliation(s)
- Mark G Waugh
- UCL Institute of Liver and Digestive Health, Royal Free Campus, London, United Kingdom.
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Devising Powerful Genetics, Biochemical and Structural Tools in the Functional Analysis of Phosphatidylinositol Transfer Proteins (PITPs) Across Diverse Species. Methods Cell Biol 2012; 108:249-302. [DOI: 10.1016/b978-0-12-386487-1.00013-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Cockcroft S, Garner K. Function of the phosphatidylinositol transfer protein gene family: is phosphatidylinositol transfer the mechanism of action? Crit Rev Biochem Mol Biol 2011; 46:89-117. [DOI: 10.3109/10409238.2010.538664] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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37
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Nile AH, Bankaitis VA, Grabon A. Mammalian diseases of phosphatidylinositol transfer proteins and their homologs. CLINICAL LIPIDOLOGY 2010; 5:867-897. [PMID: 21603057 PMCID: PMC3097519 DOI: 10.2217/clp.10.67] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Inositol and phosphoinositide signaling pathways represent major regulatory systems in eukaryotes. The physiological importance of these pathways is amply demonstrated by the variety of diseases that involve derangements in individual steps in inositide and phosphoinositide production and degradation. These diseases include numerous cancers, lipodystrophies and neurological syndromes. Phosphatidylinositol transfer proteins (PITPs) are emerging as fascinating regulators of phosphoinositide metabolism. Recent advances identify PITPs (and PITP-like proteins) to be coincidence detectors, which spatially and temporally coordinate the activities of diverse aspects of the cellular lipid metabolome with phosphoinositide signaling. These insights are providing new ideas regarding mechanisms of inherited mammalian diseases associated with derangements in the activities of PITPs and PITP-like proteins.
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Affiliation(s)
- Aaron H Nile
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Vytas A Bankaitis
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
| | - Aby Grabon
- Department of Cell & Developmental Biology, Lineberger Comprehensive Cancer Center School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-27090, USA
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Cyclooxygenase-2 in tumorigenesis of gastrointestinal cancers: an update on the molecular mechanisms. Cancer Lett 2010; 295:7-16. [PMID: 20381235 DOI: 10.1016/j.canlet.2010.03.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/18/2010] [Accepted: 03/22/2010] [Indexed: 12/20/2022]
Abstract
The use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with lower risks for esophageal, gastric and colon cancers as well as other solid tumors. The antitumor effect of NSAIDs is mediated through cyclooxygenase-2 (COX-2)-dependent and -independent regulation of oncogenic and tumor-suppressive pathways. Recent discoveries have shed new light on the regulation of COX-2 at the molecular level in these cancers. Moreover, prostaglandin E(2) (PGE(2)), a COX-2-derived eicosanoid, has been found to affect numerous tumorigenic processes. In this connection, PGE(2) activates multiple intracellular signaling pathways, including (1) transactivation of epidermal growth factor receptor (EGFR); (2) protein kinase C-dependent, EGFR-independent activation of extracellular signal-regulated kinase (ERK) and the transcription factors activator protein-1 and c-Myc; (3) G-protein-mediated activation of beta-catenin/TCF-dependent transcription. Activation of these signaling pathways by PGE(2) is mediated by EP receptors whose inhibitors suppress gastrointestinal carcinogenesis. Taken together, COX-2 expression is dysregulated in many types of cancer and COX-2-derived PGE(2) elicits multiple oncogenic signals to promote carcinogenesis. Targeting PGE(2) signaling by EP receptor antagonists holds promise for the development of targeted therapy for the treatment of cancer.
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Quantification of multiple phosphatidylinositol 4-kinase isozyme activities in cell extracts. Methods Mol Biol 2009; 462:279-89. [PMID: 19160677 DOI: 10.1007/978-1-60327-115-8_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
A wide spectrum of intracellular signaling events mediated by up to seven different phosphorylated forms of phosphatidylinositol (PtdIns) occurs in all eukaryotic cells. The activities of multiple, nondegenerate PI kinases and phosphatases control these signaling events. The PI 4-kinase isozymes account for the major PI kinase activity in many different cell types, and the activity of each isozyme is differentially regulated. The ability to measure and distinguish the activity of individual enzymes is therefore important and forms the subject of the methods in this chapter. We describe the use and application of a versatile radiometric assay to measuring PI 4-kinase activity in a variety of biochemical contexts, from purified enzymes to membrane preparations and permeabilized cells. Until a suitable nonradioactive reagent becomes available, this assay is destined to remain the most widely used method.
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Lee CS, Kang KR, Lee JY, Park CS, Hahn KH, Sohn JW, Kim BJ. Proteomic analysis of rat brains following exposure to electroconvulsive therapy. J Korean Med Sci 2009; 24:132-7. [PMID: 19270826 PMCID: PMC2650984 DOI: 10.3346/jkms.2009.24.1.132] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Accepted: 06/03/2008] [Indexed: 11/30/2022] Open
Abstract
Electroconvulsive therapy (ECT) is one of the most effective treatments used in psychiatry to date. The mechanisms of ECT action, however, are the least understood and still unclear. As a tool to elucidate the mechanisms of action of ECT, we employed proteomic analysis based on the identification of differentially expressed proteins after exposure to repeated ECT in rat brains. The expression of proteins was visualized by silver stain after two-dimensional gel electrophoresis. Of 24 differentially expressed protein spots (p<0.05 by Student t-test), six different proteins from 7 spots were identified by matrix-assisted laser desorption/ionization time-of flight (MALDI-TOF)/mass spectrometry. Among the identified proteins, there were five dominantly expressed proteins in the ECT-treated rat brain tissues (p<0.05); S100 protein beta chain, 14-3-3 protein zeta/delta, similar to ubiquitin-like 1 (sentrin) activating enzyme subunit 1, suppressor of G2 allele of SKP1 homolog, and phosphatidylinositol transfer protein alpha. The expression of only one protein, ACY1 protein, was repressed (p<0.05). These findings likely serve for a better understanding of mechanisms involved in the therapeutic effects of ECT.
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Affiliation(s)
- Cheol Soon Lee
- Department of Psychiatry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Kee Ryeon Kang
- Department of Biochemistry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
- MRC for Neural Dysfunction, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Ji-Young Lee
- Department of Biochemistry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
- MRC for Neural Dysfunction, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Chul Soo Park
- Department of Psychiatry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Kyu Hee Hahn
- Department of Psychiatry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Jin Wook Sohn
- Department of Psychiatry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
| | - Bong Jo Kim
- Department of Psychiatry, College of Medicine and Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
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Shadan S, Holic R, Carvou N, Ee P, Li M, Murray-Rust J, Cockcroft S. Dynamics of lipid transfer by phosphatidylinositol transfer proteins in cells. Traffic 2008; 9:1743-56. [PMID: 18636990 PMCID: PMC2635478 DOI: 10.1111/j.1600-0854.2008.00794.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Of many lipid transfer proteins identified, all have been implicated in essential cellular processes, but the activity of none has been demonstrated in intact cells. Among these, phosphatidylinositol transfer proteins (PITP) are of particular interest as they can bind to and transfer phosphatidylinositol (PtdIns) – the precursor of important signalling molecules, phosphoinositides – and because they have essential functions in neuronal development (PITPα) and cytokinesis (PITPβ). Structural analysis indicates that, in the cytosol, PITPs are in a ‘closed’ conformation completely shielding the lipid within them. But during lipid exchange at the membrane, they must transiently ‘open’. To study PITP dynamics in intact cells, we chemically targeted their C95 residue that, although non-essential for lipid transfer, is buried within the phospholipid-binding cavity, and so, its chemical modification prevents PtdIns binding because of steric hindrance. This treatment resulted in entrapment of open conformation PITPs at the membrane and inactivation of the cytosolic pool of PITPs within few minutes. PITP isoforms were differentially inactivated with the dynamics of PITPβ faster than PITPα. We identify two tryptophan residues essential for membrane docking of PITPs.
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Affiliation(s)
- Sadaf Shadan
- Department of Cell and Developmental Biology, Lipid Signalling Group, University College London, London, UK
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42
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D'Angelo G, Vicinanza M, De Matteis MA. Lipid-transfer proteins in biosynthetic pathways. Curr Opin Cell Biol 2008; 20:360-70. [PMID: 18490149 DOI: 10.1016/j.ceb.2008.03.013] [Citation(s) in RCA: 233] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 03/19/2008] [Accepted: 03/20/2008] [Indexed: 11/19/2022]
Abstract
Compartmentalization is a defining feature of eukaryotic cells that allows the spatial segregation of different functions, such as protein and lipid synthesis, and ensures their fidelity and efficiency. This imposes the need for an intense flux of metabolic intermediates between segregated enzymatic activities, as seen for the sequential transport of neosynthesized proteins through the segments of the secretory pathway during their post-translational modification. For lipid synthesis, the identification of proteins that transfer lipids between membranes has revealed an additional mechanism for this intercompartment exchange. The intense interest elicited by the lipid-transfer proteins over the last few years has led to the definition of their central role in key processes, such as lipid metabolism, membrane trafficking, and signaling.
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Affiliation(s)
- Giovanni D'Angelo
- Department of Cell Biology and Oncology, Consorzio Mario Negri Sud, 66030 Santa Maria Imbaro Chieti, Italy
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43
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Liu X, Wu WKK, Yu L, Li ZJ, Sung JJY, Zhang ST, Cho CH. Epidermal growth factor-induced esophageal cancer cell proliferation requires transactivation of beta-adrenoceptors. J Pharmacol Exp Ther 2008; 326:69-75. [PMID: 18369180 DOI: 10.1124/jpet.107.134528] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Unchecked mitogenic signals due to the overexpression of epidermal growth factor (EGF) and its receptor (EGFR) is implicated in the promotion and progression of cancer. In addition, beta-adrenoceptor is involved in the control of cancer cell proliferation. This study sought to elucidate whether a functional connection exists between these two disparate receptor systems. EGF was used to stimulate HKESC-1 cells, an esophageal squamous cancer cell line, in which beta-adrenoceptor activity was monitored by measuring intracellular cAMP levels in the absence or presence of beta-adrenoceptor antagonists. Results showed that EGF significantly increased cAMP levels and cell proliferation, both of which were attenuated by atenolol [(+)-4-[2-hydroxy-3-[(1-methylethyl)amino]propoxy]benzeneacetamide] or ICI 118,551 [(+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol], which are antagonists for the beta-adrenoceptor. Further mechanistic investigation revealed that the cellular release of epinephrine and the expression of its synthesizing enzyme tyrosine hydroxylase were induced by EGF. The expression of beta(1)-adrenoceptor and the downstream signal transducer protein kinase A were also up-regulated. In this connection, AG1478 [4-(3-chloroanilino)-6,7-dimethoxyquinazoline], an EGFR tyrosine kinase inhibitor, abrogated all these EGF-elicited alteration. Collectively, this study demonstrates that beta-adrenergic signaling could be up-regulated at multiple levels upon EGFR activation to mediate the mitogenic signals in esophageal cancer cells. This novel finding not only unveils the sinister liaison between EGFR and beta-adrenoceptors but also sheds new light on the purported therapeutic use of beta-adrenoceptor antagonists in the treatment of esophageal cancer.
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Affiliation(s)
- Xuan Liu
- Beijing Digestive Diseases Center and Beijing Friendship Hospital, Capital Medical University, Beijing, China
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Nakano M, Fukuda M, Kudo T, Endo H, Handa T. Determination of interbilayer and transbilayer lipid transfers by time-resolved small-angle neutron scattering. PHYSICAL REVIEW LETTERS 2007; 98:238101. [PMID: 17677937 DOI: 10.1103/physrevlett.98.238101] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Indexed: 05/05/2023]
Abstract
We applied a time-resolved small-angle neutron scattering technique to the vesicle system of dimyristoylphosphatidylcholine for the first time to determine lipid kinetics. The observed kinetics could be explicitly represented by a simple model that includes two independent kinetic parameters, i.e., the rates of transbilayer and interbilayer exchange. This technique is perfectly suited for the determination of lipid exchange kinetics in equilibrium and applicable to evaluation of the activity of the factors relevant to lipid migration, such as translocase and lipid transfer proteins.
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Affiliation(s)
- Minoru Nakano
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
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Cockcroft S, Carvou N. Biochemical and biological functions of class I phosphatidylinositol transfer proteins. Biochim Biophys Acta Mol Cell Biol Lipids 2007; 1771:677-91. [PMID: 17490911 DOI: 10.1016/j.bbalip.2007.03.009] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 03/05/2007] [Accepted: 03/27/2007] [Indexed: 12/21/2022]
Abstract
Phosphoinositides function in a diverse array of cellular activities. They include a role as substrate for lipid kinases and phospholipases to generate second messengers, regulators of the cytoskeleton, of enzymes and of ion channels, and docking sites for reversible recruitment of proteins to membranes. Mammalian phosphatidylinositol transfer proteins, PITPalpha and PITPbeta are paralogs that share 77% sequence identity and contain a hydrophobic cavity that can sequester either phosphatidylinositol or phosphatidylcholine. A string of 11 amino acid residues at the C-terminal acts as a "lid" which shields the lipid from the aqueous environment. PITPs in vitro can facilitate inter-membrane lipid transfer and this requires the movement of the "lid" to allow the lipid cargo to be released. Thus PITPs are structurally designed for delivering lipid cargo and could thus participate in cellular events that are dependent on phosphatidylinositol or derivatives of phosphatidylinositol. Phosphatidylinositol, the precursor for all phosphoinositides is synthesised at the endoplasmic reticulum and its distribution to other organelles could be facilitated by PITPs. Here we highlight recent studies that report on the three-dimensional structures of the different PITP forms and suggest how PITPs are likely to dock at the membrane surface for lipid delivery and extraction. Additionally we discuss whether PITPs are important regulators of sphingomyelin metabolism, and finally describe recent studies that link the association of PITPs with diverse functions including membrane traffic at the Golgi, neurite outgrowth, cytokinesis and stem cell growth.
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Affiliation(s)
- Shamshad Cockcroft
- Department of Physiology, 21 University Street, University College London, London WC1E 6JJ, UK.
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Su YC, Lu D, Tan XD, Dong AR, Tian HY, Luo SQ, Deng QK. Mathematical model of phosphatidylinositol-4,5-bisphosphate hydrolysis mediated by epidermal growth factor receptor generating diacylglycerol. J Biotechnol 2006; 124:574-91. [PMID: 16533541 DOI: 10.1016/j.jbiotec.2006.01.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 01/07/2006] [Accepted: 01/20/2006] [Indexed: 10/24/2022]
Abstract
Phosphatidylinositol-4,5-bisphosphate (PIP2) is hydrolyzed in response to the tyrosine phosphorylation of the epidermal growth factor receptor (EGFR) and plays an important role in regulating cell proliferation and differentiation through the generation of second messengers diacylglycerol (DAG) and trisphosphate inositol (IP3) which lead to the activation of protein kinase C (PKC) and increased levels of intracellular calcium, respectively. In the paper, a mathematical model was established to simulate the accumulation of DAG due to PIP2 hydrolysis mediated by EGFR. Molecular mechanisms between DAG, PIP2, EGFR and phosphatidylinositol transfer protein (PITP) were explained successfully, and positive cooperativity which existed between phospholipase C-gamma1 (PLC-gamma1) and PIP2 was also explained. In the model the effects of parameters on simulation of PIP2 hydrolysis were analyzed and the efficacies of some molecular intervention strategies were predicted. To test the coherence between the model and the biological response to epidermal growth factor (EGF) in cells, the levels of DAG and the tyrosine phosphorylation-EGFRs in NIH3T3 mouse embryonic fibroblast (MEF) were determined by biochemical experiments which showed that the accumulation of DAG was a sigmoidal function of phosphorylation-EGFR concentration, and the consistency between the mathematical model and experimental results was confirmed. In brief, this mathematical model provided a new idea for the further study of the dynamic change of biological characteristics in inositol phospholipid hydrolysis, predicting the efficacy of molecular intervention and the relationship between the metabolisms of inositol phospholipid and other signal transduction pathways.
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Affiliation(s)
- Yong-chun Su
- Department of Medical Physics, South Medical University, Guangzhou 510515, PR China
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Chalimoniuk M, Snoek GT, Adamczyk A, Małecki A, Strosznajder JB. Phosphatidylinositol Transfer Protein Expression Altered by Aging and Parkinson Disease. Cell Mol Neurobiol 2006; 26:1153-66. [PMID: 16779671 DOI: 10.1007/s10571-006-9078-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 04/24/2006] [Indexed: 10/24/2022]
Abstract
1. Phosphatidylinositol transfer proteins (PI-TP) are responsible for the transport of phosphatidylinositol (PI) and other phospholipids from endoplasmic reticulum to the other membranes and indirectly for lipid mediated signaling. Till now little is known about PI-TPs in brain aging and neurodegeneration. The aim of this study was to investigate expression of PI-TP in the brain during aging and in animal's model of Parkinson disease (PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Moreover, in vitro, effect of 1-methyl-4-phenyl-pyridine cation (MPP(+)) on PI-TP, tyrosine hydroxylase (TH) protein level, and viability of cells was investigated. 2. Wistar rats 4, 24, and 36 months old and C57/BL mice and rat pheochromocytoma (PC12) cell line were used for the studies. Mice C57/BL received three injections of MPTP in saline at 2 h intervals in a total dose of 40 mg/kg and then after 3, 7, and 14 days they were used for the investigation. PC12 cells were treated with increasing concentration (50-300 microM) of MPP(+) for 24 h at 37 degrees C. The level of PI-TP(alpha and beta) and TH were determined using Western Blot analysis. 3. Our data indicated that PI-TP(alpha and beta) level decreased in brain of 36 months old rat by 20% comparing to the control value (4 months old). In animal's model of PD, PI-TP(alpha and beta) level was significantly lower by 85, 69, 64% in striatum at 3, 7, and 14 days after MPTP injection, respectively, compared to the control value. MPP(+) decreased PI-TP(alpha and beta), TH expression, and viability of PC12 cells in a dose-dependent manner. H(2)O(2), menadione, and NO donor significantly decreased the PI-TP level and viability of PC12 cells. 4. Our results indicate the lower protein expression of PI-TP(alpha and beta) in aged brain and in PD and suggest that oxidative stress may be responsible for the alteration of PI-TP.
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Affiliation(s)
- Małgorzata Chalimoniuk
- Medical Research Center, Department of Cellular Signaling, Polish Academy of Sciences, 5 Pawińskiego St., 02-106, Warsaw, Poland.
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48
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Peterman TK, Ohol YM, McReynolds LJ, Luna EJ. Patellin1, a novel Sec14-like protein, localizes to the cell plate and binds phosphoinositides. PLANT PHYSIOLOGY 2004; 136:3080-94; discussion 3001-2. [PMID: 15466235 PMCID: PMC523369 DOI: 10.1104/pp.104.045369] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Revised: 07/23/2004] [Accepted: 07/23/2004] [Indexed: 05/19/2023]
Abstract
Membrane trafficking is central to construction of the cell plate during plant cytokinesis. Consequently, a detailed understanding of the process depends on the characterization of molecules that function in the formation, transport, targeting, and fusion of membrane vesicles to the developing plate, as well as those that participate in its consolidation and maturation into a fully functional partition. Here we report the initial biochemical and functional characterization of patellin1 (PATL1), a novel cell-plate-associated protein that is related in sequence to proteins involved in membrane trafficking in other eukaryotes. Analysis of the Arabidopsis genome indicated that PATL1 is one of a small family of Arabidopsis proteins, characterized by a variable N-terminal domain followed by two domains found in other membrane-trafficking proteins (Sec14 and Golgi dynamics domains). Results from immunolocalization and biochemical fractionation studies suggested that PATL1 is recruited from the cytoplasm to the expanding and maturing cell plate. In vesicle-binding assays, PATL1 bound to specific phosphoinositides, important regulators of membrane trafficking, with a preference for phosphatidylinositol(5)P, phosphatidylinositol(4,5)P(2), and phosphatidylinositol(3)P. Taken together, these findings suggest a role for PATL1 in membrane-trafficking events associated with cell-plate expansion or maturation and point to the involvement of phosphoinositides in cell-plate biogenesis.
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Affiliation(s)
- T Kaye Peterman
- Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts 02481, USA.
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Morgan CP, Skippen A, Segui B, Ball A, Allen-Baume V, Larijani B, Murray-Rust J, McDonald N, Sapkota G, Morrice N, Cockcroft S. Phosphorylation of a distinct structural form of phosphatidylinositol transfer protein alpha at Ser166 by protein kinase C disrupts receptor-mediated phospholipase C signaling by inhibiting delivery of phosphatidylinositol to membranes. J Biol Chem 2004; 279:47159-71. [PMID: 15322105 DOI: 10.1074/jbc.m405827200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphatidylinositol transfer protein alpha (PITPalpha) participates in the supply of phosphatidylinositol (PI) required for many cellular events including phospholipase C (PLC) beta and gamma signaling by G-protein-coupled receptors and receptor-tyrosine kinases, respectively. Protein kinase C has been known to modulate PLC signaling by G-protein-coupled receptors and receptor-tyrosine kinases, although the molecular target has not been identified in most instances. In each case phorbol myristate acetate pretreatment of HL60, HeLa, and COS-7 cells abrogated PLC stimulation by the agonists formyl-Met-Leu-Phe, ATP, and epidermal growth factor, respectively. Here we show that phosphorylation of PITPalpha at Ser166 resulted in inhibition of receptor-stimulated PLC activity. Ser166 is localized in a small pocket between the 165-172 loop and the rest of the protein and was not solvent-accessible in either the PI- or phosphatidylcholine-loaded structures of PITPalpha. To allow phosphorylation at Ser166, a distinct structural form is postulated, and mutation of Thr59 to alanine shifted the equilibrium to this form, which could be resolved on native PAGE. The elution profile observed by size exclusion chromatography of phosphorylated PITPalpha from rat brain or in vitro phosphorylated PITPalpha demonstrated that phosphorylated PITPalpha is structurally distinct from the non-phosphorylated form. Phosphorylated PITPalpha was unable to deliver its PI cargo, although it could deliver phosphatidylcholine. We conclude that the PITPalpha structure has to relax to allow access to the Ser166 site, and this may occur at the membrane surface where PI delivery is required for receptor-mediated PLC signaling.
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Affiliation(s)
- Clive P Morgan
- Department of Physiology, University College London, London WC1E 6JJ
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Olayioye MA, Hoffmann P, Pomorski T, Armes J, Simpson RJ, Kemp BE, Lindeman GJ, Visvader JE. The phosphoprotein StarD10 is overexpressed in breast cancer and cooperates with ErbB receptors in cellular transformation. Cancer Res 2004; 64:3538-44. [PMID: 15150109 DOI: 10.1158/0008-5472.can-03-3731] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have identified that StarD10, a member of the START protein family, is overexpressed in both mouse and human breast tumors. StarD10 was initially discovered on the basis of its cross-reactivity with a phosphoserine-specific antibody in mammary tumors from Neu/ErbB2 transgenic mice and subsequently isolated from SKBR3 human breast carcinoma cells using a multistep biochemical purification strategy. We have shown that StarD10 is capable of binding lipids. StarD10 was found to be overexpressed in 35% of primary breast carcinomas and 64% of human breast cancer cell lines, correlating with their ErbB2/Her2 status. Coexpression of StarD10 with ErbB1/epidermal growth factor receptor in murine fibroblasts enhanced anchorage-independent growth in soft agar, providing evidence for functional cooperation between StarD10 and ErbB receptor signaling. Taken together, these data suggest that overexpression of this lipid-binding protein contributes to breast oncogenesis.
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Affiliation(s)
- Monilola A Olayioye
- The Walter and Eliza Hall Institute of Medical Research and Bone Marrow Research Laboratories, Royal Melbourne Hospital, Parkville, Victoria, Australia
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