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Kučka M, Gonzalez-Iglesias AE, Tomić M, Prévide RM, Smiljanic K, Sokanovic SJ, Fletcher PA, Sherman A, Balla T, Stojilkovic SS. Calcium-Prolactin Secretion Coupling in Rat Pituitary Lactotrophs Is Controlled by PI4-Kinase Alpha. Front Endocrinol (Lausanne) 2021; 12:790441. [PMID: 35058881 PMCID: PMC8764672 DOI: 10.3389/fendo.2021.790441] [Citation(s) in RCA: 1] [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: 10/06/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
The role of calcium, but not of other intracellular signaling molecules, in the release of pituitary hormones by exocytosis is well established. Here, we analyzed the contribution of phosphatidylinositol kinases (PIKs) to calcium-driven prolactin (PRL) release in pituitary lactotrophs: PI4Ks - which control PI4P production, PIP5Ks - which synthesize PI(4, 5)P2 by phosphorylating the D-5 position of the inositol ring of PI4P, and PI3KCs - which phosphorylate PI(4, 5)P2 to generate PI(3, 4, 5)P3. We used common and PIK-specific inhibitors to evaluate the strength of calcium-secretion coupling in rat lactotrophs. Gene expression was analyzed by single-cell RNA sequencing and qRT-PCR analysis; intracellular and released hormones were assessed by radioimmunoassay and ELISA; and single-cell calcium signaling was recorded by Fura 2 imaging. Single-cell RNA sequencing revealed the expression of Pi4ka, Pi4kb, Pi4k2a, Pi4k2b, Pip5k1a, Pip5k1c, and Pik3ca, as well as Pikfyve and Pip4k2c, in lactotrophs. Wortmannin, a PI3K and PI4K inhibitor, but not LY294002, a PI3K inhibitor, blocked spontaneous action potential driven PRL release with a half-time of ~20 min when applied in 10 µM concentration, leading to accumulation of intracellular PRL content. Wortmannin also inhibited increase in PRL release by high potassium, the calcium channel agonist Bay K8644, and calcium mobilizing thyrotropin-releasing hormone without affecting accompanying calcium signaling. GSK-A1, a specific inhibitor of PI4KA, also inhibited calcium-driven PRL secretion without affecting calcium signaling and Prl expression. In contrast, PIK93, a specific inhibitor of PI4KB, and ISA2011B and UNC3230, specific inhibitors of PIP5K1A and PIP5K1C, respectively, did not affect PRL release. These experiments revealed a key role of PI4KA in calcium-secretion coupling in pituitary lactotrophs downstream of voltage-gated and PI(4, 5)P2-dependent calcium signaling.
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Affiliation(s)
- Marek Kučka
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Arturo E. Gonzalez-Iglesias
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Melanija Tomić
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Rafael M. Prévide
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Kosara Smiljanic
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Srdjan J. Sokanovic
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Patrick A. Fletcher
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Arthur Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD, United States
| | - Tamas Balla
- Section on Molecular Signal Transduction, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Stanko S. Stojilkovic
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
- *Correspondence: Stanko S. Stojilkovic,
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Ziyad S, Riordan JD, Cavanaugh AM, Su T, Hernandez GE, Hilfenhaus G, Morselli M, Huynh K, Wang K, Chen JN, Dupuy AJ, Iruela-Arispe ML. A Forward Genetic Screen Targeting the Endothelium Reveals a Regulatory Role for the Lipid Kinase Pi4ka in Myelo- and Erythropoiesis. Cell Rep 2019; 22:1211-1224. [PMID: 29386109 PMCID: PMC5828030 DOI: 10.1016/j.celrep.2018.01.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 11/05/2017] [Accepted: 01/05/2018] [Indexed: 11/19/2022] Open
Abstract
Given its role as the source of definitive hematopoietic cells, we sought to determine whether mutations initiated in the hemogenic endothelium would yield hematopoietic abnormalities or malignancies. Here, we find that endothelium-specific transposon mutagenesis in mice promotes hematopoietic pathologies that are both myeloid and lymphoid in nature. Frequently mutated genes included previously recognized cancer drivers and additional candidates, such as Pi4ka, a lipid kinase whose mutation was found to promote myeloid and erythroid dysfunction. Subsequent validation experiments showed that targeted inactivation of the Pi4ka catalytic domain or reduction in mRNA expression inhibited myeloid and erythroid cell differentiation in vitro and promoted anemia in vivo through a mechanism involving deregulation of AKT, MAPK, SRC, and JAK-STAT signaling. Finally, we provide evidence linking PI4KAP2, previously considered a pseudogene, to human myeloid and erythroid leukemia.
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Affiliation(s)
- Safiyyah Ziyad
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jesse D Riordan
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Ann M Cavanaugh
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Trent Su
- Institute for Quantitative and Computational Biology and Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Gloria E Hernandez
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Georg Hilfenhaus
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Marco Morselli
- Institute for Quantitative and Computational Biology and Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA 90095, USA; Institute of Genomics and Proteomics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kristine Huynh
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Kevin Wang
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Jau-Nian Chen
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Adam J Dupuy
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - M Luisa Iruela-Arispe
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, CA 90095, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA 90095, USA; Jonsson Comprehensive Cancer Center, University of California, Los Angeles, Los Angeles, CA 90095, USA.
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Type II PtdIns 4-kinase β associates with CD4-p56lck complex and is involved in CD4 receptor signaling. Mol Cell Biochem 2014; 395:231-9. [PMID: 24972704 DOI: 10.1007/s11010-014-2129-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 06/17/2014] [Indexed: 11/27/2022]
Abstract
Type II phosphatidylinositol (PtdIns) 4-kinases are involved in the synthesis of PtdIns 4-phosphates and modulate various cell functions like, intracellular signaling, cytoskeletal rearrangements, vesicular trafficking, and pathogen invasion. In CD3 receptor activated T cells, a type II PtdIns 4-kinase β is recruited to CD3 receptor zeta and plays a role in intracellular calcium release and probably in actin cytoskeleton reorganization. T cell receptor mediated activation is supported by CD4 receptor. The role of type II PtdIns 4-kinase β in CD4 receptor-mediated signaling was addressed in the present manuscript. Crosslinking of CD4 receptors with monoclonal antibodies showed an increase in CD4-associated PtdIns 4-kinase activity and requires p56(lck) activity. Biochemical characterization suggests that it belongs to type II PtdIns 4-kinase family. shRNA mediated knockdown of type II PtdIns 4-kinase β showed abrogation of CD4 receptor induced intracellular calcium release. These results suggest that type II PtdIns 4-kinase β plays an integral part in CD4 receptor-mediated signaling.
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Mapping of functional domains of the lipid kinase phosphatidylinositol 4-kinase type III alpha involved in enzymatic activity and hepatitis C virus replication. J Virol 2014; 88:9909-26. [PMID: 24920820 DOI: 10.1128/jvi.01063-14] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
UNLABELLED The lipid kinase phosphatidylinositol 4-kinase III alpha (PI4KIIIα) is an endoplasmic reticulum (ER)-resident enzyme that synthesizes phosphatidylinositol 4-phosphate (PI4P). PI4KIIIα is an essential host factor for hepatitis C virus (HCV) replication. Interaction with HCV nonstructural protein 5A (NS5A) leads to kinase activation and accumulation of PI4P at intracellular membranes. In this study, we investigated the structural requirements of PI4KIIIα in HCV replication and enzymatic activity. Therefore, we analyzed PI4KIIIα mutants for subcellular localization, reconstitution of HCV replication in PI4KIIIα knockdown cell lines, PI4P induction in HCV-positive cells, and lipid kinase activity in vitro. All mutants still interacted with NS5A and localized in a manner similar to that of the full-length enzyme, suggesting multiple regions of PI4KIIIα are involved in NS5A interaction and subcellular localization. Interestingly, the N-terminal 1,152 amino acids were dispensable for HCV replication, PI4P induction, and enzymatic function, whereas further N-terminal or C-terminal deletions were deleterious, thereby defining the minimal PI4KIIIα core enzyme at a size of ca. 108 kDa. Additional deletion of predicted functional motifs within the C-terminal half of PI4KIIIα also were detrimental for enzymatic activity and for the ability of PI4KIIIα to rescue HCV replication, with the exception of a proposed nuclear localization signal, suggesting that the entire C-terminal half of PI4KIIIα is involved in the formation of a minimal enzymatic core. This view was supported by structural modeling of the PI4KIIIα C terminus, suggesting a catalytic center formed by an N- and C-terminal lobe and an armadillo-fold motif, which is preceded by three distinct alpha-helical domains probably involved in regulation of enzymatic activity. IMPORTANCE The lipid kinase PI4KIIIα is of central importance for cellular phosphatidylinositol metabolism and is a key host cell factor of hepatitis C virus replication. However, little is known so far about the structure of this 240-kDa protein and the functional importance of specific subdomains regarding lipid kinase activity and viral replication. This work focuses on the phenotypic analysis of distinct PI4KIIIα mutants in different biochemical and cell-based assays and develops a structural model of the C-terminal enzymatic core. The results shed light on the structural and functional requirements of enzymatic activity and the determinants required for HCV replication.
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Bojjireddy N, Sinha RK, Subrahmanyam G. Piperine inhibits type II phosphatidylinositol 4-kinases: a key component in phosphoinositides turnover. Mol Cell Biochem 2014; 393:9-15. [DOI: 10.1007/s11010-014-2041-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 03/14/2014] [Indexed: 11/29/2022]
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Type II phosphatidylinositol 4-kinases interact with FcεRIγ subunit in RBL-2H3 cells. Mol Cell Biochem 2014; 390:197-203. [PMID: 24481753 DOI: 10.1007/s11010-014-1970-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
Abstract
Ligation of high-affinity IgE receptor I (FcεRI) on RBL-2H3 cells leads to recruitment of FcεRI and type II phosphatidylinositol 4-kinases (PtdIns 4-kinases) into lipid rafts. Lipid raft integrity is required for the activation of type II PtdIns 4-kinases and signal transduction through FcεRIγ during RBL-2H3 cell activation. However, the molecular mechanism by which PtdIns 4-kinases are coupled to FcεRI signaling is elusive. Here, we report association of type II PtdIns 4-kinase activity with FcεRIγ subunit in anti-FcεRIγ immunoprecipitates. FcεRIγ-associated PtdIns 4-kinase activity increases threefold upon FcεRI ligation in anti-FcεRIγ immunoprecipitates. Biochemical characterization of PtdIns 4-kinase activity associated with FcεRIγ reveals that it is a type II PtdIns 4-kinases. Canonical tyrosine residues mutation in FcεRIγ ITAM (Y65 and Y76) reveals that these two tyrosine residues in γ subunit are required for its interaction with type II PtdIns 4-kinases.
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Bojjireddy N, Sinha RK, Subrahmanyam G. Fyn kinase regulates type II PtdIns 4-kinases in RBL 2H3 cells. Mol Cell Biochem 2013; 387:63-70. [PMID: 24173619 DOI: 10.1007/s11010-013-1871-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 10/18/2013] [Indexed: 10/26/2022]
Abstract
Type II phosphatidylinositol 4-kinases are implicated in FcεRI-mediated signaling cascades leading to release of inflammatory molecules. Cross-linking of FcεRI on RBL 2H3 cells results in protein tyrosine phosphorylation and activation of type II PtdIns 4-kinase activity. Protein tyrosine kinase(s) that phosphorylate type II PtdIns 4-kinase(s) in RBL 2H3 cells remains elusive and is being addressed in this manuscript. Anti-Fyn kinase antibodies co-immunoprecipitated type II PtdIns 4-kinase activity from FcεRI cross-linked RBL 2H3 cells. In reciprocal assays, His-tagged types II PtdIns 4-kinases were shown to pull down Fyn kinase. Further, anti-Fyn immunoprecipitates were shown to phosphorylate type II PtdIns 4-kinase α and β in in vitro assays. Pull down studies with GST-Fyn-SH2 and GST-Fyn-SH3 domains showed that type II PtdIns 4-kinases associate with Fyn-SH2 domain. Knockdown of Fyn kinase in RBL 2H3 cells abrogated activation of type II PtdIns 4-kinase activity in response to FcεRI cross-linking and type II PtdIns 4-kinase activity in anti-phosphotyrosine immunoprecipitates. Knockdown of Fyn kinase was also strongly correlated with a reduction in β-hexosaminidase release in response to FcεRI cross-linking. These results suggest that type II PtdIns 4-kinases act downstream of Fyn kinase in FcεRI signaling cascades and are regulated by Fyn kinase.
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Affiliation(s)
- Naveen Bojjireddy
- Department of Biosciences and Bioengineering, Wadhwani Research Centre for Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, India,
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Sanguinarine suppresses IgE induced inflammatory responses through inhibition of type II PtdIns 4-kinase(s). Arch Biochem Biophys 2013; 537:192-7. [DOI: 10.1016/j.abb.2013.07.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/03/2013] [Accepted: 07/20/2013] [Indexed: 01/22/2023]
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9
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Sinha RK, Bojjireddy N, Kulkarni D, Ratheesh A, Chiplunkar S, Gude R, Subrahmanyam G. Type II phosphatidylinositol 4-kinase β is an integral signaling component of early T cell activation mechanisms. Biochimie 2013; 95:1560-6. [DOI: 10.1016/j.biochi.2013.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Accepted: 04/12/2013] [Indexed: 10/26/2022]
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10
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De Matteis MA, Wilson C, D'Angelo G. Phosphatidylinositol-4-phosphate: The Golgi and beyond. Bioessays 2013; 35:612-22. [DOI: 10.1002/bies.201200180] [Citation(s) in RCA: 260] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Cathal Wilson
- Telethon Institute of Genetics and Medicine; Naples; Italy
| | - Giovanni D'Angelo
- Institute of Protein Biochemistry; National Research Council (CNR); Naples; Italy
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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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Evaluation of phosphatidylinositol-4-kinase IIIα as a hepatitis C virus drug target. J Virol 2012; 86:11595-607. [PMID: 22896614 DOI: 10.1128/jvi.01320-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Phosphatidylinositol-4-kinase IIIα (PI4KIIIα) is an essential host cell factor for hepatitis C virus (HCV) replication. An N-terminally truncated 130-kDa form was used to reconstitute an in vitro biochemical lipid kinase assay that was optimized for small-molecule compound screening and identified potent and specific inhibitors. Cell culture studies with PI4KIIIα inhibitors demonstrated that the kinase activity was essential for HCV RNA replication. Two PI4KIIIα inhibitors were used to select cell lines harboring HCV replicon mutants with a 20-fold loss in sensitivity to the compounds. Reverse genetic mapping isolated an NS4B-NS5A segment that rescued HCV RNA replication in PIK4IIIα-deficient cells. HCV RNA replication occurs on specialized membranous webs, and this study with PIK4IIIα inhibitor-resistant mutants provides a genetic link between NS4B/NS5A functions and PI4-phosphate lipid metabolism. A comprehensive assessment of PI4KIIIα as a drug target included its evaluation for pharmacologic intervention in vivo through conditional transgenic murine lines that mimic target-specific inhibition in adult mice. Homozygotes that induce a knockout of the kinase domain or knock in a single amino acid substitution, kinase-defective PI4KIIIα, displayed a lethal phenotype with a fairly widespread mucosal epithelial degeneration of the gastrointestinal tract. This essential host physiologic role raises doubt about the pursuit of PI4KIIIα inhibitors for treatment of chronic HCV infection.
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Phosphatidylinositol 4-kinases: hostages harnessed to build panviral replication platforms. Trends Biochem Sci 2012; 37:293-302. [PMID: 22633842 PMCID: PMC3389303 DOI: 10.1016/j.tibs.2012.03.004] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 03/27/2012] [Accepted: 03/30/2012] [Indexed: 12/20/2022]
Abstract
Several RNA viruses have recently been shown to hijack members of the host phosphatidylinositol (PtdIns) 4-kinase (PI4K) family of enzymes. They use PI4K to generate membranes enriched in phosphatidylinositide 4-phosphate (PtdIns4P or PI4P) lipids, which can be used as replication platforms. Viral replication machinery is assembled on these platforms as a supramolecular complex and PtdIns4P lipids regulate viral RNA synthesis. This article highlights these recent studies on the regulation of viral RNA synthesis by PtdIns4P lipids. It explores the potential mechanisms by which PtdIns4P lipids can contribute to viral replication and discusses the therapeutic potential of developing antiviral molecules that target host PI4Ks as a form of panviral therapy.
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