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Obligatory role for phosphatidylinositol 4,5-bisphosphate in activation of native TRPC1 store-operated channels in vascular myocytes

Saleh, SN; Albert, AP; Large, WA (2009) Obligatory role for phosphatidylinositol 4,5-bisphosphate in activation of native TRPC1 store-operated channels in vascular myocytes. JOURNAL OF PHYSIOLOGY-LONDON, 587 (3). 531 - 540. ISSN 0022-3751
SGUL Authors: Albert, Anthony Paul Large, William Abbott

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In the present study the effect of phosphatidylinositol 4,5-bisphosphate (PIP2) was studied on a native TRPC1 store-operated channel (SOC) in freshly dispersed rabbit portal vein myocytes. Application of diC8-PIP2, a water soluble form of PIP2, to quiescent inside-out patches evoked single channel currents with a unitary conductance of 1.9 pS. DiC8-PIP2-evoked channel currentswere inhibited by anti-TRPC1 antibodies and these characteristics are identical to SOCs evoked by cyclopiazonic acid (CPA) and BAPTA-AM. SOCs stimulated by CPA, BAPTA-AM and the phorbol ester phorbol 12,13-dibutyrate (PDBu) were reduced by anti-PIP2 antibodies and by depletion of tissue PIP2 levels by pre-treatment of preparations with wortmannin and LY294002. However, these reagents did not alter the ability of PIP2 to activate SOCs in inside-out patches. Co-immunoprecipitation techniques demonstrated association between TRPC1 and PIP2 at rest, which was greatly decreased by wortmannin and LY294002. Pre-treatment of cells with PDBu, which activates protein kinase C (PKC), augmented SOC activation by PIP2 whereas the PKC inhibitor chelerythrine decreased SOC stimulation by PIP2. Co-immunoprecipitation experiments provide evidence that PKC-dependent phosphorylation of TRPC1 occurs constitutively and was increased by CPA and PDBu but decreased by chelerythrine. These novel results show that PIP2 can activate TRPC1 SOCs in native vascular myocytes and plays an important role in SOC activation by CPA, BAPTA-AM and PDBu. Moreover, the permissive role of PIP2 in SOC activation requires PKC-dependent phosphorylation of TRPC1.

Item Type: Article
Additional Information: Copyright © 2009 The Authors. Journal compilation © 2009 The Physiological Society. Published under Wiley Online Open program. The published article is deposited by Wiley into PubMed Central, with no embargo, and the article can also be deposited into other non-commercial subject or institutional repositories.
Keywords: 1-Phosphatidylinositol 4-Kinase, Androstadienes, Animals, Antibodies, Phospho-Specific, Benzophenanthridines, Chelating Agents, Chromones, Egtazic Acid, Immunologic Factors, Immunoprecipitation, Indoles, Membrane Potentials, Morpholines, Myocytes, Smooth Muscle, Phosphatidylinositol 4,5-Diphosphate, Portal Vein, Protein Kinase C, Protein Kinase Inhibitors, Rabbits, TRPC Cation Channels, Science & Technology, Life Sciences & Biomedicine, Neurosciences, Physiology, Neurosciences & Neurology, CA2+-PERMEABLE CATION CHANNEL, PORTAL-VEIN MYOCYTES, PROTEIN-KINASE-C, CARDIAC NA+/CA2+ EXCHANGER, MESENTERIC-ARTERY MYOCYTES, SMOOTH-MUSCLE-CELLS, CALCIUM INFLUX, MECHANISMS, ENTRY
SGUL Research Institute / Research Centre: Academic Structure > Molecular and Clinical Sciences Research Institute (MCS) > Vascular (INCCVA)
Academic Structure > Institute of Medical & Biomedical Education (IMBE) > Centre for Innovation & Development in Education (INMEID)
Journal or Publication Title: JOURNAL OF PHYSIOLOGY-LONDON
ISSN: 0022-3751
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1 February 2009Published
Web of Science ID: WOS:000262944900006
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