TRPC1 proteins confer PKC and phosphoinositol activation on native heteromeric TRPC1/C5 channels in vascular smooth muscle:Comparative study of wild-type and TRPC1 -/- mice

Shi, Jian, Ju, Min, Abramowitz, Joel, Large, William A., Birnbaumer, Lutz and Albert, Anthony P. ORCID: https://orcid.org/0000-0002-3596-9634 (2012) TRPC1 proteins confer PKC and phosphoinositol activation on native heteromeric TRPC1/C5 channels in vascular smooth muscle:Comparative study of wild-type and TRPC1 -/- mice. FASEB Journal, 26 (1). pp. 409-419. ISSN 0892-6638

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Abstract

Ca 2+-permeable cation channels consisting of canonical transient receptor potential 1 (TRPC1) proteins mediate Ca 2+ influx pathways in vascular smooth muscle cells (VSMCs), which regulate physiological and pathological functions. We investigated properties conferred by TRPC1 proteins to native single TRPC channels in acutely isolated mesenteric artery VSMCs from wildtype (WT) and TRPC1-deficient (TRPC1 -/-) mice using patch-clamp techniques. In WT VSMCs, the intracellular Ca 2+ store-depleting agents cyclopiazonic acid (CPA) and 1,2-bis-(2-aminophenoxy)ethane-N,N,N′, N′-tetraacetic acid (BAPTA-AM) both evoked channel currents, which had unitary conductances of ∼2 pS. In TRPC1 -/- VSMCs, CPA-induced channel currents had 3 subconductance states of 14, 32, and 53 pS. Passive depletion of intracellular Ca 2+ stores activated whole-cell cation currents in WT but not TRPC1 -/- VSMCs. Differential blocking actions of anti-TRPC antibodies and coimmunoprecipitation studies revealed that CPA induced heteromeric TRPC1/C5 channels in WT VSMCs and TRPC5 channels in TRPC1 -/- VSMCs. CPA-evoked TRPC1/C5 channel activity was prevented by the protein kinase C (PKC) inhibitor chelerythrine. In addition, the PKC activator phorbol 12,13-dibutyrate (PDBu), a PKC catalytic subunit, and phosphatidylinositol-4,5-bisphosphate (PIP 2) and phosphatidylinositol-3,4,5-trisphosphate (PIP 3) activated TRPC1/C5 channel activity, which was prevented by chelerythrine. In contrast, CPA-evoked TRPC5 channel activity was potentiated by chelerythrine, and inhibited by PDBu, PIP 2, and PIP 3. TRPC5 channels in TRPC1 -/-VSMCs were activated by increasing intracellular Ca 2+concentrations ([Ca 2+] i), whereas increasing [Ca 2+] i had no effect in WT VSMCs. We conclude that agents that deplete intracellular Ca 2+ stores activate native heteromeric TRPC1/C5 channels in VSMCs, and that TRPC1 subunits are important in determining unitary conductance and conferring channel activation by PKC, PIP 2, and PIP 3.

Item Type: Article
Uncontrolled Keywords: ca signaling,hypertension,transgenic,biotechnology,biochemistry,molecular biology,genetics ,/dk/atira/pure/subjectarea/asjc/1300/1305
Faculty \ School: Faculty of Medicine and Health Sciences > Norwich Medical School
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Depositing User: LivePure Connector
Date Deposited: 29 Oct 2024 09:30
Last Modified: 04 Nov 2024 10:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/97260
DOI: 10.1096/fj.11-185611

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