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Shi, Jian, Miralles, Francesc, Kinet, Jean Pierre, Birnbaumer, Lutz, Large, William A. and Albert, Anthony P. 
ORCID: https://orcid.org/0000-0002-3596-9634
(2017)
Evidence that Orai1 does not contribute to store-operated TRPC1 channels in vascular smooth muscle cells.
Channels, 11 (4).
pp. 329-339.
ISSN 1933-6950
Abstract
Ca2+-permeable store-operated channels (SOCs) mediate Ca2+ entry pathways which are involved in many cellular functions such as contraction, growth, and proliferation. Prototypical SOCs are formed of Orai1 proteins and are activated by the endo/sarcoplasmic reticulum Ca2+ sensor stromal interaction molecule 1 (STIM1). There is considerable debate about whether canonical transient receptor potential 1 (TRPC1) proteins also form store-operated channels (SOCs), and if they do, is Orai1 involved. We recently showed that stimulation of TRPC1-based SOCs involves store depletion inducing STIM1-evoked Gαq/PLCβ1 activity in contractile vascular smooth muscle cells (VSMCs). Therefore the present work investigates the role of Orai1 in activation of TRPC1-based SOCs in freshly isolated mesenteric artery VSMCs from wild-type (WT) and Orai1−/− mice. Store-operated whole-cell and single channel currents recorded from WT and Orai1−/− VSMCs had similar properties, with relatively linear current-voltage relationships, reversal potentials of about +20mV, unitary conductances of about 2pS, and inhibition by anti-TRPC1 and anti-STIM1 antibodies. In Orai1−/− VSMCs, store depletion induced PLCβ1 activity measured with the fluorescent phosphatidylinositol 4,5-bisphosphate/inositol 1,4,5-trisphosphate biosensor GFP-PLCδ1-PH, which was prevented by knockdown of STIM1. In addition, in Orai1−/− VSMCs, store depletion induced translocation of STIM1 from within the cell to the plasma membrane where it formed STIM1-TRPC1 interactions at discrete puncta-like sites. These findings indicate that activation of TRPC1-based SOCs through a STIM1-activated PLCβ1 pathway are likely to occur independently of Orai1 proteins, providing evidence that TRPC1 channels form genuine SOCs in VSMCs with a contractile phenotype.
| Item Type: | Article |
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| Additional Information: | Funding Information: We would like to thank Dr Paris Ataliotis for his assistance with genotyping. This work was supported by the Biotechnology and Biological Sciences Research Council (BB/J007226/1 and BB/M018350/1 to APA) and was also supported in part by the NIH Intramural Research Program (Project Z01-ES-101684 to L.B). Funding Information: This work was supported by the Biotechnology and Biological Sciences Research Council (BB/J007226/1 and BB/M018350/1 to APA) and was also supported in part by the NIH Intramural Research Program (Project Z01-ES-101684 to L.B). Publisher Copyright: © 2017 St. George's, University of London. Published with license by Taylor & Francis. |
| Uncontrolled Keywords: | orai1,plc,stim1,store-operated,trpc1,vascular smooth muscle,biophysics,biochemistry ,/dk/atira/pure/subjectarea/asjc/1300/1304 |
| Faculty \ School: | Faculty of Medicine and Health Sciences > Norwich Medical School |
| Related URLs: | |
| Depositing User: | LivePure Connector |
| Date Deposited: | 29 Oct 2024 09:30 |
| Last Modified: | 12 Nov 2024 14:30 |
| URI: | https://ueaeprints.uea.ac.uk/id/eprint/97246 |
| DOI: | 10.1080/19336950.2017.1303025 |
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