The role of plasma membrane STIM1 and Ca2+entry in platelet aggregation. STIM1 binds to novel proteins in human platelets

Ambily, A., Kaiser, W. J., Pierro, C., Chamberlain, E. V., Li, Z., Jones, C. I., Kassouf, Nick ORCID: https://orcid.org/0000-0003-0519-1929, Gibbins, J. M. and Authi, K. S. (2014) The role of plasma membrane STIM1 and Ca2+entry in platelet aggregation. STIM1 binds to novel proteins in human platelets. Cellular Signalling, 26 (3) . pp. 502-511. ISSN 0898-6568 [Article] (doi:10.1016/j.cellsig.2013.11.025)

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Abstract

Ca(2+) elevation is essential to platelet activation. STIM1 senses Ca(2+) in the endoplasmic reticulum and activates Orai channels allowing store-operated Ca(2+) entry (SOCE). STIM1 has also been reported to be present in the plasma membrane (PM) with its N-terminal region exposed to the outside medium but its role is not fully understood. We have examined the effects of the antibody GOK/STIM1, which recognises the N-terminal region of STIM1, on SOCE, agonist-stimulated Ca(2+) entry, surface exposure, in vitro thrombus formation and aggregation in human platelets. We also determined novel binding partners of STIM1 using proteomics. The dialysed GOK/STIM1 antibody failed to reduced thapsigargin- and agonist-mediated Ca(2+) entry in Fura2-labelled cells. Using flow cytometry we detect a portion of STIM1 to be surface-exposed. The dialysed GOK/STIM1 antibody reduced thrombus formation by whole blood on collagen-coated capillaries under flow and platelet aggregation induced by collagen. In immunoprecipitation experiments followed by proteomic analysis, STIM1 was found to extract a number of proteins including myosin, DOCK10, thrombospondin-1 and actin. These studies suggest that PM STIM1 may facilitate platelet activation by collagen through novel interactions at the plasma membrane while the essential Ca(2+)-sensing role of STIM1 is served by the protein in the ER.

Item Type: Article
Additional Information: Available online 2 December 2013
Research Areas: A. > School of Science and Technology > Natural Sciences
A. > School of Science and Technology > Natural Sciences > Molecular Biology group
Item ID: 19169
Notes on copyright: Open Access funded by Medical Research Council.
Under a Creative Commons license: Creative Commons Attribution License (CC BY) http://creativecommons.org/licenses/by/3.0/
Depositing User: Nick Kassouf
Date Deposited: 11 Apr 2016 11:19
Last Modified: 03 Feb 2021 19:41
URI: https://eprints.mdx.ac.uk/id/eprint/19169

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