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

Ambily, A. and Kaiser, W. J. and Pierro, C. and Chamberlain, E. V. and Li, Z. and Jones, C. I. and Kassouf, Nick and 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

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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: 07 Sep 2018 21:09
URI: http://eprints.mdx.ac.uk/id/eprint/19169

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