Store-operated Ca2+ entry in platelets occurs independently of transient receptor potential (TRP) C1

  • David Varga-Szabo
  • Kalwant S. Authi
  • Attila Braun
  • Markus Bender
  • Archana Ambily
  • Sheila R. Hassock
  • Thomas Gudermann
  • Alexander Dietrich
  • Bernhard Nieswandt
Ion Channels, Receptors and Transporters

DOI: 10.1007/s00424-008-0531-4

Cite this article as:
Varga-Szabo, D., Authi, K.S., Braun, A. et al. Pflugers Arch - Eur J Physiol (2008) 457: 377. doi:10.1007/s00424-008-0531-4

Abstract

Changes in [Ca2+]i are a central step in platelet activation. In nonexcitable cells, receptor-mediated depletion of intracellular Ca2+ stores triggers Ca2+ entry through store-operated calcium (SOC) channels. Stromal interaction molecule 1 (STIM1) has been identified as an endoplasmic reticulum (ER)-resident Ca2+ sensor that regulates store-operated calcium entry (SOCE), but the identity of the SOC channel in platelets has been controversially debated. Some investigators proposed transient receptor potential (TRP) C1 to fulfil this function based on the observation that antibodies against the channel impaired SOCE in platelets. However, others could not detect TRPC1 in the plasma membrane of platelets and raised doubts about the specificity of the inhibiting anti-TRPC1 antibodies. To address the role of TRPC1 in SOCE in platelets, we analyzed mice lacking TRPC1. Platelets from these mice display fully intact SOCE and also otherwise unaltered calcium homeostasis compared to wild-type. Furthermore, platelet function in vitro and in vivo is not altered in the absence of TRPC1. Finally, studies on human platelets revealed that the presumably inhibitory anti-TRPC1 antibodies have no specific effect on SOCE and fail to bind to the protein. Together, these results provide evidence that SOCE in platelets is mediated by channels other than TRPC1.

Keywords

Ca2 channelsCa2+-activated channelsIon channelPlateletsThrombin

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • David Varga-Szabo
    • 1
  • Kalwant S. Authi
    • 2
  • Attila Braun
    • 1
  • Markus Bender
    • 1
  • Archana Ambily
    • 2
  • Sheila R. Hassock
    • 2
  • Thomas Gudermann
    • 3
  • Alexander Dietrich
    • 3
  • Bernhard Nieswandt
    • 1
    • 4
  1. 1.Rudolf Virchow Center, DFG Research Center for Experimental BiomedicineUniversity of WürzburgWürzburgGermany
  2. 2.Cardiovascular DivisionKing’s College LondonLondonUK
  3. 3.Department of Pharmacology and ToxicologyPhilipps-Universität MarburgMarburgGermany
  4. 4.Institute of Clinical Biochemistry and PathobiochemistryUniversity of WürzburgWürzburgGermany