STIM1, an essential and conserved component of store-operated Ca2+ channel function

J Cell Biol. 2005 May 9;169(3):435-45. doi: 10.1083/jcb.200502019. Epub 2005 May 2.

Abstract

Store-operated Ca2+ (SOC) channels regulate many cellular processes, but the underlying molecular components are not well defined. Using an RNA interference (RNAi)-based screen to identify genes that alter thapsigargin (TG)-dependent Ca2+ entry, we discovered a required and conserved role of Stim in SOC influx. RNAi-mediated knockdown of Stim in Drosophila S2 cells significantly reduced TG-dependent Ca2+ entry. Patch-clamp recording revealed nearly complete suppression of the Drosophila Ca2+ release-activated Ca2+ (CRAC) current that has biophysical characteristics similar to CRAC current in human T cells. Similarly, knockdown of the human homologue STIM1 significantly reduced CRAC channel activity in Jurkat T cells. RNAi-mediated knockdown of STIM1 inhibited TG- or agonist-dependent Ca2+ entry in HEK293 or SH-SY5Y cells. Conversely, overexpression of STIM1 in HEK293 cells modestly enhanced TG-induced Ca2+ entry. We propose that STIM1, a ubiquitously expressed protein that is conserved from Drosophila to mammalian cells, plays an essential role in SOC influx and may be a common component of SOC and CRAC channels.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Calcium / metabolism*
  • Calcium Channels / metabolism*
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • Cell Line
  • Cell Membrane / metabolism*
  • Conserved Sequence / physiology
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / isolation & purification
  • Drosophila Proteins / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Evolution, Molecular
  • Humans
  • Jurkat Cells
  • Membrane Proteins / genetics
  • Membrane Proteins / isolation & purification
  • Membrane Proteins / metabolism*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Patch-Clamp Techniques
  • RNA Interference
  • Stromal Interaction Molecule 1
  • Thapsigargin / pharmacology

Substances

  • Calcium Channels
  • Drosophila Proteins
  • Enzyme Inhibitors
  • Membrane Proteins
  • Neoplasm Proteins
  • STIM1 protein, human
  • Stim protein, Drosophila
  • Stromal Interaction Molecule 1
  • Thapsigargin
  • Calcium