STIM1, an essential and conserved component of store-operated Ca2+ channel function.
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.
Roos
Jack
J
Torrey Pines Therapeutics, Inc., La Jolla, CA 92037, USA.
DiGregorio
Paul J
PJ
Yeromin
Andriy V
AV
Ohlsen
Kari
K
Lioudyno
Maria
M
Zhang
Shenyuan
S
Safrina
Olga
O
Kozak
J Ashot
JA
Wagner
Steven L
SL
Cahalan
Michael D
MD
Veliçelebi
Gönül
G
Stauderman
Kenneth A
KA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D017124:Conserved Sequence / Q000502:physiology; D004330:Drosophila; D029721:Drosophila Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D019143:Evolution, Molecular; D006801:Humans; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D034622:RNA Interference; D000071737:Stromal Interaction Molecule 1; D019284:Thapsigargin / Q000494:pharmacology
D015220:Calcium Channels; D029721:Drosophila Proteins; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D009363:Neoplasm Proteins; C103530:STIM1 protein, human; C502662:Stim protein, Drosophila; D000071737:Stromal Interaction Molecule 1; D019284:Thapsigargin; D002118:Calcium