STIM, ORAI and TRPC channels in the control of calcium entry signals in smooth muscle

Youjun Wang, Xiaoxiang Deng, Thamara Hewavitharana, Jonathan Soboloff, Donald L. Gill

Research output: Contribution to journalArticlepeer-review

93 Scopus citations


1. Ca2+ entry signals are crucial in the control of smooth muscle contraction. Smooth muscle cells are unusual in containing plasma membrane (PM) Ca2+ entry channels that respond to voltage changes, receptor activation and Ca2+ store depletion. 2. Activation of these channel subtypes is highly coordinated. The TRPC6 channel, widely expressed in most smooth muscle cell types, is largely non-selective to cations and is activated by diacylglycerol arising from receptor-induced phosholipase C activation. 3. Receptor activation results largely in Na+ ion movement through TRPC6 channels, depolarization and subsequent activation of voltage-dependent L-type Ca2+ channels. The TRPC6 channels also appear to be activated by mechanical stretch, resulting again in depolarization and L-type Ca2+ channel activation. Such a coupling may be crucial in mediating the myogenic tone response in vascular smooth muscle. 4. The emptying of stores mediated by inositol 1,4,5-trisphosphate receptors triggers the endoplasmic reticulum (ER) Ca2+ sensing protein stromal-interacting molecule (STIM) 1 to translocate into defined ER-PM junctional areas in which coupling occurs to Orai proteins, which serve as highly Ca2+- selective low-conductance Ca2+ entry channels. 5. These ER-PM junctional domains may serve as crucial sites of interaction and integration between the function of store-operated, receptor-operated and voltage-operated Ca2+ channels. The STIM, Orai and TRPC channels represent highly promising new pharmacological targets through which such control may be induced.

Original languageEnglish (US)
Pages (from-to)1127-1133
Number of pages7
JournalClinical and Experimental Pharmacology and Physiology
Issue number9
StatePublished - Sep 2008

All Science Journal Classification (ASJC) codes

  • Physiology
  • Pharmacology
  • Physiology (medical)


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