Calmodulin regulates Ca2+-dependent feedback inhibition of store-operated Ca2+ influx by interaction with a site in the C terminus of TrpC1

Brij B. Singh, Xibao Liu, Jisen Tang, Michael X. Zhu, Indu S. Ambudkar

Research output: Contribution to journalArticlepeer-review

119 Scopus citations


The mechanism involved in [Ca2+]i-dependent feedback inhibition of store-operated Ca2+ entry (SOCE) is not yet known. Expression of Ca2+-insensitive calmodulin (Mut-CaM) but not wild-type CaM increased SOCE and decreased its Ca2+-dependent inactivation. Expression of TrpC1 lacking C terminus aa 664-793 (TrpC1ΔC) also attenuated Ca2+-dependent inactivation of SOCE. CaM interacted with endogenous and expressed TrpC1 and with GST-TrpC1 C terminus but not with TrpC1ΔC. Two CaM binding domains, aa 715-749 and aa 758-793, were identified. Expression of TrpC1Δ758-793 but not TrpC1Δ715-749 mimicked the effects of TrpC1ΔC and Mut-CaM on SOCE. These data demonstrate that CaM mediates Ca2+-dependent feedback inhibition of SOCE via binding to a domain in the C terminus of TrpC1. These findings reveal an integral role for TrpC1 in the regulation of SOCE.

Original languageEnglish (US)
Pages (from-to)739-750
Number of pages12
JournalMolecular Cell
Issue number4
StatePublished - 2002
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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