Stabilization of Cortical Actin Induces Internalization of Transient Receptor Potential 3 (Trp3)-associated Caveolar Ca2+ Signaling Complex and Loss of Ca2+ Influx without Disruption of Trp3-Inositol Trisphosphate Receptor Association

Timothy Lockwich, Brij B. Singh, Xibao Liu, Indu S. Ambudkar

Research output: Contribution to journalArticle

131 Scopus citations


Ca2+ influx via plasma membrane Trp3 channels is proposed to be regulated by a reversible interaction with inositol trisphosphate receptor (IP3R) in the endoplasmic reticulum. Condensation of the cortical actin layer has been suggested to physically disrupt this interaction and inhibit Trp3-mediated Ca2+ influx. This study examines the effect of cytoskeletal reorganization on the localization and function of Trp3 and key Ca2+ signaling proteins. Calyculin-A treatment resulted in formation of condensed actin layer at the plasma membrane; internalization of Trp3, Gαq/11, phospholipase Cβ, and caveolin-1; and attenuation of 1-oleoyl-2-acetyl-sn-glycerol- and ATP-stimulated Sr2+ influx. Importantly, Trp3 and IP3R-3 remained co-localized inside the cell and were co-immunoprecipitated. Jasplakinolide also induced internalization of Trp3 and caveolin-1. Pretreatment of cells with cytochalasin D or staurosporine did not affect Trp3 but prevented calyculin-A-induced effects. Based on these data, we suggest that Trp3 is assembled in a caveolar Ca2+ signaling complex with IP3R, SERCA, Gαq/11, phospholipase Cβ, caveolin-1, and ezrin. Furthermore, our data demonstrate that conditions which stabilize cortical actin induce loss of Trp3 activity due to internalization of the Trp3-signaling complex, not disruption of IP 3R-Trp3 interaction. This suggests that localization of the Trp3-associated signaling complex, rather than Trp3-IP3R coupling, depends on the status of the actin cytoskeleton.

Original languageEnglish (US)
Pages (from-to)42401-42408
Number of pages8
JournalJournal of Biological Chemistry
Issue number45
StatePublished - Nov 9 2001
Externally publishedYes


ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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