TRPC3 controls agonist-stimulated intracellular Ca2+ release by mediating the interaction between inositol 1,4,5-trisphosphate receptor and RACK1

J Biol Chem. 2008 Nov 21;283(47):32821-30. doi: 10.1074/jbc.M805382200. Epub 2008 Aug 28.

Abstract

Activation of TRPC3 channels is concurrent with inositol 1,4,5-trisphosphate (IP(3)) receptor (IP(3)R)-mediated intracellular Ca(2+) release and associated with phosphatidylinositol 4,5-bisphosphate hydrolysis and recruitment to the plasma membrane. Here we report that interaction of TRPC3 with receptor for activated C-kinase-1 (RACK1) not only determines plasma membrane localization of the channel but also the interaction of IP(3)R with RACK1 and IP(3)-dependent intracellular Ca(2+) release. We show that TRPC3 interacts with RACK1 via N-terminal residues Glu-232, Asp-233, Glu-240, and Glu-244. Carbachol (CCh) stimulation of HEK293 cells expressing wild type TRPC3 induced recruitment of a ternary TRPC3-RACK1-IP(3)R complex and increased surface expression of TRPC3 and Ca(2+) entry. Mutation of the putative RACK1 binding sequence in TRPC3 disrupted plasma membrane localization of the channel. CCh-stimulated recruitment of TRPC3-RACK1-IP(3)R complex as well as increased surface expression of TRPC3 and receptor-operated Ca(2+) entry were also attenuated. Importantly, CCh-induced intracellular Ca(2+) release was significantly reduced as was RACK1-IP(3)R association without any change in thapsigargin-stimulated Ca(2+) release and entry. Knockdown of endogenous TRPC3 also decreased RACK1-IP(3)R association and decreased CCh-stimulated Ca(2+) entry. Furthermore, an oscillatory pattern of CCh-stimulated intracellular Ca(2+) release was seen in these cells compared with the more sustained pattern seen in control cells. Similar oscillatory pattern of Ca(2+) release was seen after CCh stimulation of cells expressing the TRPC3 mutant. Together these data demonstrate a novel role for TRPC3 in regulation of IP(3)R function. We suggest TRPC3 controls agonist-stimulated intracellular Ca(2+) release by mediating interaction between IP(3)R and RACK1.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amino Acid Sequence
  • Biotinylation
  • Calcium / chemistry
  • Calcium / metabolism*
  • Electrophysiology
  • GTP-Binding Proteins / chemistry*
  • Humans
  • Inositol 1,4,5-Trisphosphate Receptors / chemistry*
  • Microscopy, Confocal
  • Models, Biological
  • Molecular Sequence Data
  • Mutation
  • Neoplasm Proteins / chemistry*
  • Oscillometry
  • Protein Binding
  • Receptors for Activated C Kinase
  • Receptors, Cell Surface / chemistry*
  • TRPC Cation Channels / metabolism*
  • Two-Hybrid System Techniques

Substances

  • Inositol 1,4,5-Trisphosphate Receptors
  • Neoplasm Proteins
  • RACK1 protein, human
  • Receptors for Activated C Kinase
  • Receptors, Cell Surface
  • TRPC Cation Channels
  • TRPC3 cation channel
  • GTP-Binding Proteins
  • Calcium