Polycystin-2 activation by inositol 1,4,5-trisphosphate-induced Ca2+ release requires its direct association with the inositol 1,4,5-trisphosphate receptor in a signaling microdomain

J Biol Chem. 2010 Jun 11;285(24):18794-805. doi: 10.1074/jbc.M109.090662. Epub 2010 Apr 7.


Autosomal dominant polycystic kidney disease is characterized by the loss-of-function of a signaling complex involving polycystin-1 and polycystin-2 (TRPP2, an ion channel of the TRP superfamily), resulting in a disturbance in intracellular Ca(2+) signaling. Here, we identified the molecular determinants of the interaction between TRPP2 and the inositol 1,4,5-trisphosphate receptor (IP(3)R), an intracellular Ca(2+) channel in the endoplasmic reticulum. Glutathione S-transferase pulldown experiments combined with mutational analysis led to the identification of an acidic cluster in the C-terminal cytoplasmic tail of TRPP2 and a cluster of positively charged residues in the N-terminal ligand-binding domain of the IP(3)R as directly responsible for the interaction. To investigate the functional relevance of TRPP2 in the endoplasmic reticulum, we re-introduced the protein in TRPP2(-/-) mouse renal epithelial cells using an adenoviral expression system. The presence of TRPP2 resulted in an increased agonist-induced intracellular Ca(2+) release in intact cells and IP(3)-induced Ca(2+) release in permeabilized cells. Using pathological mutants of TRPP2, R740X and D509V, and competing peptides, we demonstrated that TRPP2 amplified the Ca(2+) signal by a local Ca(2+)-induced Ca(2+)-release mechanism, which only occurred in the presence of the TRPP2-IP(3)R interaction, and not via altered IP(3)R channel activity. Moreover, our results indicate that this interaction was instrumental in the formation of Ca(2+) microdomains necessary for initiating Ca(2+)-induced Ca(2+) release. The data strongly suggest that defects in this mechanism may account for the altered Ca(2+) signaling associated with pathological TRPP2 mutations and therefore contribute to the development of autosomal dominant polycystic kidney disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoviridae / metabolism
  • Animals
  • Calcium / metabolism*
  • DNA / metabolism
  • Endoplasmic Reticulum / metabolism
  • Epithelial Cells / metabolism
  • Glutathione Transferase / metabolism
  • Inositol 1,4,5-Trisphosphate / chemistry*
  • Inositol 1,4,5-Trisphosphate Receptors / chemistry*
  • Inositol 1,4,5-Trisphosphate Receptors / metabolism
  • Kidney / metabolism
  • Mice
  • Mutation
  • Protein Structure, Tertiary
  • Signal Transduction
  • TRPP Cation Channels / metabolism*


  • Inositol 1,4,5-Trisphosphate Receptors
  • TRPP Cation Channels
  • polycystic kidney disease 2 protein
  • Inositol 1,4,5-Trisphosphate
  • DNA
  • Glutathione Transferase
  • Calcium