Regulation of IP(3) receptors by cyclic AMP

Ca(2+) and cAMP are ubiquitous intracellular messengers and interactions between them are commonplace. Here the effects of cAMP on inositol 1,4,5-trisphosphate receptors (IP(3)Rs) are briefly reviewed. All three subtypes of IP(3)R are phosphorylated by cAMP-dependent protein kinase (PKA). This potentiates IP(3)-evoked Ca(2+) release through IP(3)R1 and IP(3)R2, but probably has little effect on IP(3)R3. In addition, cAMP can directly sensitize all three IP(3)R subtypes to IP(3). The high concentrations of cAMP required for this PKA-independent modulation of IP(3)Rs is delivered to them within signalling junctions that include type 6 adenylyl cyclase and IP(3)R2.