Inositol 1,4,5-trisphosphate (IP3) receptors and their role in neuronal cell function

Inositol 1,4,5-trisphosphate (IP3) receptor is a Ca2+ release channel localized on the endoplasmic reticulum (ER) and plays an important role in neuronal function. IP3 receptor was discovered as a developmentally regulated protein missing in the cerebellar mutant mice. Recent studies indicate that IP(3)Rs are involved in early development and neuronal plasticity. IP3 works to release IRBIT from the IP3 binding core in addition to release Ca2+. IRBIT binds to and activates Na, Bicarbonate cotransporter. Electron microscopic study show the IP3 receptor has allosteric property to change its form from square to windmill in the presence of Ca2+. IP3R associates with ERp44, a redox sensor, Homer, other proteins and is transported as vesicular ER on microtubules. All these data suggests IP3 receptor/CA(2+) channel works as a signaling center inside cells.