Answer: adenylyl cyclase inositol triphosphate mainly known as IP3 causes the release of Calcium ions directly from the inracellular stores and causea contraction.
Explanation:
IP3, inositol phosphate is a second messenger a signaling molecule. It is made by hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), a phospholipid that is located in the plasma membrane, by an enzyme phospholipase C.
IP3 binds to the calcium channels and opens Ca2+ channels that are embedded in the ER membrane, releasing Ca2+ into the cytosol. Calcium ions released may cause contraction and regulate the Ca2+ channels in the membranes.
