The second messenger that causes calcium ion to be released from intracellular stores is
A)Diacylglycerol
B)Adenylyl cyclase
C)Inositol triphosphate
D)Phospholipase A
E)None of the choices are correct

Question

Quizplus · Accepted Answer

Inositol triphosphate (IP3) is the second messenger that causes calcium ion to be released from intracellular stores. When a ligand binds to a G protein-coupled receptor or a receptor tyrosine kinase, it activates a phospholipase C enzyme that hydrolyzes phosphatidylinositol 4,5-bisphosphate (PIP2) into IP3 and diacylglycerol (DAG). IP3 diffuses into the cytoplasm and binds to its receptor on the endoplasmic reticulum, causing the release of calcium ions into the cytoplasm. DAG stays in the membrane and activates protein kinase C (PKC) to phosphorylate target proteins. Adenylyl cyclase, on the other hand, produces cyclic AMP (cAMP), which activates protein kinase A (PKA) and other downstream effectors.

The Second Messenger That Causes Calcium Ion to Be Released