Phospholipase-catalyzed hydrolysis of which of the following compounds results in an increased cytosolic concentration of calcium ions in response to ligand binding to members of serotonin receptor family?
A) phosphatidylcholine
B) phosphatidylethanolamine
C) phosphatidylgylcerol
D) phosphatidylinositol bisphosphate
E) phosphatidylserine

Question

Quizplus · Accepted Answer

Phospholipase C hydrolyzes phosphatidylinositol bisphosphate (PIP2) to produce inositol trisphosphate (IP3), which then triggers the release of calcium ions from the endoplasmic reticulum into the cytosol. Several members of the serotonin receptor family are coupled to the G_q class of G-proteins that activate membrane-associated PLC-β. Active PLC-β hydrolyzes membrane-associated phosphatidylinositol- 4,5-bisphosphate, PIP₂), resulting in increased production of the intracellular messengers IP₃ and DAG. IP₃ binds to a receptor on the ER membrane and triggers the release of stored calcium ion into the cytosol. The calcium ions and the DAG serve to act as second messengers in the activation of PKC.

Phospholipase-Catalyzed Hydrolysis of Which of the Following Compounds Results in an Increased