During signal transduction, one molecule of phosphatidylinositol 4,5-bisphosphate (PIP2) is cleaved into one molecule each of inositol triphosphate…
During signal transduction, one molecule of phosphatidylinositol 4,5-bisphosphate (PIP2) is cleaved into one molecule each of inositol triphosphate (IP3) and diacylglycerol (DAG) by the enzyme:
Select an option to attempt
Correct Answer: Option D
Explanation
Phospholipase C (PLC) and PIP2 cleavage in signal transduction:In the IP3/DAG signalling pathway:1. A ligand (e.g., hormone) binds its receptor → activates a G-protein (Gq) or RTK → activates Phospholipase C-β (or PLC-γ).2. PLC cleaves PIP2 (phosphatidylinositol 4,5-bisphosphate) at the phosphodiester bond:3. IP3 (inositol 1,4,5-trisphosphate): diffuses to the ER, opens IP3R Ca²⁺ channels → calcium release → activates calmodulin-dependent kinases.4. DAG (diacylglycerol): stays in the membrane → activates Protein Kinase C (PKC) → phosphorylates downstream targets.The enzyme is Phospholipase C (not Lipolyase, Phosphatase, or Phosphodiesterase C — none of these are real enzyme names for this reaction).Answer: Phospholipase C (Option 4).