What is the consequence of IP3 production in cells following PLC activation?

What is the consequence of IP3 production in cells following PLC activation?

• A. Increased intracellular calcium release from stores.
• B. Activation of PKA.
• C. Inhibit second messenger cascades.
• D. Depolarize the membrane directly.

Answer: (A)

When PLC is activated, it cleaves PIP2 into IP3 and DAG. IP3 is water-soluble, so it travels through the cytosol to bind receptors on the endoplasmic reticulum that gate Ca2+ channels. Opening those channels releases Ca2+ from internal stores into the cytosol, raising intracellular calcium levels. That surge in Ca2+ acts as a versatile signal to drive processes like secretion, muscle contraction, and activation of Ca2+-dependent enzymes. DAG stays in the membrane and, together with Ca2+, helps activate PKC, but IP3’s primary action is to release Ca2+ from stores. Activation of PKA requires cAMP, not IP3, and IP3 does not directly depolarize the membrane.

When PLC is activated, it cleaves PIP2 into IP3 and DAG. IP3 is water-soluble, so it travels through the cytosol to bind receptors on the endoplasmic reticulum that gate Ca2+ channels. Opening those channels releases Ca2+ from internal stores into the cytosol, raising intracellular calcium levels. That surge in Ca2+ acts as a versatile signal to drive processes like secretion, muscle contraction, and activation of Ca2+-dependent enzymes. DAG stays in the membrane and, together with Ca2+, helps activate PKC, but IP3’s primary action is to release Ca2+ from stores. Activation of PKA requires cAMP, not IP3, and IP3 does not directly depolarize the membrane.