Phospholipids are hydrolyzed into which second messenger, notably involved in calcium signaling?

The correct answer is in fact associated with the process of phospholipid hydrolysis, particularly phosphatidylinositol 4,5-bisphosphate (PIP2), which is cleaved by phospholipase C to produce inositol trisphosphate (IP3) and diacylglycerol (DAG). IP3 plays a crucial role as a second messenger in calcium signaling pathways.

When IP3 is generated, it diffuses through the cytosol and binds to IP3 receptors on the endoplasmic reticulum, leading to the release of calcium ions into the cytoplasm. This increase in intracellular calcium is essential for various cellular processes, including muscle contraction, neurotransmitter release, and other signaling cascades.

DAG, although produced concurrently, primarily activates protein kinase C (PKC) and is not as directly involved in calcium signaling compared to IP3. cAMP, another second messenger, is involved in different signaling pathways, primarily related to hormonal responses and energy metabolism, while GTP is a nucleotide involved in intracellular signaling and energy transfer but not specifically a second messenger derived from phospholipid hydrolysis. Thus, IP3 is the most relevant second messenger arising from the hydrolysis of phospholipids