Which second messenger is generated from phosphoinositides?

Phosphoinositides play a crucial role in cell signaling, specifically in the generation of second messengers. When phosphoinositides, such as phosphatidylinositol 4,5-bisphosphate (PIP2), are hydrolyzed by the enzyme phospholipase C, they produce two important second messengers: inositol trisphosphate (IP₃) and diacylglycerol (DAG).

IP₃ diffuses into the cytoplasm and binds to receptors on the endoplasmic reticulum, leading to the release of calcium ions into the intracellular space. This calcium signaling is vital for many cellular processes, including muscle contraction and neurotransmitter release.

On the other hand, DAG remains in the membrane and activates protein kinase C (PKC), which is involved in various signaling pathways, including those that regulate cell growth and differentiation.

Thus, the production of both IP₃ and DAG from the metabolism of phosphoinositides solidifies the answer as being correct, as both of these second messengers are integral parts of the signaling cascade initiated by phosphoinositides.