Describe G protein coupled receptors that activate phospholipase C in detail?

G protein-coupled receptors (GPCRs) that activate phospholipase C (PLC) are a type of cell surface receptor that play a crucial role in signal transduction pathways. When these receptors are activated by their ligands, they trigger a series of events that ultimately lead to the activation of PLC.

First, when a ligand binds to the GPCR, it induces a conformational change in the receptor that allows it to interact with a specific G protein. This G protein is a heterotrimeric protein composed of three subunits: alpha, beta, and gamma. Upon binding to the activated receptor, the G protein undergoes a conformational change that causes the alpha subunit to exchange GDP for GTP, leading to its activation.

The activated alpha subunit of the G protein then dissociates from the beta-gamma subunits and interacts with PLC. This interaction activates PLC, which is a membrane-bound enzyme that cleaves phosphatidylinositol 4,5-bisphosphate (PIP2) into two second messengers: inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG).

IP3 diffuses into the cytoplasm and binds to IP3 receptors on the endoplasmic reticulum, leading to the release of calcium ions from intracellular stores. This increase in intracellular calcium levels triggers a variety of downstream signaling events, including the activation of protein kinase C (PKC) by DAG.

PKC phosphorylates a variety of target proteins, leading to changes in cellular function such as gene expression, cell proliferation, and cell differentiation. Overall, the activation of PLC by GPCR signaling plays a critical role in regulating a wide range of physiological processes in the body.