Inositol phospholipid signalling pathway

 The Insitol signallng pathway is activated when a signal molecule binds to he receptor of a trimeric G protein. The binding of the signal molecule casues the GDP bound to the G protein to exchanged for GTP, this induces a conformational change and the alpha subunit dissociates itself from the beta and gamma subuits. The alpha subunit then activates phospholipase C. The phospholipase c then cleaves phosphoinositol 4,5- biphosphate (PIP₂); producing Diacylglycerol (DAG) and Inositol 1,4,5 triphosphate (IP₃). DAG remains embedded in the phospholipid membrane, where as IP₃ moves into the cytoplasm. IP₃ then binds to IP₃ gated Ca²⁺ release channels on the membrane of the endoplsamic reticulum, this inturn releases Ca^₂₊ ions, which binds to Protein Kinase C (PKC). The DAG also binds to PKC, which consequently activates the Protein Kinase C. The PKC then phosphorylates  various proteins in order to amplify the signal.