conformation change & activation of G protein --> exchange of GDP for GTP and dissociation between a- and 13 y subunits which interact with effectors. a - subunit act on Na, Ca, K- channels and phospholipse - C (PLC). p y subunit acts on adenyl cyclase, phospholipase A2, DLC, Ca - ATPase etc. Adenyl cyclase - cAMP pathway activation (i.e. adenyl cyclase activation lit T cAMP) causes stimulatin of cAMP dependent pein kinase (protein kinase A) which phosphorylates the receptorQ. G protein coupled receptor kinase are protein kinase that phosphorylates only active GPCRs Phosphorylation of receptor 1/t translocation & arrest linking. GPCRs are found only in eukaryotes, including yeast, plants & choanoflagellates. These are grouped in 6 classes: A (rhodopsin like); B (secretin receptor family); C (pheromone/ metabotropic glutamate); D (Fungal mating pheromone receptor); E (cyclic AMP receptor); and F (frizzled or smoothened).">