Fig. 1.

Schematic diagram of general GPCR signaling pathways and key molecular players. Signaling pathways were drawn based on specific functions of four different members of activated Gα and Gβγ complex upon ligand binding. Major effector proteins mediating downstream signaling were also depicted. Acronyms used are as follows. GDP: guanosine diphosphate, GTP: guanosine triphosphate, cAMP: cyclic adenosine monophosphate, PKA: protein kinase A, PLCβ: phospholipase C beta, DAG: diacyl glycerol, IP3: inositol triphosphates, PI3K: phosphoinositide 3-kinase.