During GPCR signaling the activated G protein subunits detaches from the receptor and initiates signaling from many downstream effector proteins such as phospholipases and ion channels, the latter permitting the release of second messenger molecules. The total strength of signal amplification by a GPCR is determined by the lifetimes of the ligand-receptor complex and receptor-effector protein complex and the deactivation time of the activated receptor and effectors through intrinsic enzymatic activity. Signaling pathway effector identifies the second messenger in the signaling cascade (adenylate cyclase, calcium-, potassium-channels, cAMP, PLC, PDE, etc) G alpha q => PLCbeta (PIP2 = IP3 + DAG), PKC, PYK2, MAPK G alpha s => AC (inc cAMP), PKA G alpha i => AC (dec cAMP), MAPK, c-Src to STAT3 and Rap pathways G alpha o => PL and PDE, c-Src to STAT3 and Rap pathways