Effector systems

Effector systems for GPCRs: the enzymes adenylyl cyclase, phospholipase C, and guanylate cyclase cause the production of specific second messengers, such as cAMP, IP3, or cGMP, which then mediate intracellular effects. Other effector systems, such as those involving ion channels, are more closely regulated by direct coupling with their G proteins. Effector systems of some GPCRs are unknown.