Alan Smrcka, Ph.D.

G protein coupled receptors (GPCRs) form a large family of cell surface receptors responsible for triggering cellular responses to a variety of extracellular stimuli including drugs such as opiates, and hormones such as adrenaline, serotonin or acetylcholine. All GPCRs function through activation of trimeric G proteins located on the inner surface of the plasma membrane. Activated G proteins target ion channels or enzymes that produce second messengers with a variety of effects depending on the type of cell that is stimulated. Examples include regulation of synaptic transmission in the central nervous system, chemotaxis in the immune system, and vascular remodeling in the cardiovascular system. This family of receptors is an important target for pharmaceuticals and defects in GPCR systems are responsible for a number of diseases.