Regulating expression and function of G-protein-linked receptors.

G-protein-linked receptors constitute a populous family of heptahelical, membrane-localized receptors for hormones, drugs and neurotransmitters that activate a diverse and smaller subset of effectors, including adenylylcyclases, phospholipases and various ion channels. The expression and functional status of G-protein-linked receptors is highly regulated. Expression is controlled largely by activation or repression of the genes encoding the receptors, balanced by post-transcriptional mechanisms such as destabilization of receptor mRNA. Agonist-induced down-regulation of receptors involves both transcriptional and post-transcriptional controls. Gene structure reveals details of promoters as well as determinants for mRNA stability. Post-translational regulation of G-protein-linked receptors is dominated by protein phosphorylation. G-protein-linked receptors are substrates not only for protein kinase A, protein kinase C and receptor-specific kinases, but also for growth factor receptors with intrinsic tyrosine kinase activity. Recent advances in the study of beta-adrenergic receptors (beta ARs) illuminate new dynamic features of receptor regulation, central to our understanding of neurobiology.