Protein kinase A is a cyclic AMP-regulated serine/threonine protein kinase. Binding of cyclic AMP to regulatory subunits relieves inhibition of catalytic subunits, coupling a second messenger to substrate phosphorylation. One downstream target is phosphorylase kinase, linking a hormonal signal to glycogenolysis. Localization and regulatory-subunit composition help specify which substrates respond in a particular cell. [ref]
An adenosine 3′,5′-monophosphate-dependant protein kinase from rabbit skeletal muscle by D. A. Walsh and others. 1968, cyclic nucleotide-dependent kinase activity
New to topics? Read the docs here!