ABSTRACT
The physiological effects of cAMP are virtually all mediated via the action of cytoplasmic cAMP-dependent kinases (protein kinase A, PKA). These protein kinases are tetrameric proteins consisting of two regulatory and two catalytic subunits. Binding of cAMP to the regulatory subunit induces a conformational change and releases the catalytic subunits, allowing them to phosphorylate serine and threonine residues on target proteins, and initiate a series of protein phosphorylation reactions.
