cAMP-dependent protein kinase (PKA) is a Ser/Thr protein kinase that is highly conserved between species. Three distinct catalytic (C) subunits have been identified, designated C-alpha, C-beta and C-gamma, where C-alpha and C-beta are most closely related. PKA mediates a variety of diverse cellular responses (cell growth and proliferation, ion transport, triglyceride storage and metabolism regulation, embryonic development, and gene transcription) in virtually all eukaryotic systems via phosphorylation of a wide range of downstream target proteins in both they cytoplasm and nucleus.
