Protein kinase A (PKA; EC 2.7.11.11) is one of the numerous members of the cAMP-dependent protein kinase A, -G, and -C (AGC) super family of protein kinases that share structural homology within their catalytic domain and have the similar mechanism of activation[1]. PKA is known to mediate cAMP effects, generated through adenylate cyclase as a response to the activation of G protein-coupled receptors (GPCRs), and can be seen as a central hub that interacts with a variety of other signaling pathways in endocrine cells, not only mediating but also communicating cAMP effects to the mitogen-activated protein kinase (MAPK), protein kinase C and B (PKC and PKB/Akt, respectively)[2].  Protein kinase A phosphorylates substrates in both the cytoplasm and nucleus. The activity of the catalytic (C) subunit is regulated by a set of four different regulatory (R) subunit isoforms. In addition to the regulatory subunits, specificity is also achieved by the scaffold proteins, the A kinase anchoring proteins (AKAPs), which target PKA through the regulatory subunits to different sites within the cell and in close proximity to specific substrates. All of these proteins contribute to the PKA signaling networks that permeate every mammalian cell.

AGC kinases listed: PKA, PKC, PKD