The A-kinase anchoring proteins or A-kinase anchor proteins (AKAPs) are a group of structurally diverse proteins, which have the common function of binding to the regulatory subunit of protein kinase A (PKA) and confining the holoenzyme to discrete locations within the cell.
AKAPs act as scaffold proteins wherein they bind PKA and other signaling proteins and physically tether these multi-protein complexes to specific locations, such as the nucleus, in cells.
[2] This allows specific targeting of substrates to be regulated by phosphorylation (by PKA) and dephosphorylation (by phosphatases).
[2] The dimerization and docking (D/D) domain of the regulatory subunit dimer of PKA binds with the A-kinase binding (AKB) domain (an amphipathic helix) of AKAP.
The AKAPs also bind other components, including; phosphodiesterases (PDEs) which break down cAMP, phosphatases which dephosphorylate downstream PKA targets and also other kinases (PKC and MAPK).