[KAP2_HUMAN] Regulatory subunit of the cAMP-dependent protein kinases involved in cAMP signaling in cells. Type II regulatory chains mediate membrane association by binding to anchoring proteins, including the MAP2 kinase.
Localization of cyclic AMP (cAMP)-dependent protein kinase (PKA) by A kinase-anchoring proteins (AKAPs) restricts the action of this broad specificity kinase. The high-resolution crystal structures of the docking and dimerization (D/D) domain of the RIIalpha regulatory subunit of PKA both in the apo state and in complex with the high-affinity anchoring peptide AKAP-IS explain the molecular basis for AKAP-regulatory subunit recognition. AKAP-IS folds into an amphipathic alpha helix that engages an essentially preformed shallow groove on the surface of the RII dimer D/D domains. Conserved AKAP aliphatic residues dominate interactions to RII at the predominantly hydrophobic interface, whereas polar residues are important in conferring R subunit isoform specificity. Using a peptide screening approach, we have developed SuperAKAP-IS, a peptide that is 10,000-fold more selective for the RII isoform relative to RI and can be used to assess the impact of PKA isoform-selective anchoring on cAMP-responsive events inside cells.
Molecular basis of AKAP specificity for PKA regulatory subunits.,Gold MG, Lygren B, Dokurno P, Hoshi N, McConnachie G, Tasken K, Carlson CR, Scott JD, Barford D Mol Cell. 2006 Nov 3;24(3):383-95. PMID:17081989
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