Structure-based bacteriophage screening for AKAP-selective PKA regulatory subunit variants.

cAMP-dependent protein kinase (PKA) is tethered at different subcellular locations by A-kinase anchoring proteins (AKAPs). AKAPs present amphipathic helices that bind to the docking and dimerization (D/D) domain of PKA regulatory subunits. Peptide disruptors derived from AKAP anchoring helices are powerful tools for determining whether PKA anchoring is important in different biological processes. Focusing on the reciprocal side of the AKAP-PKA interface can enable development of tools for determining the roles of individual AKAPs. Accordingly, here we describe a bacteriophage screening procedure for identifying variants of PKA regulatory subunit D/D domains that bind selectively to individual AKAPs. This procedure can be adapted for engineering specificity into other shared protein interfaces.