Abstract
mAKAP (muscle-selective A-kinase-anchoring protein) co-ordinates a cAMP-sensitive negative-feedback loop comprising PKA (cAMP-dependent protein kinase) and the cAMP-selective PDE4D3 (phosphodiesterase 4D3). In vitro and cellular experiments demonstrate that PKA-phosphorylation of PDE4D3 on Ser-13 increases the affinity of PDE4D3 for mAKAP. Our data suggest that activation of mAKAP-anchored PKA enhances the recruitment of PDE4D3, allowing for quicker signal termination.