Impact of phosphodiesterase 4D on cardiac β2 adrenergic receptor signaling

Cyclic adenosine monophosphate (cAMP) is an important intracellular second messenger whose levels are tightly regulated within intracellular subdomains. Generation, detection, and degradation of cAMP is influenced by signaling complexes localized to specific regions of the cell by scaffolding proteins, such as muscle A kinase-anchoring protein (mAKAP). The distribution of cAMP within myocytes differs after β1 adrenergic receptor (β1AR) activation relative to β2AR activation as a result of differences in the interaction of these receptor subtypes with signaling complexes. β1AR stimulation generates a global increase in cAMP, whereas β2AR stimulation elicits a cAMP increase only within restricted areas of the cell. Phosphodiesterase 4D (PDE4D) plays an important role in this process.