Targets the cAMP-dependent protein kinase (PKA) to the plasma membrane, and permits functional coupling to the L-type calcium channel. The membrane-associated form reduces epithelial sodium channel (ENaC) activity, whereas the free cytoplasmic form may negatively regulate ENaC channel feedback inhibition by intracellular sodium. Binds cAMP-dependent protein kinase (PKA). Interacts with PRKCA; only the cytoplasmic form is capable of interacting with PRKCA. Targeted predominantly to the lateral membrane. Targeted predominantly to the apical membrane. Additional isoforms seem to exist. Expressed in brain, heart, lung, pancreas and skeletal muscle.