The targets of cAMP include:
- cAMP-dependent protein kinase (PKA).
- Cyclic nucleotide gated ion channels.
- Guanine exchanging factors Epac1 and Epac2 that regulate the activity of Rap1.
PKA is its principal target.
Figure 6-F-1. A cAMP/PKA signaling
pathway. PKA consists of two catalytic
subunits and two regulatory subunits. cAMP
binds to two sites on each regulatory subunit. Binding of four cAMP molecules
causes the release of free and active catalytic subunits, which may phosphorylate serine and threonine residues on
target proteins. In this figure, the active subunit phosphorylates a CREB protein, resulting in transcription.