Please click here to obtain permission to reproduce this image.
Click on image to view larger version.
Figure 1 Cyclic adenosine monophosphate (cAMP)-mediated signaling in cardiac myocytes. Cyclic adenosine monophosphate generated by adenylate cyclase activates cAMP-dependent protein kinase (PK-A), some of which is in the cytosol and some of which is bound to intracellular membranes by anchoring proteins (AKAPs). Proteins phosphorylated by cAMP-dependent protein kinase include L-type and ryanodine (Ry)-sensitive Ca2+ channels in the sarcolemma and sarcoplasmic reticulum, respectively; phospholamban (PL), which interacts with the Ca2+-transporting adenosine triphosphatase (SERCA2) of the sarcoplasmic reticulum; troponin (Tn) I, complexed with troponin C, troponin T, tropomyosin (TM) and actin in the thin filaments, and transcription factors such as cAMP-response element-binding protein (CREB), whose phosphorylation is dependent upon the translocation of cAMP-dependent protein kinase from the cytosol to the nucleus. ATP = adenosine triphosphate.
|
