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Signal Transduction
Universal
cAMP/PKA Signaling
Cyclic AMP as a second messenger activating protein kinase A.
Overview
Adenylyl cyclase converts ATP to cAMP in response to Gαs-coupled GPCR activation. cAMP binds the regulatory subunits of PKA, releasing catalytic subunits that phosphorylate target proteins including CREB transcription factor, ion channels, and metabolic enzymes. Phosphodiesterases (PDEs) terminate signaling by degrading cAMP. This pathway regulates glycogen metabolism, lipolysis, cardiac function, and gene expression.
Cellular Location
Cytoplasm → Nucleus
Clinical Significance
One of the first discovered second messenger systems (Sutherland, Nobel 1971); PDE inhibitors treat COPD (roflumilast), erectile dysfunction (sildenafil), and heart failure (milrinone).