Research Perspective Volume 2, Issue 4 pp 238—243

Figure 1. The PKA pathway. The PKA pathway is a nutrient sensing pathway. In mammals, nutrients are sensed by a G-protein (GEF) that activates an adenylyl cylase (AC). AC produces cAMP, which binds to the regulatory subunits (R) of the PKA holoenzyme, releasing the catalytic subunits (C), which are then free to enter the nucleus of the cell and activate gene transcription or to interact with other signaling proteins in the cell.