fig1

Figure 1. The signaling cascade initiated upon agonist binding to a G protein-coupled transmembrane receptor (GPCR). The exchange of GDP by GTP causes a dissociation of the Gα subunit from the βγ subunit. The activated alpha subunit can alter downstream effectors. Each of the alpha subunits has a specific set of second messengers, while the dissociated βγ subunit can independently activate a variety of effectors