Diversity of G Protein-Coupled Receptor Signal Transduction Pathways

1. Diversity of G Protein-Coupled Receptor Signal Transduction Pathways SIGMA-ALDRICH

2. Diversity of G Protein-Coupled Receptor Signal Transduction Pathways Receptors coupled to heterotrimeric GTP-binding proteins (G proteins) are integral transmembrane proteins that transduce extracellular signals to the cell interior. G protein-coupled receptors exhibit a common structural motif consisting of seven membrane spanning regions. Receptor occupation promotes interaction between the receptor and the G protein on the interior surface of the membrane. This induces an exchange of GDP for GTP on the G protein  subunit and dissociation of the  subunit from the  heterodimer. Depending on its isoform, the GTP- subunit complex mediates intracellular signaling either indirectly by acting on effector molecules such as adenylyl cyclase (AC) or phospholipase C (PLC), or directly by regulating ion channel or kinase function. References Schoneberg, T., et al., Structural basis of G protein-coupled receptor function. Mol. Cell. Endocrinol., 151, 181-193 (1999). LeVine, H., 3rd., Structural features of heterotrimeric G protein-coupled receptors and their modulatory proteins. Mol. Neurobiol., 19, 111-149 (1999). Morris, A.J., et al., Physiological regulation of G protein-linked signaling. Physiol. Rev., 79, 1373-1430 (1999).