Functional and structural complexity of signal transduction via G-protein-coupled receptors.
A prerequisite for the maintenance of homeostasis in a living organism is fine-tuned communication between different cells. The majority of extracellular signaling molecules, such as hormones and neurotransmitters, interact with a three-protein transmembrane signaling system consisting of a receptor, a G protein, and an effector. These single components interact sequentially and reversibly. Considering that hundreds of G-protein-coupled receptors interact with a limited repertoire of G proteins, the question of coupling specificity is worth considering. G-protein-mediated signal transduction is a complex signaling network with diverging and converging transduction steps at each coupling interface. The recent realization that classical signaling pathways are intimately intertwined with growth-factor-signaling cascades adds another level of complexity. Elaborate studies have significantly enhanced our knowledge of the functional anatomy of G-protein-coupled receptors, and the concept has emerged that receptor function can be modulated with high specificity by coexpressed receptor fragments. These results may have significant clinical impact in the future.
Gudermann
T
T
Institut für Pharmakologie, Freie Universität Berlin, Germany.
Schöneberg
T
T
Schultz
G
G
D000818:Animals; D019204:GTP-Binding Proteins / Q000502:physiology*; D011984:Sensory Receptor Cells / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
D019204:GTP-Binding Proteins