See Also: GTP-binding protein(medicine)
protein binding(medicine)
DNA binding protein(medicine)
cap binding protein(medicine)
androgen binding protein(medicine)
calcium-binding protein(medicine)
maltose binding protein(medicine)
galactose binding protein(medicine)
vitamin d-binding protein(medicine)
odourant binding protein(medicine)

GTP-binding protein (medicine)


GTP-binding protein
<molecular biology, protein> There are two main classes of G-proteins, the heterotrimeric G proteins that associate with receptors of the seven transmembrane domain superfamily and are involved in signal transduction and the small cytoplasmic G-proteins.

Regulatory proteins found in all cells. They are versatile molecular switches, involved in the control of a wide range of biological processes - protein synthesis, signal transduction pathways, growth and differentiation. They all act through a common molecular mechanism based on their ability to bind the guanine nucleotides GTP and GDP selectively and with high affinity.

Stimulatory G-proteins are permanently activated by cholera toxin, inhibitory ones by pertussis toxin. Transducin was one of the first of the heterotrimeric G-proteins to be identified.

The small G-proteins are a diverse group of monomeric GTPases that include ras, rab, rac and rho and that play an important part in regulating many intracellular processes including cytoskeletal organisation and secretion. Their GTPase activity is regulated by activators (GAPs) and inhibitors (GIPs) that determine the duration of the active state.