G protein

(redirected from GTP-binding protein)
Also found in: Encyclopedia.

G protein

A cellular protein activated by the binding of an intercellular signal to its receptor on the cell membrane; the G-protein then activates the enzyme adenyl cyclase within the cell, triggering the formation of cyclic AMP and a stereotyped response.
See also: protein

G protein

a regulatory protein which becomes activated when bound to GTP and is involved in signal transduction.

G protein coupled receptor
a member of a large class of cell-surface signaling receptors that contain seven transmembrane a helices; ligand binding results in activation of a coupled trimeric G protein that then initiates intracellular signal transduction pathways.
References in periodicals archive ?
Abbreviations: NMJ: neuromuscular junction; CNS: central nervous system; mEPSCs: miniature excitatory postsynaptic currents; VGCC: voltage-gated calcium channel; p: release probability; GPCR: GTP-binding protein coupled receptors; PIP2: phosphatidylinositol-4,5-bisphosphate; AP: action potential.
Crystal structure of the GTP-binding protein Obg from Thermus thermophilus HB8.
1991) Identification of two novel GTP-binding protein alpha-subunits that lack apparent ADP-ribosylation sites for pertussis toxin.
coli belong to a group of bacterial toxins that modify Rho, a subfamily of small GTP-binding proteins that are regulators of the actin cytoskeleton (28,29).
Identification of the subunits of GTP-binding proteins coupled to somatostatin receptors.
Guanine nucleotide-sensitive high affinity binding of agonists to purified muscarinic receptors reconstituted with GTP-binding proteins (Gi and Go).
To better understand the link between MIH receptor occupancy and Y-organ cAMP levels, we have assessed the presence of GTP-binding proteins (G-proteins) in Y-organs of the blue crab (Callinectes sapidus).
Despite the dramatic changes induced by EPEC in the cytoskeleton, there appears to be little involvement of the Rho family of small GTP-binding proteins normally involved in cytoskeletal rearrangements (29).
Chadi et a1 (22), reported that compound 48/80 activated mast cell phospholipase D (PLD) via heterotrimeric GTP-binding proteins (22).
In previous studies, we and others have demonstrated that nitric oxide is also important in regulating motility in sea urchin sperm, and we have found further that this process is likely to be dependent on the activity of GTP-binding proteins (11-13).
Small GTP-binding proteins (G-proteins) of the Rho family have been shown to regulate cytoskeleton reorganization, whereas G-proteins of the Rab family have been shown to regulate intracellular trafficking and vesicle transport (1).