Guanosine triphosphate , signal transduction

G proteins comprise several families of diverse cellular proteins that subserve an equally diverse array of cellular functions. These proteins derive their name from the fact that they bind the guanine nucleotides guanosine triphosphate (GTP) and guanosine diphosphate (GDP) and possess intrinsic GTPase activity. G proteins play a central role in signal transduction as well as in a myriad of cellular processes, including membrane vesicle transport,... 

All GTP binding proteins in signal transduction share a common structural element - the Ras-like domain which is responsible for the specific complexation of guanosine diphosphate and -triphosphate and which contains catalytic residues that promote GTP-hydrolysis. 

The presence of a nitrogen-containing side chain facilitates interaction with the catalytic site of FPPS, an enzyme in the metabolic pathway that is required for the production of the isoprenoid hpids farnesyl diphosphate and geranylgeranyl diphosphate, essential metabolites for posttranslational protein prenylation [5, 8]. Inhibiting the prenylation of guanosine triphosphate-binding proteins such as Ras, Rho, and Rac disrupts the normal cellular signal transduction that is required for osteoclast function and survival [5]. 

G TP-guanosine 5 -triphosphate An important molecule in signal transduction as it forms cGMP, an important second messenger. 

Receptor-mediated, guanosine 5 -triphosphate (GTP) protein-dependent signal transduction, initiated by stimulation of cholinergic M, receptors or dopaminergic D2 receptors, can activate PLAi to release arachidonate and/or docosahexaenoate from the sn-2 position of phospholipids (Axelrod et al., 1988 DeGeorge et al., 1991 Jones, Aral, Bell, Rapoport, 1996 Jones, Aral, Rapoport, 1997). This is illustrated for arachidonate in Fig. 4, which also shows that unlabeled arachidonic acid that is liberated by PI. A, into the brain unesterified pool can be rapidly labeled by tracer arachidonate injected into plasma (Grange et al., 1995 Washizaki et al., 1994). A fraction of the unesterified... 

G protein A guanosine triphosphate (GTP)-binding protein that serves as a transducer in a signal transduction pathway. On binding GTP and releasing guanosine diphosphate (GDP), a G protein is able to activate the effector enzyme (e.g., adenylate cyclase). 

GTP Guanosine triphosphate, a nucleotide serving as a switch in many important processes including protein biosynthesis and signal transduction. 

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