title: Guanine nucleotide binding regulatory proteins: their characteristics and identification.
abstract: Many biological signals are processed by the binding of chemicals to cell surface receptors. Signals are switched to intracellular language via guanine nucleotide binding regulatory proteins (G-proteins) which are present in all eukaryotic cells. Thus, G-proteins serve as interfaces between receptor-response coupling. Two forms of G-proteins have been reported: conventional G-proteins which are heterotrimeric and consist of alpha, beta, and gamma subunits, and monomeric small molecular weight G-proteins which are generally found as single polypeptides. Recently, high molecular weight G-proteins have also been described. The family of G-proteins contains multiple genes that encode the alpha, beta, or gamma subunits. G-proteins play a pivotal role in excitation-contraction coupling in smooth muscle function and control metabolic and secretory processes. In this review article, we have given a brief overview on the characteristics and methodology for the identification of G-proteins. The heterotrimeric G-proteins are generally identified by Western blotting and ADP-ribosylation with bacterial toxins. The monomeric and high molecular weight G-proteins have been identified by [35S]GTP delta S overlay technique and photoaffinity labeling, respectively. Recently, the use of molecular genetic probes has made it possible to investigate the expression of the message for various G-proteins.
authors.affiliation: Department of Internal Medicine, Creighton University School of Medicine, Omaha, Nebraska 68178.
authors.forename: N
authors.initials: N
authors.lastname: Ali
authors.forename: D K
authors.initials: DK
authors.lastname: Agrawal
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D020558:GTP Phosphohydrolases / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D007150:Immunohistochemistry; D009131:Muscle, Smooth, Vascular / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000246:Adenosine Diphosphate Ribose; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins