title: G(i/o) protein-dependent and -independent actions of Pertussis Toxin (PTX).
abstract: Pertussis toxin (PTX) is a typical A-B toxin. The A-protomer (S1 subunit) exhibits ADP-ribosyltransferase activity. The B-oligomer consists of four subunits (S2 to S5) and binds extracellular molecules that allow the toxin to enter the cells. The A-protomer ADP-ribosylates the α subunits of heterotrimeric G(i/o) proteins, resulting in the receptors being uncoupled from the G(i/o) proteins. The B-oligomer binds proteins expressed on the cell surface, such as Toll-like receptor 4, and activates an intracellular signal transduction cascade. Thus, PTX modifies cellular responses by at least two different signaling pathways; ADP-ribosylation of the Gα(i/o) proteins by the A-protomer (G(i/o) protein-dependent action) and the interaction of the B-oligomer with cell surface proteins (G(i/o) protein-independent action).
authors: Department of Pharmacology, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya, Rajathevi, Bangkok, Thailand. pysmm@mahidol.ac.th
authors: Supachoke
authors: S
authors: Mangmool
authors: Hitoshi
authors: H
authors: Kurose
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics / Q000378:metabolism; D020727:ADP-Ribosylation Factors / Q000235:genetics / Q000378:metabolism; D000818:Animals; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D037342:Pertussis Toxin / Q000737:chemistry* / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D051197:Toll-Like Receptor 4; D036002:ADP Ribose Transferases; D037342:Pertussis Toxin; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020727:ADP-Ribosylation Factors