title: Decreased incorporation of the photoaffinity probe 8N3-[gamma-32P]-GTP into a 45kD protein in lung tumors.
abstract: Photoincorporation of 8N3-[gamma-32P]-GTP into tissue and cell extracts was examined using gel electrophoresis and autoradiography. Decreased photoincorporation into a 45kD band was observed in extracts from mouse lung tumors as compared to normal mouse lung, and in extracts from lung tumor-derived cell lines when compared to isolated bronchiolar epithelial cells. Decreased 45kD photolabelling was also observed in extracts of S49 lymphoma cyc- cells (deficient in Gs alpha, a 45kD GTP binding protein of receptor-coupled adenylate cyclase) when compared to wild type S49 cells. This, and the observation that there was no cholera toxin-catalyzed ADP-ribosylation in the 45kD band of lung tumor extracts, suggests that the 45kD band contains Gs alpha.
mesh_terms: D000345:Affinity Labels; D000818:Animals; D001386:Azides / Q000378:metabolism*; D002460:Cell Line; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives* / Q000378:metabolism; D008168:Lung / Q000378:metabolism*; D008175:Lung Neoplasms / Q000378:metabolism*; D051379:Mice; D008805:Mice, Inbred A; D008970:Molecular Weight; D009363:Neoplasm Proteins / Q000096:biosynthesis*; D010761:Phosphorus Radioisotopes; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: C021961:8-azidoguanosine triphosphate; D000345:Affinity Labels; D001386:Azides; D009363:Neoplasm Proteins; D010761:Phosphorus Radioisotopes; D006160:Guanosine Triphosphate