Identification of a guanine nucleotide-binding protein G(o) in human neuroblastoma.
It has been found that neuroblastoma contains a relatively high immunoreactivity for the alpha subunit of guanine nucleotide-binding protein G(o) (G(o) alpha) (Kato et al., Cancer Res. 47, 5800-5805, 1987), which is predominantly localized in the nervous tissues and neuroendocrine cells. To make clear whether neuroblastoma indeed produces G(o) alpha, we purified a guanine nucleotide-binding protein from human neuroblastoma and compared it with G(o) alpha from human brain. A guanine nucleotide-binding protein serving as the specific substrate of islet-activating protein, pertussis toxin, was purified from a human neuroblastoma tissue obtained at surgical resection. The protein had a molecular mass of 39 kDa and reacted with rabbit antibodies to bovine G(o) alpha. Heat stability and kinetics of guanosine 5'-(3-O-thio)triphosphate binding of this protein were very similar to those of G(o) alpha purified from human brain. The results of peptide mapping analysis with a limited proteolysis and amino acid analysis indicated that there was no difference between these proteins. Therefore, it was concluded that this guanine nucleotide-binding protein isolated from neuroblastoma was very similar, if not identical, to brain G(o) alpha.
D000596:Amino Acids / Q000032:analysis; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000276:immunology / Q000302:isolation & purification*; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D009447:Neuroblastoma / Q000032:analysis*; D013873:Thionucleotides / Q000378:metabolism
D000596:Amino Acids; D013873:Thionucleotides; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins