title: Multiple small molecular weight guanine nucleotide-binding proteins in human erythrocyte membranes.
abstract: Native membranes from human erythrocytes contain the following G proteins which are ADP-ribosylated by a number of bacterial toxins: Gi alpha and Go alpha (pertussis toxin), Gs alpha (cholera toxin), and three proteins of 27, 26 and 22 kDa (exoenzyme C3 from Clostridium botulinum). Three additional C3 substrates (18.5, 16.5 and 14.5 kDa) appeared in conditions of unrestrained proteolysis during hemolysis. SDS-PAGE separation of erythrocyte membrane proteins followed by electroblotting and incubation of nitrocellulose sheets with radiolabeled GTP revealed consistently four GTP-binding proteins with Mr values of 27, 26, 22 and 21 kDa. Although a 22 kDa protein was immunochemically identified as ras p21, the C3 substrate of 22 kDa is a different protein probably identifiable with a rho gene product. Accordingly, at least five distinct small molecular weight guanine nucleotide-binding proteins, whose functions are so far undetermined, are present in native human erythrocyte membranes.
authors.affiliation: Department of Biochemistry, University of Genoa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Damonte
authors.forename: A
authors.initials: A
authors.lastname: Sdraffa
authors.forename: E
authors.initials: E
authors.lastname: Zocchi
authors.forename: L
authors.initials: L
authors.lastname: Guida
authors.forename: C
authors.initials: C
authors.lastname: Polvani
authors.forename: M
authors.initials: M
authors.lastname: Tonetti
authors.forename: U
authors.initials: U
authors.lastname: Benatti
authors.forename: P
authors.initials: P
authors.lastname: Boquet
authors.forename: A
authors.initials: A
authors.lastname: De Flora
mesh_terms: D036002:ADP Ribose Transferases / Q000378:metabolism; D015153:Blotting, Western; D001905:Botulinum Toxins; D002772:Cholera Toxin / Q000378:metabolism; D003014:Clostridium botulinum / Q000201:enzymology; D004910:Erythrocyte Membrane / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000097:blood* / Q000302:isolation & purification; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008970:Molecular Weight; D009243:NAD / Q000097:blood; D037342:Pertussis Toxin; D011485:Protein Binding; D010566:Virulence Factors, Bordetella / Q000378:metabolism
chemical_list: D010566:Virulence Factors, Bordetella; D009243:NAD; D006160:Guanosine Triphosphate; D002772:Cholera Toxin; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D037342:Pertussis Toxin; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins