Possible involvement of a pertussis toxin-sensitive GTP-binding protein in protein transport into nuclei isolated from rat liver.
Nuclear protein transport was inhibited in permeabilized HeLa cells which had been prepared after culture with pertussis toxin, suggesting that the pertussis toxin-sensitive protein(s) might be involved in the nuclear protein transport. To investigate the mechanism whereby pertussis toxin inhibited the nuclear protein transport, an accumulation of proteins containing a nuclear localization signal sequence (NLS) into isolated rat liver nuclei was investigated. The NLS-containing protein accumulation required ATP and cytosolic proteins, and was temperature- and wheat germ agglutinin-sensitive as had been observed in permeabilized cells. Non-hydrolyzable GTP analogues, such as guanosine 5'-(gamma-thio)triphosphate and guanosine 5'-(beta, gamma-methylene)triphosphate, but not ATP analogues, inhibited the NLS-containing protein accumulation in the isolated nuclei. The NLS-containing protein accumulation was also inhibited by prior treatment of the nuclei with pertussis toxin plus NAD, and the effect of pertussis toxin was blocked when guanosine 5'-(gamma-thio)triphosphate was simultaneously added during the pretreatment with pertussis toxin. The inhibition induced by pertussis toxin and the blockage by guanosine 5'-(gamma-thio)triphosphate were well correlated to ADP-ribosylation of 40-kDa protein in nuclear fraction. These results suggested that the nuclear pertussis toxin-sensitive GTP-binding protein is involved in a pathway of nuclear protein transport.
Takei
Y
Y
Department of Life Science, Tokyo Institute of Technology, Yokohama.
Takahashi
K
K
Kanaho
Y
Y
Katada
T
T
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001692:Biological Transport; D002458:Cell Fractionation; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D004591:Electrophoresis, Polyacrylamide Gel; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006150:Guanine Nucleotides / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D008099:Liver / Q000648:ultrastructure*; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009687:Nuclear Proteins / Q000378:metabolism*; D037342:Pertussis Toxin; D051381:Rats; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D006150:Guanine Nucleotides; D009687:Nuclear Proteins; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins