A pertussis toxin-sensitive GTP-binding protein plays a role in the G0-G1 transition of rat hepatocytes following establishment in primary culture.
Acute spontaneous c-myc gene expression and sustained increase of a GTP-binding protein(s) (G-protein) which is sensitive to islet-activating protein (IAP), pertussis toxin, occurred early during primary culture of adult rat hepatocytes. Following these earlier events, DNA synthesis was demonstrated in response to EGF and insulin. Addition of IAP immediately after plating of primary cultures inhibited c-myc expression and the hormone-induced DNA synthesis. Addition at 24 h or later following cell inoculation, however, produced only weak effects on DNA synthesis, even though the IAP-sensitive G-proteins were completely inactivated. We conclude that the IAP-sensitive G-protein(s) plays a role in the earlier process(es) of the G0-G1 transition, which is essential for the initiation of growth factor-dependent DNA synthesis.
Fujinaga
Y
Y
Department of Physiological Chemistry, Faculty of Pharmaceutical Science, Hokkaido University, Sapporo, Japan.
Morozumi
N
N
Sato
K
K
Tokumitsu
Y
Y
Fujinaga
K
K
Kondo
Y
Y
Ui
M
M
Okajima
F
F
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004815:Epidermal Growth Factor / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000502:physiology*; D007328:Insulin / Q000494:pharmacology; D007399:Interphase; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008297:Male; D037342:Pertussis Toxin; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D007328:Insulin; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012333:RNA, Messenger; D010566:Virulence Factors, Bordetella; D000246:Adenosine Diphosphate Ribose; D004815:Epidermal Growth Factor; D004247:DNA; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins