Involvement of Rho p21 small GTP-binding protein and its regulator in the HGF-induced cell motility.
Hepatocyte growth factor (HGF) induced motility of cultured mouse keratinocytes (308R cells). This HGF-induced cell motility was inhibited by microinjection of either rho GDI, an inhibitory GDP/GTP exchange protein for rho p21 small GTP-binding protein, or a botulinum exoenzyme C3 which is known to selectively impair the function of rho p21 by ADP-ribosylating its effector domain. The rho GDI action was prevented by comicroinjection with the guanosine 5'-(3-0-thio)triphosphate (GTP gamma S)-bound active form of rhoA p21, and the C3 action was prevented by comicroinjection with a rhoA p21 mutant (rhoAIle41 p21) which is resistant to the C3 action. The HGF-induced cell motility was not inhibited by microinjection of a dominant negative rac1 p21 mutant (rac1Asn17 p21) or a dominant negative Ki-ras p21 mutant (Ki-rasAsn17 p21). Microinjection of the GTP gamma S-bound form of rac1 p21 or a dominant active Ki-ras p21 mutant (Ki-rasVal12 p21) did not induce cell motility. These results indicate that both rho p21 and rho GDI, but neither rac p21 nor ras p21, are involved in the HGF-induced cell motility. However, microinjection of the GTP gamma S-bound form of rhoA p21 alone did not induce cell motility in the absence of HGF, suggesting that activation of rho p21 is necessary but not sufficient for the HGF-induced cell motility. The HGF-induced cell motility was mimicked by 12-0-tetradecanoyl-phorbol-13-acetate, a protein kinase C-activating phorbol ester, but not by Ca2+ ionophore. The phorbol ester-induced cell motility was also inhibited by microinjection of rho GDI or C3. These results indicate that both rho p21 and rho GDI are also involved in the phorbol ester-induced cell motility.
Takaishi
K
K
Department of Biochemistry, Kobe University School of Medicine, Japan.
Sasaki
T
T
Kato
M
M
Yamochi
W
W
Kuroda
S
S
Nakamura
T
T
Takeichi
M
M
Takai
Y
Y
D036002:ADP Ribose Transferases / Q000502:physiology; D000818:Animals; D001905:Botulinum Toxins; D002465:Cell Movement / Q000187:drug effects; D019204:GTP-Binding Proteins / Q000502:physiology*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D051379:Mice; D008845:Microinjections; D011493:Protein Kinase C / Q000502:physiology; D019859:Proto-Oncogene Proteins c-met; D016283:Proto-Oncogene Proteins p21(ras) / Q000502:physiology; D020794:Receptor Protein-Tyrosine Kinases / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020742:rhoA GTP-Binding Protein
D017228:Hepatocyte Growth Factor; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D019859:Proto-Oncogene Proteins c-met; D020794:Receptor Protein-Tyrosine Kinases; D011493:Protein Kinase C; D001905:Botulinum Toxins; D019204:GTP-Binding Proteins; D016283:Proto-Oncogene Proteins p21(ras); D020742:rhoA GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate