- 作者: Lan Chun Tu Chen-Kung Chou Hua-Chien Chen Sheau-Farn Yeh
- 作者服務機構: Institule of Biochemisty, National Yang-Ming University; Depatment of Medical Research, Vetorans General Hospital, and Division of Molecular and Genomic Medicine, National Health Research Institutes, Nan-Kan, Taipei, Taiwan, ROC
- 中文摘要: --
- 英文摘要: Treatment of cultured human hepatoma HepG2 cellswith the protein kinase C (PKC) activator, 12-O-tetradeca-noylphorbol-13-acetate (TPA), results in an increase intyrosine phosphorylation of several proteins, includingthe focal adhesion kinase (FAK) and paxillin using anti-phosphotyrosine Western blotting and immunoprecipi-tation. However, when cells are in suspension or in thepresence of cytochalasin D which disrupts the intracellu-lar network of actin microfilaments, TPA loses its abilityto stimulate tyrosine phosphorylation of FAK and paxillinbut it still activates mitogen-activated protein kinase(MAPK) and induces PKC translocation from cytosol tothe membrane in HepG2 cells. On the other hand,PD98059, a specific inhibitor of mitogen-activated pro-tein kinase kinase, blocks TPA-induced MAPK activationbut has no effect on TPA-induced tyrosine phosphoryla-tion. Our findings suggest that TPA-induced tyrosinephosphorylation of FAK and paxillin in human hepatomacells is PKC dependent and requires the integrity of thecell cytoskeleton but is uncoupled to the signal transduc-tion pathway of PKC leading to the translocation of PKCand MAPK activation.
- 中文關鍵字: --
- 英文關鍵字: Cytoskeleton integrity. Human hepatoma cells. MAP kinase. Protein kinase C. Tyrosine phosphorylation