佛波酯对人肝癌细胞胞液和膜性组分中3类蛋白激酶的早期效应

EARLY EFFECTS OF PHORBOL ESTER ON THE THREE KINDS OF PROTEIN KINASE IN CYTOSOLIC AND MEMBRANOUS FRACTIONS OF HUMAN HEPATOCARCINOMA CELLS

研究佛波酯（PMA）对人肝癌细胞7721胞液和膜性组分中3类蛋白激酶（TPK、PKA、PKC）的早期（5～60min）效应。采用体外细胞培养和蛋白激酶的同位素标记底物测定法。结果：PMA在30min内可促进PKA由膜向胞液的转位和PKC由胞液向膜的转位，并能迅速促进胞液PKC的下降，但膜性PKC的下降发生在30min的活力高峰以后。60min时膜性PKA和PKC都恢复到正常水平。PMA还使胞液TPK持续升高，高峰在5min，而使膜性TPK先降低，40min后才明显升高。结论：PMA对蛋白激酶的早期作用相当多样化，不单是通过受体PKC起作用。

To study the early effects (5-50 min) of phorbol ester on the three protein kinases (TPK,PKA, PKC) in the cytosolic and membranous fractions of 7721 human hepatocellular carcinoma cells.METHODS Cell culture in virto and protein kinase assay with isotope labeled substrate were used.RESULTS It was found that PMA stimulated the translocation of PKA from membrane to cytosol, and translocation of PKC from cytosol to membrane in the first 30 min of PMA treatment. PMA also rapidly decreased the cytosolic PKC, but the decrease of the membranous PKC only appeared after the activity peak at 30 min. Both the activities of membranous and cytosolic PKC recovered to normal level at 60 min. PMA performed a consistant elevation of cytosolic TPK with an activity peak at 5 mon, while membranous TPK showed adecrease first, followed by significant elevation after 40 min.CONCLUSIONS The early effects of PMA on protein kinases are very complicated and not simplely mediated by its receptor PKC.