Possible role of Na+ influx in phorbol ester‐induced down‐regulation of protein kinase C in HL60 cells

FEBS Letters

Takeuchi, Fumito¹  Takeuchi, Noriko²  Sada, Kiyonao¹  Yamamura, Hirohei¹  Nakamura, Toru²  Hashimoto, Eikichi¹ 

[1] Departments of Biochemistry, Fukui Medical School, Matsuoka, Fukui, 910-11, Japan;Departments of Internal Medicine, Fukui Medical School, Matsuoka, Fukui, 910-11, Japan

关键词: Protein kinase C;    Down-regulation;    Na+/H+ exchanger;    HL60 cell;    PKC;    protein kinase C;    TPA;    12-O-tetradecanoylphorbol 13-acetate;    SDS-PAGE;    sodium dodecyl sulfate-polyacrylamide gel electrophoresis;    TPBS;    phosphate-buffered saline containing 0.05% Tween 20;   

DOI  :  10.1016/0014-5793(93)80944-P

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Amiloride, an inhibitor of Na⁺/H⁺ exchange, inhibited down-regulation of protein kinase C in HL60 cells induced by tumor-promoting phorbol ester in dose-dependent manner judging from immunoblot analysis. This inhibition was observed with regard to type I (γ), type II (β), and type III (α) isozymes of protein kinase C. On the other hand, monensin, a Na⁺ ionophore, accelerated the down-regulation of protein kinase C induced by phorbol ester. When we examined ²²Na⁺ uptake by HL60 cells, the higher uptake was observed after stimulation with phorbol ester compared to the control cells and this ²²Na⁺ uptake was strongly inhibited by the addition of amiloride. However, monensin further stimulated the ²²Na⁺ uptake observed in phorbol ester-treated cells. These data suggest that the increase in intracellular Na⁺ concentration may be one of the triggers for the induction of down regulation of protein kinase C.

【 授权许可】

Unknown