| Autor: |
Cabot, Myles C., Welsh, Clement J., Zhang, Zu-chuan, Cao, Hui-ting |
| Zdroj: |
FEBS Letters; January 1989, Vol. 245 Issue: 1 p85-90, 6p |
| Abstrakt: |
In this study we provide evidence for the involvement of protein kinase C (PKC) in phorbol diester-induced phosphatidylcholine (PC) hydrolysis by the phospholipase D pathway. Rat embryo fibroblasts (REF52) were prelabeled with either tritiated choline or myristic acid; these compounds are preferentially incorporated into cellular PC. Phorbol diester-induced PC degradation was determined by measuring the release of [ 3H]choline, and the formation of [ 3H]myristoyl-containing phosphatidate (PA), diacylglycerol (DG), and phosphatidylethanol (PE). Staurosporine, a PKC inhibitor, blocked from 73 to 90% of the phorbol diester-induced PC hyrolysis. The inhibition of phorbol diester-induced choline release by staurosporine was dose dependent with an approximate ED 50of 150 nM. Pretreatment of cells with phorbol diester inhibited subsequent phorbol diester-induced PC degradation by 78–92%. A close correlation between the ED 50for phorbol diester-stimulated choline release and the Kdfor phorbol diester binding was demonstrated. Neither forskolin nor dibutyryl cAMP elicited cellular PC degradation. In vitro experiments using phospholipase D from Streptomyces chromofuscusshowed that staurosporine did not inhibit and TPA did not stimulate enzyme activity. |
| Databáze: |
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