PMA and staurosporine affect expression of the PCK gene in LLC-PK1-F+ cells.
PMA and staurosporine affect expression of the PCK gene in LLC-PK1-F+ cells.
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PMA 和 staurosporine 影响 LLC-PK1-F 细胞中 PCK 基因的表达。
DOI：
10.1152/ajprenal.1998.275.3.f361
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
Curthoys,NP
中科院分区：
文献类型：
--
作者：
Liu,W;Feifel,E;Holcomb,T;Liu,X;Spitaler,N;Gstraunthaler,G;Curthoys,NP
在肾lc - pk1 - f +细胞中添加磷酸烯醇丙酮酸羧激酶（PCK） mRNA水平迅速下降，并逆转了暴露于酸性培养基（pH 6.9, 10 mM）或cAMP的刺激作用。相反，PMA的长期治疗增加了PCK mRNA的水平。这两种效应与蛋白激酶C的膜易位和α-同工酶的下调相关，并被特异性蛋白激酶C抑制剂预处理阻断。PMA引起的PCK mRNA的快速下降发生在半衰期（t½= 1 h），明显快于从酸性培养基中恢复或转录抑制（t½= 4 h）。staurosporine通过抑制蛋白激酶c以外的信号通路来逆转PMA的作用，staurosporine对PCK mRNA的半衰期没有影响，但它刺激了一个氯霉素乙酰转移酶基因的活性，该基因由PCK启动子的490个碱基对驱动，并瞬间转染到LLC-PK1-F+细胞中。这种作用与cAMP的作用是叠加的，并且两种刺激都不能被PMA逆转。staurosporine的刺激作用定位于PCK启动子的cAMP应答元件（CRE-1）和P3（II）元件。这些数据表明，在LLC-PK1-F+细胞中，蛋白激酶C的激活降低了PCK mRNA的稳定性，而PCK基因的转录可能被一种被staurosporine抑制的激酶所抑制。
The addition of phorbol 12-myristate 13-acetate (PMA) to renal LLC-PK1-F+cells caused a rapid decrease in the level of phosphoenolpyruvate carboxykinase (PCK) mRNA and reversed the stimulatory effects of exposure to acidic medium (pH 6.9, 10 mM) or cAMP. In contrast, prolonged treatment with PMA increased the levels of PCK mRNA. The two effects correlated with the membrane translocation and downregulation of the α-isozyme of protein kinase C and were blocked by pretreatment with specific inhibitors of protein kinase C. The rapid decrease in PCK mRNA caused by PMA occurred with a half-life (t½= 1 h) that is significantly faster than that measured during recovery from acid medium or following inhibition of transcription (t½= 4 h). The effect of PMA was reversed by staurosporine, which apparently acts by inhibiting a signaling pathway other than protein kinase C. Staurosporine had no effect on the half-life of the PCK mRNA, but it stimulated the activity of a chloramphenicol acetyltransferase gene that was driven by the initial 490 base pairs of the PCK promoter and transiently transfected into LLC-PK1-F+cells. This effect was additive to that of cAMP, and neither stimulation was reversed by PMA. The stimulatory effect of staurosporine was mapped to the cAMP response element (CRE-1) and P3(II) element of the PCK promoter. The data indicate that, in LLC-PK1-F+cells, activation of protein kinase C decreases the stability of the PCK mRNA, whereas transcription of the PCK gene may be suppressed by a kinase that is inhibited by staurosporine.