VIMENTIN SERVES AS A PHOSPHATE SINK DURING THE APPARENT ACTIVATION OF PROTEIN-KINASES BY OKADAIC ACID IN MAMMALIAN-CELLS
VIMENTIN SERVES AS A PHOSPHATE SINK DURING THE APPARENT ACTIVATION OF PROTEIN-KINASES BY OKADAIC ACID IN MAMMALIAN-CELLS
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DOI：
10.1002/jcb.240530209
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发表时间：
1993-10-01
影响因子：
4
通讯作者：
CHEN, KD
中科院分区：
文献类型：
--
作者：
LAI, YK;LEE, WC;CHEN, KD
采用免疫印迹法和扫描密度法测定了来源于大鼠和人组织的4种哺乳动物细胞系的静脉蛋白含量。按细胞体积计算，9L、KD和HeLa细胞中波形蛋白含量分别为206.6、151.6和19.1 ng/mul。A431细胞缺乏波形蛋白。600 nM冈田酸处理1小时后，蛋白磷酸化增强。在蛋白激酶的明显激活过程中，波形蛋白被过度磷酸化，而其他非波形蛋白磷酸化水平在9L和KD细胞中受到的影响相对较小。相比之下，在oa处理的HeLa和A431细胞中，细胞角蛋白和其他非vimentin蛋白被严重磷酸化。回归分析表明，四种细胞系中非波形蛋白磷酸化水平的相对升高与波形蛋白含量呈负相关[r2 = -0.985]。这些观察结果强烈表明，vimentin作为一个磷酸盐汇，通过它，由磷酸酶抑制造成的“过度激酶活性”的影响被减弱。(C) 1993 Wiley-Liss, Inc。
The vimentin contents of four mammalian cell lines originating from rat and human tissues were determined by immunoblotting and scanning densitometry. On per cell volume basis, vimentin content in 9L, KD, and HeLa cells was found to be 206.6, 151.6, and 19.1 ng/mul, respectively. A431 cells were devoid of vimentin. Protein phosphorylation was augmented by treatment of 600 nM okadaic acid for 1 h in these cells. During the apparent activation of protein kinases, vimentin became hyperphosphorylated and the phosphorylation level of other nonvimentin phosphoproteins was relatively little affected in 9L and KD cells. In contrast, cytokeratins and other nonvimentin proteins were heavily phosphorylated in OA-treated HeLa and A431 cells. Regression analysis indicated that the relative increase in phosphorylation level of nonvimentin phosphoproteins was inversely correlated to the contents of vimentin in the four cell lines [r2 = -0.985]. These observations strongly suggest that vimentin acts as a phosphate sink by which the effects of ''excess kinase activity'' inflicted by phosphatases inhibition was attenuated. (C) 1993 Wiley-Liss, Inc.