DEPHOSPHORYLATION OF THE FOCAL ADHESION PROTEIN VASP IN-VITRO AND IN INTACT HUMAN PLATELETS
DEPHOSPHORYLATION OF THE FOCAL ADHESION PROTEIN VASP IN-VITRO AND IN INTACT HUMAN PLATELETS
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DOI：
10.1016/0014-5793(95)00817-s
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发表时间：
1995-08-21
期刊：
影响因子：
3.5
通讯作者：
WALTER, U
中科院分区：
文献类型：
--
作者：
ABEL, K;MIESKES, G;WALTER, U
局灶黏附蛋白VASP是信号转导途径和微丝系统之间的可能联系，在体外和完整细胞中被cAMP-和cgmp依赖性蛋白激酶磷酸化。本文报道了丝氨酸/苏氨酸蛋白磷酸酶（PP） PP1、PP2A、PP2B和PP2C对体外VASP去磷酸化的影响。磷酸酶对VASP个别磷酸化位点的去磷酸化选择性不同。冈田酸是一种有效的PP1和PP2A抑制剂，用冈田酸孵育人血小板可引起磷酸化VASP的积累，这表明完整细胞中VASP的磷酸化状态在很大程度上受丝氨酸/苏氨酸蛋白磷酸酶的调节。此外，磷酸化camp依赖性蛋白激酶底物(s)的积累似乎解释了冈田酸对血小板功能的抑制作用。
The focal adhesion protein VASP, a possible link between signal transduction pathways and the microfilament system, is phosphorylated by both cAMP- and cGMP-dependent protein kinases in vitro and in intact cells. Here, the analysis of VASP dephosphorylation by the serine/threonine protein phosphatases (PP) PP1, PP2A, PP2B and PP2C in vitro is reported. The phosphatases differed in their selectivity with respect to the dephosphorylation of individual VASP phosphorylation sites. Incubation of human platelets with okadaic acid, a potent inhibitor of PP1 and PP2A, caused the accumulation of phosphorylated VASP indicating that the phosphorylation status of VASP in intact cells is regulated to a major extent by serine/threonine protein phosphatases. Furthermore, the accumulation of phosphorylated cAMP-dependent protein kinase substrate(s) appears to account for inhibitory effects of okadaic acid on platelet function.