中文摘要：

目的：研究cAMP依赖的蛋白激酶（cAMP dependent protein kinase，PKA）、糖原合成酶激酶-3β（GSK-3β）和细胞周期依赖性蛋白激酶5（cyclin—dependent kinase 5，cdk5）在体外和培养的细胞中对tau蛋白位点特异性磷酸化的调节作用。方法：以人最长的异构体tau441作为底物，通过蛋白质印迹分析，观察以上3种酶对tau蛋白位点特异性磷酸化的调节作用。结果：PKA在体外能够磷酸化Ser214、Ser262、Ser409，但在培养的细胞中，PKA的激活仅使得tau蛋白在Ser214位点的磷酸化增加，而不能磷酸化Ser262和Ser409。在体外和培养的细胞中，GSK-3β和cdk5均能磷酸化tau蛋白许多位点，包括Thr181、Ser199、Ser202、Thr205、Thr212、Thr217、Ser396、Ser404，使得tau蛋白的迁移减慢。结论：在培养的细胞中，PKA的激活使得tau蛋白在Ser214位点的磷酸化增加。GSK-3β能更好地磷酸化tau蛋白微管结合域下游的磷酸化位点，而cdk5则更容易磷酸化其上游的位点。

英文摘要：

Objective：To investigate the site- specifically phsophoarylated regulation of the PKA, GSK -313, and cdk5 on Tau in vitro and in cultured cells. Methods：Using western blot assay to study the site -specifically phsophoarylated regulation of the PKA, GSK - 3β, and cdk5 on tau441 ,longest isoform of human tau, in vitro and in cultured cells. Results：We found that in vitro, PKA phosphorylated tau at Ser214, Ser262, and Ser409 while in cultured CHO cells, activation of PKA increased tau phosphorylation at Ser214, but not at Ser262 and Ser409. Both in vitro and in cultured cells, GSK -3β and cdk5 phosphorylated tau at Thr181 , Ser199, Ser202, Thr205, Thr212, Thr217, Ser396, and Ser404, and because of the phosphorylation, tau mobility shifted up. Conclusion ：Phosphorylation of tau by PKA at Thr214 is enhanced in cultured cells. GSK - 3 β is more favorable for phosphorylating the sites at the at C - terminal of microtubule binding domain than at N - terminal of this domain. In constrast, cdk5 phosphorylated tau is more efficient at N - terminal of the microtubule binding domain than at C - terminal of this domain.