国家自然基金项目(30170221,30100057,30370560),国家杰出青年基金项目(39925012),国家基础研究发展规划项目(G199905400)和美国Li基金会资助.
This work was supported by grants from The National Natural Sciences Foundation of China (39925012, 30100057,30170221,30370560), The Major State Basic Research Development Program of China (G1999054007) and a grant from the Li Foundation, USA.
微管相关蛋白MAP1b的生物学活性受其磷酸化修饰的调节,后者则受相应的蛋白激酶和蛋白磷酸酯酶(PP)调控.为研究蛋白磷酸酯酶在脑内对MAP1b磷酸化的调控作用,采用有代谢活性的大鼠脑片作为模型,分别应用冈田酸(okadaic acid)和cyclosporin A选择性地抑制PP2A 和PP2B活性,来研究其对脑内蛋白磷酸酯酶MAP1b磷酸化的调控.采用特异性的MAP1bⅠ型磷酸化依赖性抗体522和免疫印迹技术检测MAP1bⅠ型磷酸化.结果表明,当PP2A被okadaic acid选择性抑制后,MAP1bⅠ型磷酸化明显增加.而PP2B被选择性地抑制后,MAP1b磷酸化的变化不大.免疫组化染色显示,MAP1b广泛分布于鼠大脑神经元和突起中,与对照组相比,在PP2A抑制的脑片中抗体522的免疫活性在神经元中明显升高.上述结果表明,PP2A是脑中调控MAP1bⅠ型磷酸化的主要蛋白磷酸酯酶.
The function of the neuronal microtubule-associated protein MAP1b is regulated by the degree of its phosphorylation, which is controlled in turn by activities of protein kinases and protein phosphatases (PP). To investigate the role of PP in the regulation of phosphorylation of MAP1b, okadaic acid and cyclosporin A were used to selectively inhibit PP2A and PP2B activities, respectively, in metabolically competent rat brain slices. The alterations of phosphorylation levels at mode Ⅰ sites of MAP1b were examined by Western blots using a phosphorylation-dependent MAP1b antibody 522 that specifically recognizes MAP1b phosphorylated at mode Ⅰ sites. The inhibition of PP2A, but not PP2B, was found to induce a marked increase in phosphorylation of MAP1b. Immunohistochemically, MAP1b was found ubiquitously in neuronal cell bodies and processes. A marked increase in neuronal staining in okadaic acid-treated tissue was observed with antibody 522 to the phosphorylated MAP1b. These results suggest that PP2A is the major PP that participates in regulation of the phosphorylation of MAP1b at the mode Ⅰ phosphorylation sites.
王丽岳,刁路明,田青,王建枝,龚成新.蛋白磷酸酯酶2A调节微管相关蛋白1b的磷酸化[J].生物化学与生物物理进展,2004,31(11):986-990
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