A novel pool of protein phosphatase 2A is associated with microtubules and is regulated during the cell cycle.
A novel pool of protein phosphatase 2A is associated with microtubules and is regulated during the cell cycle.
复制标题
蛋白质磷酸酶2a的新型池与微管有关，并在细胞周期中受到调节。
DOI：
10.1083/jcb.128.6.1131
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发表时间：
1995-03
影响因子：
7.8
通讯作者：
Mumby, M C
中科院分区：
文献类型：
--
作者：
Sontag, E;Nunbhakdi-Craig, V;Bloom, G S;Mumby, M C
免疫荧光显微镜显示，在神经元和非神经元细胞的微管蛋白磷酸酶2A（PP2A）的存在。间期和有丝分裂纺锤体微管，以及中心体，都标记有抗体对个别PP2A亚基，表明AB α C全酶与微管。生物化学分析表明，PP2A可以可逆地结合到微管在体外，约75%的PP2A的胞质提取物可以与微管相互作用。微管相关PP2A的活性在细胞周期中受到不同的调节。酶活性在S期较高，在G1期居中，而在G2和M期比S期低20倍。微管结合的PP2A的量在整个细胞周期中保持恒定，这意味着其酶活性的细胞周期调节涉及微管以外的因素。这些结果提高了PP2A调节细胞周期依赖性微管功能，如核分裂和膜运输的可能性。
Immunofluorescence microscopy revealed the presence of protein phosphatase 2A (PP2A) on microtubules in neuronal and nonneuronal cells. Interphase and mitotic spindle microtubules, as well as centrosomes, were all labeled with antibodies against individual PP2A subunits, showing that the AB alpha C holoenzyme is associated with microtubules. Biochemical analysis showed that PP2A could be reversibly bound to microtubules in vitro and that approximately 75% of the PP2A in cytosolic extracts could interact with microtubules. The activity of microtubule-associated PP2A was differentially regulated during the cell cycle. Enzymatic activity was high during S phase and intermediate during G1, while the activity in G2 and M was 20-fold lower than during S phase. The amount of microtubule-bound PP2A remained constant throughout the cell cycle, implying that cell cycle regulation of its enzymatic activity involves factors other than microtubules. These results raise the possibility that PP2A regulates cell cycle-dependent microtubule functions, such as karyokinesis and membrane transport.