GAK, a regulator of clathrin-mediated membrane trafficking, localizes not only in the cytoplasm but also in the nucleus
GAK, a regulator of clathrin-mediated membrane trafficking, localizes not only in the cytoplasm but also in the nucleus
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DOI：
10.1111/j.1365-2443.2009.01296.x
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发表时间：
2009-05-01
期刊：
影响因子：
2.1
通讯作者：
Nojima, Hiroshi
中科院分区：
文献类型：
--
作者：
Sato, Jun;Shimizu, Hiroyuki;Nojima, Hiroshi
普遍表达的细胞周期蛋白 G 相关激酶 (GAK) 调节细胞质中网格蛋白介导的膜运输。然而，GAK 与与膜运输无关的核蛋白 Cyclin G1 的关联表明 GAK 在细胞核中的作用尚未确定。事实上，我们在这里通过免疫染色、GFP-GAK 的异位表达和使用解剖的 GAK 片段的下拉分析报告，GAK 定位在细胞质和细胞核中。 GAK 不仅与细胞周期蛋白 G1 形成复合物，还与其他核蛋白形成复合物，例如 p53、网格蛋白重链 (CHC) 和蛋白磷酸酶 2A (PP2A) B'alpha 1。此外，CHC 通过不同的结构域与 GAK 结合，具体取决于它是在细胞质还是细胞核中。免疫染色显示大约20%至30%的B'α1、细胞周期蛋白G1和p53与核GAK形成复合物。 CHC 还在细胞核中显示出点，并且几乎所有细胞核 CHC 信号都与 GAK 共定位。这些观察结果共同表明了 GAK 在细胞核中的重要功能。
The ubiquitously expressed Cyclin G-associated kinase (GAK) regulates clathrin-mediated membrane trafficking in the cytoplasm. However, the association of GAK with a nuclear protein Cyclin G1 that is unrelated to membrane trafficking suggests an unidentified role of GAK in the nucleus. Indeed, we report here that GAK localizes in both cytoplasm and nucleus by immunostaining, ectopic expression of GFP-GAK and pull-down assays using dissected GAK fragments. GAK forms complexes not only with cyclin G1 but also with other nuclear proteins such as p53, clathrin heavy chain (CHC) and protein phosphatase 2A (PP2A) B'alpha 1. Moreover, CHC associates with GAK via a different domain depending on whether it is in the cytoplasm or nucleus. Immunostaining revealed that about 20 similar to 30% of B'alpha 1, cyclin G1 and p53 complex with nuclear GAK. CHC also displayed dots in the nucleus and almost all nuclear CHC signals colocalized with GAK. These observations together suggest an important function of GAK in the nucleus.