Protein phosphatase Dusp26 associates with KIF3 motor and promotes N-cadherin-mediated cell-cell adhesion
Protein phosphatase Dusp26 associates with KIF3 motor and promotes N-cadherin-mediated cell-cell adhesion
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DOI：
10.1038/onc.2008.431
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发表时间：
2009-02-05
期刊：
影响因子：
8
通讯作者：
Shima, H.
中科院分区：
文献类型：
--
作者：
Tanuma, N.;Nomura, M.;Shima, H.
最近的研究表明，KIF3是一种微管导向的蛋白质马达，在几种癌症相关蛋白的亚细胞运输中具有重要功能，包括β -连环蛋白-钙粘蛋白复合物。在这项研究中，我们报告了蛋白磷酸酶Dusp26作为KIF3马达的一种新的调节剂的鉴定。在这里，我们进行酵母双杂交筛选，并鉴定出Kif3a， KIF3异源三聚体复合物的一个运动亚基，作为一种新的dusp26结合蛋白。共免疫沉淀和共定位实验表明，Dusp26不仅与Kif3a结合，还与KIF3复合物的另一个亚基Kap3结合。体外去磷酸化实验和完整细胞中Dusp26突变体的分析强烈表明，Dusp26主要通过与Kif3a的相互作用被募集到KIF3马达中，从而使Kap3去磷酸化。强制表达Dusp26，而不是其催化失活突变体Dusp26，促进了β -catenin/N-cadherin（一种已建立的KIF3货物）向细胞-细胞连接位点的分布，导致细胞-细胞粘附性增加。我们还发现Dusp26 mRNA在人胶质母细胞瘤样本中表达下调。这些结果提示了Dusp26在细胞内运输和细胞-细胞粘附中的功能。Dusp26的下调可能与胶质瘤的恶性表型有关。
Recent studies have demonstrated essential functions for KIF3, a microtubule-directed protein motor, in subcellular transport of several cancer-relatedproteins, including the beta-catenin-cadherin(s) complex. In this study, we report identification of the protein-phosphatase Dusp26 as a novel regulator of the KIF3 motor. Here we undertake yeast two-hybridscreening and identify Kif3a, a motor subunit of the KIF3 heterotrimeric complex, as a novel Dusp26-binding protein. Co-immunoprecipitation and colocalization experiments revealed that Dusp26 associates not only with Kif3a, but also with Kap3, another subunit of the KIF3 complex. Dephosphorylation experiments in vitro and analysis using mutant forms of Dusp26 in intact cells strongly suggested that Dusp26 is recruited to the KIF3 motor mainly by interaction with Kif3a, and thereby dephosphorylates Kap3. Forced expression of Dusp26, but not its catalytically inactive mutant, promotedd istribution of beta-catenin/N-cadherin, an established KIF3 cargo, to cell-cell junction sites, resulting in increased cell-cell adhesiveness. We also showed that Dusp26 mRNA expression was downregulated in human glioblastoma samples. These results suggest previously unidentified functions of Dusp26 in intracellular transport and cell-cell adhesion. Downregulation of Dusp26 may contribute to malignant phenotypes of glioma.