Nek8 regulates the expression and localization of polycystin-1 and polycystin-2
Nek8 regulates the expression and localization of polycystin-1 and polycystin-2
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DOI：
10.1681/asn.2006090985
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发表时间：
2008-03-01
影响因子：
13.6
通讯作者：
Zhou, Jing
中科院分区：
文献类型：
--
作者：
Sohara, Eisei;Luo, Ying;Zhou, Jing
nek 8是一种丝氨酸/苏氨酸激酶，在jck（幼年型囊性肾）小鼠（常染色体隐性遗传的幼年型多囊肾病模型）中发生突变，但其功能尚不清楚。我们使用Jck小鼠来研究Nek 8与其他与多囊肾疾病有关的蛋白质之间的功能关系。在野生型小鼠的集合小管和集合管中，我们发现Nek 8定位于初级纤毛的近端部分，并且在胞质溶胶中微弱地检测到。然而，在jck突变体中，Nek 8被发现沿着纤毛的整个长度。免疫共沉淀实验表明，Nek 8与多囊蛋白-2相互作用，但不与多囊蛋白-1，和jck突变不影响这种相互作用。Western blot分析和实时荧光定量PCR结果显示，jck小鼠肾脏中多囊蛋白-1（PC 1）和多囊蛋白-2（PC 2）的蛋白和mRNA表达均增加。jck突变还导致PC 2的异常磷酸化，这与PC 1和PC 2的更长纤毛和纤毛积累有关。我们的数据表明，Nek 8与多囊蛋白的信号转导通路相互作用，并可能控制这些纤毛蛋白的靶向。Nek 8功能障碍可能通过改变远端肾单位纤毛的结构和功能而导致囊肿发生。
Nek8 is a serine/threonine kinase that is mutated in the jck (juvenile cystic kidneys) mouse, a model of autosomal recessive juvenile polycystic kidney disease, but its function is poorly understood. We used the Jck mouse to study the functional relationship between Nek8 and other proteins that have been implicated in polycystic kidney diseases. In the collecting tubules and collecting ducts of wild-type mice, we found that Nek8 was localized to the proximal portion of primary cilia and was weakly detected in the cytosol. In the jck mutant, however, Nek8 was found along the entire length of cilia. Coimmunoprecipitation experiments demonstrated that Nek8 interacted with polycystin-2, but not with polycystin-1, and that the jck mutation did not affect this interaction. Western blot analysis and real-time reverse transcriptase PCR revealed that the protein and mRNA expression of polycystin-1 (PC1) and polycystin-2 (PC2) were increased in jck mouse kidneys. The jck mutation also led to abnormal phosphorylatin of PC2, and this was associated with longer cilia and ciliary accumulation of PC1 and PC2. Our data suggests that Nek8 interacts with the signal transduction pathways of the polycystins and may control the targeting of these ciliary proteins. Dysfunction Nek8 may lead to cystogenesis by altering the structure and function of cilia in the distal nephron.