Biozentrum, University of Basel, 4056 Basel, Switzerland.
Biozentrum, University of Basel, 4056 Basel, Switzerland
Proc Natl Acad Sci U S A. 2014 Jul 15;111(28):E2841-50. doi: 10.1073/pnas.1401777111. Epub 2014 Jun 30.
Primary cilia play critical roles in development and disease. Their assembly is triggered by mature centrioles (basal bodies) and requires centrosomal protein 164kDa (Cep164), a component of distal appendages. Here we show that loss of Cep164 leads to early defects in ciliogenesis, reminiscent of the phenotypic consequences of mutations in TTBK2 (Tau tubulin kinase 2). We identify Cep164 as a likely physiological substrate of TTBK2 and demonstrate that Cep164 and TTBK2 form a complex. We map the interaction domains and demonstrate that complex formation is crucial for the recruitment of TTBK2 to basal bodies. Remarkably, ciliogenesis can be restored in Cep164-depleted cells by expression of chimeric proteins in which TTBK2 is fused to the C-terminal centriole-targeting domain of Cep164. These findings indicate that one of the major functions of Cep164 in ciliogenesis is to recruit active TTBK2 to centrioles. Once positioned, TTBK2 then triggers key events required for ciliogenesis, including removal of CP110 and recruitment of intraflagellar transport proteins. In addition, our data suggest that TTBK2 also acts upstream of Cep164, contributing to the assembly of distal appendages.
初级纤毛在发育和疾病中发挥着关键作用。它们的组装是由成熟的中心粒（基体）触发的，需要中心体蛋白 164kDa（Cep164），这是远端附属物的一个组成部分。在这里，我们表明 Cep164 的缺失会导致纤毛发生的早期缺陷，这让人联想到 TTBK2（微管相关蛋白 Tau 激酶 2）突变的表型后果。我们将 Cep164 鉴定为 TTBK2 的一个潜在生理底物，并证明 Cep164 和 TTBK2 形成复合物。我们确定了相互作用的结构域，并证明复合物的形成对于 TTBK2 向基体的募集至关重要。值得注意的是，通过表达 Cep164 的 C 末端基体靶向结构域融合的嵌合蛋白，可以在 Cep164 耗尽的细胞中恢复纤毛发生。这些发现表明，Cep164 在纤毛发生中的主要功能之一是将活性 TTBK2 募集到基体。一旦定位，TTBK2 就会引发纤毛发生所需的关键事件，包括 CP110 的去除和内鞭毛运输蛋白的募集。此外，我们的数据还表明，TTBK2 也在上游作用于 Cep164，有助于远端附属物的组装。
