Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan.
J Cell Biol. 2013 Jul 22;202(2):211-9. doi: 10.1083/jcb.201212060. Epub 2013 Jul 15.
Centriole duplication begins with the formation of a single procentriole next to a preexisting centriole. CPAP (centrosomal protein 4.1-associated protein) was previously reported to participate in centriole elongation. Here, we show that CEP120 is a cell cycle-regulated protein that directly interacts with CPAP and is required for centriole duplication. CEP120 levels increased gradually from early S to G2/M and decreased significantly after mitosis. Forced overexpression of either CEP120 or CPAP not only induced the assembly of overly long centrioles but also produced atypical supernumerary centrioles that grew from these long centrioles. Depletion of CEP120 inhibited CPAP-induced centriole elongation and vice versa, implying that these proteins work together to regulate centriole elongation. Furthermore, CEP120 was found to contain an N-terminal microtubule-binding domain, a C-terminal dimerization domain, and a centriolar localization domain. Overexpression of a microtubule binding-defective CEP120-K76A mutant significantly suppressed the formation of elongated centrioles. Together, our results indicate that CEP120 is a CPAP-interacting protein that positively regulates centriole elongation.
中心体复制始于在一个预先存在的中心体旁边形成一个单一的前中心体。CPAP（中心体蛋白 4.1 相关蛋白）先前被报道参与中心体的伸长。在这里，我们表明 CEP120 是一种细胞周期调节蛋白，它直接与 CPAP 相互作用，是中心体复制所必需的。CEP120 水平从早期 S 期逐渐增加到 G2/M 期，在有丝分裂后显著下降。强制过表达 CEP120 或 CPAP 不仅诱导过度长的中心体组装，而且还产生了从这些长中心体生长的异常多余的中心体。CEP120 的耗竭抑制了 CPAP 诱导的中心体伸长，反之亦然，这表明这些蛋白一起共同调节中心体伸长。此外，还发现 CEP120 含有一个 N 端微管结合结构域、一个 C 端二聚化结构域和一个中心体定位结构域。微管结合缺陷的 CEP120-K76A 突变体的过表达显著抑制了伸长中心体的形成。总之，我们的结果表明 CEP120 是一种与 CPAP 相互作用的蛋白，正向调节中心体伸长。
