Momotani Ko, Khromov Alexander S, Miyake Tsuyoshi, Stukenberg P Todd, Somlyo Avril V
Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908, USA.
Biochem J. 2008 Jun 1;412(2):265-73. doi: 10.1042/BJ20071501.
The present study demonstrates different functional domains of a recently described centrosomal protein, Cep57 (centrosomal protein 57). Endogenous Cep57 protein and ectopic expression of full-length protein or the N-terminal coiled-coil domain localize to the centrosome internal to gamma-tubulin, suggesting that it is either on both centrioles or on a centromatrix component. The N-terminus can also multimerize with the N-terminus of other Cep57 molecules. The C-terminus contains a second coiled-coil domain that directly binds to MTs (microtubules). This domain both nucleates and bundles MTs in vitro. This activity was also seen in vivo, as overexpression of full-length Cep57 or the C-terminus generates nocodazole-resistant MT cables in cells. Based on the present findings, we propose that Cep57 serves as a link with its N-terminus anchored to the centriole or centromatrix and its C-terminus to MTs.
本研究展示了一种最近描述的中心体蛋白Cep57（中心体蛋白57）的不同功能结构域。内源性Cep57蛋白以及全长蛋白或N端卷曲螺旋结构域的异位表达定位于γ-微管蛋白内部的中心体，这表明它要么在两个中心粒上，要么在着丝粒基质成分上。N端也能与其他Cep57分子的N端多聚化。C端包含第二个卷曲螺旋结构域，可直接与微管（MTs）结合。该结构域在体外既能使微管成核，又能使微管成束。在体内也观察到了这种活性，因为全长Cep57或C端的过表达会在细胞中产生抗诺考达唑的微管束。基于目前的研究结果，我们提出Cep57起到一种连接作用，其N端锚定在中心粒或着丝粒基质上，C端连接到微管上。
