Martinez-Garay Isabel, Rustom Amin, Gerdes Hans-Hermann, Kutsche Kerstin
Institut für Humangenetik, Universitätsklinikum Hamburg-Eppendorf, Butenfeld 42, D-22529 Hamburg, Germany.
Genomics. 2006 Feb;87(2):243-53. doi: 10.1016/j.ygeno.2005.11.006. Epub 2006 Jan 10.
Centrosomes are the major microtubule nucleating center in the cell; they also contribute to spindle pole organization and play a role in cell cycle progression as well as completing cytokinesis. Here we describe the molecular characterization of a novel human gene, CEP55, located in 10q23.33 that is expressed in multiple tissues and various cancer cell lines. Sequence analysis of the cDNA predicted a protein of 464 amino acids with several putative coiled-coil domains that are responsible for protein-protein interactions. Indeed, we found homodimerization of CEP55 by coimmunoprecipitation. Subcellular localization analysis revealed that endogenous CEP55 as well as an EGFP-CEP55 fusion protein is present at the centrosome throughout mitosis, whereas it also appears at the cleavage furrow in late anaphase and in the midbody in cytokinesis. Neither nocodazole nor taxol interfered with centrosome association of endogenous CEP55, suggesting that it directly interacts with centrosome components rather than with microtubules. In microtubule regrowth assays, overexpression of CEP55 did not enhance or inhibit microtubule nucleation. Together, these data suggest a possible involvement of CEP55 in centrosome-dependent cellular functions, such as centrosome duplication and/or cell cycle progression, or in the regulation of cytokinesis.
中心体是细胞中主要的微管成核中心；它们还对纺锤体极的组织有贡献，并在细胞周期进程以及完成胞质分裂中发挥作用。在此，我们描述了一个位于10q23.33的新型人类基因CEP55的分子特征，该基因在多种组织和各种癌细胞系中表达。对cDNA的序列分析预测了一个由464个氨基酸组成的蛋白质，其具有几个负责蛋白质 - 蛋白质相互作用的假定卷曲螺旋结构域。事实上，我们通过免疫共沉淀发现了CEP55的同源二聚化。亚细胞定位分析表明，内源性CEP55以及EGFP - CEP55融合蛋白在整个有丝分裂过程中都存在于中心体，而在后期晚期它也出现在分裂沟处，在胞质分裂过程中出现在中间体。诺考达唑和紫杉醇都没有干扰内源性CEP55与中心体的结合，这表明它直接与中心体成分相互作用，而不是与微管相互作用。在微管再生试验中，CEP55的过表达没有增强或抑制微管成核。总之，这些数据表明CEP55可能参与依赖中心体的细胞功能，如中心体复制和/或细胞周期进程，或参与胞质分裂的调控。
