Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology, EPFL, Lausanne, Switzerland.
Cell. 2011 Feb 4;144(3):364-75. doi: 10.1016/j.cell.2011.01.008.
The centriole, and the related basal body, is an ancient organelle characterized by a universal 9-fold radial symmetry and is critical for generating cilia, flagella, and centrosomes. The mechanisms directing centriole formation are incompletely understood and represent a fundamental open question in biology. Here, we demonstrate that the centriolar protein SAS-6 forms rod-shaped homodimers that interact through their N-terminal domains to form oligomers. We establish that such oligomerization is essential for centriole formation in C. elegans and human cells. We further generate a structural model of the related protein Bld12p from C. reinhardtii, in which nine homodimers assemble into a ring from which nine coiled-coil rods radiate outward. Moreover, we demonstrate that recombinant Bld12p self-assembles into structures akin to the central hub of the cartwheel, which serves as a scaffold for centriole formation. Overall, our findings establish a structural basis for the universal 9-fold symmetry of centrioles.
中心粒和相关的基体是一种古老的细胞器，其特征是具有普遍的 9 重放射状对称性，对于产生纤毛、鞭毛和中心体至关重要。指导中心粒形成的机制尚不完全清楚，这是生物学中的一个基本开放性问题。在这里，我们证明中心粒蛋白 SAS-6 形成棒状同源二聚体，通过其 N 端结构域相互作用形成寡聚体。我们确定这种寡聚化对于秀丽隐杆线虫和人类细胞中的中心粒形成是必不可少的。我们进一步生成了来自莱茵衣藻的相关蛋白 Bld12p 的结构模型，其中九个同源二聚体组装成一个环，从该环中向外辐射出九个螺旋卷曲的棒。此外，我们证明重组 Bld12p 可以自组装成类似于车轮辐条中心的结构，作为中心粒形成的支架。总的来说，我们的发现为中心粒的普遍 9 重对称性建立了结构基础。
