van Breugel Mark, Wilcken Rainer, McLaughlin Stephen H, Rutherford Trevor J, Johnson Christopher M
Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.
Elife. 2014 Jan 1;3:e01812. doi: 10.7554/eLife.01812.
Centrioles are cylindrical cell organelles with a ninefold symmetric peripheral microtubule array that is essential to template cilia and flagella. They are built around a central cartwheel assembly that is organized through homo-oligomerization of the centriolar protein SAS-6, but whether SAS-6 self-assembly can dictate cartwheel and thereby centriole symmetry is unclear. Here we show that Leishmania major SAS-6 crystallizes as a 9-fold symmetric cartwheel and provide the X-ray structure of this assembly at a resolution of 3.5 Å. We furthermore demonstrate that oligomerization of Leishmania SAS-6 can be inhibited by a small molecule in vitro and provide indications for its binding site. Our results firmly establish that SAS-6 can impose cartwheel symmetry on its own and indicate how this process might occur mechanistically in vivo. Importantly, our data also provide a proof-of-principle that inhibition of SAS-6 oligomerization by small molecules is feasible. DOI: http://dx.doi.org/10.7554/eLife.01812.001.
中心粒是一种圆柱形的细胞器，其具有九重对称的外周微管阵列，这对于纤毛和鞭毛的形成至关重要。它们围绕着一个中心轮状结构组装而成，该结构通过中心粒蛋白SAS-6的同型寡聚化来组织，但SAS-6的自组装是否能够决定轮状结构从而决定中心粒的对称性尚不清楚。在这里，我们展示了利什曼原虫主要种的SAS-6结晶为九重对称的轮状结构，并以3.5埃的分辨率提供了该组装体的X射线结构。我们还证明了利什曼原虫SAS-6的寡聚化在体外可被一种小分子抑制，并给出了其结合位点的相关线索。我们的结果确凿地证实了SAS-6能够自行赋予轮状结构对称性，并指出了这一过程在体内可能的发生机制。重要的是，我们的数据还提供了一个原理证明，即小分子抑制SAS-6寡聚化是可行的。DOI: http://dx.doi.org/10.7554/eLife.01812.001
