Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
Micron Oxford Advanced Bioimaging Unit, Department of Biochemistry, University of Oxford, Oxford, UK.
Curr Biol. 2017 Oct 9;27(19):R1054-R1055. doi: 10.1016/j.cub.2017.08.009.
Centrioles are small barrel-shaped structures that form centrosomes and cilia [1]. Centrioles assemble around a central cartwheel comprising the Sas-6 and Ana2/STIL proteins. The amino termini of nine Sas-6 dimers form a central hub of ∼12 nm radius from which nine dimer spokes radiate, placing the Sas-6 carboxyl termini at the outer edge of the ∼60 nm radius cartwheel [2]. Several centriole proteins are distributed in a toroid around the cartwheel, and super-resolution light microscopy studies have measured the average radii of these ∼100-200 nm radius toroids with a 'precision' - or standard deviation (s.d. or 1σ) - of ±∼10-40 nm. The organization of Ana2/STIL within the cartwheel, however, has not been resolvable. Here, we develop methods to calculate the average toroidal radius of centriolar proteins in the ∼20-60 nm range with a s.d. of just ±∼4-5 nm, revealing that the amino and carboxyl termini of Ana2 are located in the outer cartwheel region.
中心粒是形成中心体和纤毛的小型桶状结构[1]。中心粒围绕由 Sas-6 和 Ana2/STIL 蛋白组成的中央轮辐组装。九个 Sas-6 二聚体的氨基末端形成一个约 12nm 半径的中央轮毂，九个二聚体辐条从这里辐射，将 Sas-6 羧基末端放置在约 60nm 半径轮辐的外边缘[2]。几种中心粒蛋白以轮辐为中心呈环形分布，超分辨率荧光显微镜研究已经测量了这些约 100-200nm 半径轮辐的平均半径，其“精度”或标准偏差（s.d.或 1σ）为±∼10-40nm。然而，轮辐内 Ana2/STIL 的组织尚未得到解决。在这里，我们开发了一种方法，可以计算约 20-60nm 范围内中心粒蛋白的平均环面半径，其标准偏差仅为±∼4-5nm，表明 Ana2 的氨基和羧基末端位于外轮辐区域。
