The Caenorhabditis elegans pericentriolar material components SPD-2 and SPD-5 are monomeric in the cytoplasm before incorporation into the PCM matrix.
The Caenorhabditis elegans pericentriolar material components SPD-2 and SPD-5 are monomeric in the cytoplasm before incorporation into the PCM matrix.
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DOI：
10.1091/mbc.e13-09-0514
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发表时间：
2014-10-01
影响因子：
3.3
通讯作者：
Hyman AA
中科院分区：
文献类型：
--
作者：
Wueseke O;Bunkenborg J;Hein MY;Zinke A;Viscardi V;Woodruff JB;Oegema K;Mann M;Andersen JS;Hyman AA
虽然秀丽隐杆线虫中心体蛋白SPD-5、RSA-1和RSA-2之间的细胞质相互作用可以在体内检测到，但中心体组装所需的关键蛋白SPD-2和SPD-5主要以单体形式存在，并且与细胞质中的中心体相关激酶PLK-1和AIR-1分离。中心体是动物细胞中主要的微管组织中心。中心体由一对中心粒组成，中心粒周围有一层由细胞质成分组成的中心粒周围物质（PCM）。在秀丽隐杆线虫胚胎中，卷曲螺旋蛋白SPD-5和SPD-2与激酶PLK-1之间的相互作用对PCM组装至关重要。然而，尚不清楚这些相互作用是否促进了加入PCM的细胞质复合物的形成，或者这些组分是否仅在掺入PCM基质期间相互作用。在这里，我们通过结合使用活细胞荧光相关光谱、质谱和流体动力学技术来研究细胞质中PCM成分的天然状态来解决这个问题。我们发现，SPD-2是单体，既不SPD-2也不SPD-5与PLK-1复合存在。SPD-5主要以单体形式存在，但也与PP 2A调节蛋白RSA-1和RSA-2形成复合物，这是中心体微管组织所必需的。这些结果表明SPD-2、SPD-5和PLK-1之间的相互作用不会导致细胞质复合物的形成，而是发生在PCM组装的背景下。
Although cytoplasmic interactions between Caenorhabditis elegans centrosome proteins SPD-5, RSA-1, and RSA-2 can be detected in vivo, the key proteins required for centrosome assembly, SPD-2 and SPD-5, exist mostly as monomers and are separated from the centrosome-related kinases PLK-1 and AIR-1 in the cytoplasm. Centrosomes are the main microtubule-organizing centers in animal cells. Centrosomes consist of a pair of centrioles surrounded by a matrix of pericentriolar material (PCM) that assembles from cytoplasmic components. In Caenorhabditis elegans embryos, interactions between the coiled-coil proteins SPD-5 and SPD-2 and the kinase PLK-1 are critical for PCM assembly. However, it is not known whether these interactions promote the formation of cytoplasmic complexes that are added to the PCM or whether the components interact only during incorporation into the PCM matrix. Here we address this problem by using a combination of live-cell fluorescence correlation spectroscopy, mass spectrometry, and hydrodynamic techniques to investigate the native state of PCM components in the cytoplasm. We show that SPD-2 is monomeric, and neither SPD-2 nor SPD-5 exists in complex with PLK-1. SPD-5 exists mostly as a monomer but also forms complexes with the PP2A-regulatory proteins RSA-1 and RSA-2, which are required for microtubule organization at centrosomes. These results suggest that the interactions between SPD-2, SPD-5, and PLK-1 do not result in formation of cytoplasmic complexes, but instead occur in the context of PCM assembly.