PDF(Pubmed)
Abstract：
The centrosome linker joins the two interphase centrosomes of a cell into one microtubule organizing center. Despite increasing knowledge on linker components, linker diversity in different cell types and their role in cells with supernumerary centrosomes remained unexplored. Here, we identified Ninein as a C-Nap1-anchored centrosome linker component that provides linker function in RPE1 cells while in HCT116 and U2OS cells, Ninein and Rootletin link centrosomes together. In interphase, overamplified centrosomes use the linker for centrosome clustering, where Rootletin gains centrosome linker function in RPE1 cells. Surprisingly, in cells with centrosome overamplification, C-Nap1 loss prolongs metaphase through persistent activation of the spindle assembly checkpoint indicated by BUB1 and MAD1 accumulation at kinetochores. In cells lacking C-Nap1, the reduction of microtubule nucleation at centrosomes and the delay in nuclear envelop rupture in prophase probably cause mitotic defects like multipolar spindle formation and chromosome mis-segregation. These defects are enhanced when the kinesin HSET, which normally clusters multiple centrosomes in mitosis, is partially inhibited indicating a functional interplay between C-Nap1 and centrosome clustering in mitosis.
摘要：
中心体接头将细胞的两个相间中心体连接成一个微管组织中心。尽管对连接器组件的了解越来越多，不同细胞类型的接头多样性及其在具有超数中心体的细胞中的作用仍未被探索。这里,我们确定Ninein是C-Nap1锚定的中心体接头组件，可在RPE1细胞中提供接头功能，而在HCT116和U2OS细胞中，Ninein和Rootletin将中心体连接在一起。在中间阶段，过度扩增的中心体使用接头进行中心体聚类，其中Rootletin在RPE1细胞中获得中心体接头功能。令人惊讶的是,在中心体过度扩增的细胞中，C-Nap1损失通过持续激活主轴组装检查点来延长中期，该检查点由动静脉中的BUB1和MAD1积累指示。在缺乏C-Nap1的细胞中，中心体处微管成核的减少和前期核包膜破裂的延迟可能会导致有丝分裂缺陷，例如多极纺锤体形成和染色体错误分离。当激素水平HSET时，这些缺陷得到增强，通常在有丝分裂中聚集多个中心体，被部分抑制，表明有丝分裂中C-Nap1和中心体聚集之间的功能相互作用。
