Functional characterization of CP148, a novel key component for centrosome integrity in Dictyostelium
Functional characterization of CP148, a novel key component for centrosome integrity in Dictyostelium
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DOI：
10.1007/s00018-011-0904-2
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发表时间：
2012-06-01
影响因子：
8
通讯作者：
Graef, Ralph
中科院分区：
文献类型：
--
作者：
Kuhnert, Oliver;Baumann, Otto;Graef, Ralph
中心体由一个层状的核心结构组成，周围环绕着一个微管成核的日冕。通过核膜的紧密连接将胞浆中心体与核基质内的簇生着丝粒连接起来。在G2/M时，电晕解离，核心结构重复，产生两个纺锤极。CP148是一种新的中心体冠状卷曲蛋白。GFP-CP148在中心体的存在和不存在依赖于细胞周期，这与前期冠层的解离和末期冠层的重塑有关。在细胞分裂末期，GFP-CP148形成胞浆区，胞浆区聚集并与中心体结合。这解释了在GFP-CP148强过表达时出现的冠状肥大。RNAi耗尽CP148导致电晕实质丢失和间期微管的解体。令人惊讶的是，有丝分裂纺锤体和星形微管的形成没有受到影响。因此，在间期和有丝分裂过程中，微管核复合体通过不同的方式与中心体核心成分结合。此外，CP148 RNAi导致着丝粒的分散，改变了SUN1在核膜上的分布，表明CP148在着丝粒和着丝粒之间的连锁中发挥了作用。综上所述，CP148是中心体冠层形成的关键因子，而中心体冠层又是中心体/着丝粒连接所必需的。
The centrosome consists of a layered core structure surrounded by a microtubule-nucleating corona. A tight linkage through the nuclear envelope connects the cytosolic centrosome with the clustered centromeres within the nuclear matrix. At G2/M the corona dissociates, and the core structure duplicates, yielding two spindle poles. CP148 is a novel coiled coil protein of the centrosomal corona. GFP-CP148 exhibited cell cycle-dependent presence and absence at the centrosome, which correlates with dissociation of the corona in prophase and its reformation in late telophase. During telophase, GFP-CP148 formed cytosolic foci, which coalesced and joined the centrosome. This explains the hypertrophic appearance of the corona upon strong overexpression of GFP-CP148. Depletion of CP148 by RNAi caused virtual loss of the corona and disorganization of interphase microtubules. Surprisingly, formation of the mitotic spindle and astral microtubules was unaffected. Thus, microtubule nucleation complexes associate with centrosomal core components through different means during interphase and mitosis. Furthermore, CP148 RNAi caused dispersal of centromeres and altered Sun1 distribution at the nuclear envelope, suggesting a role of CP148 in the linkage between centrosomes and centromeres. Taken together, CP148 is an essential factor for the formation of the centrosomal corona, which in turn is required for centrosome/centromere linkage.