Characterization of Cep85 - a new antagonist of Nek2A that is involved in the regulation of centrosome disjunction.
Characterization of Cep85 - a new antagonist of Nek2A that is involved in the regulation of centrosome disjunction.
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Cep85 的表征 - 一种新的 Nek2A 拮抗剂，参与中心体分离的调节
DOI：
10.1242/jcs.171637
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发表时间：
2015-09-01
影响因子：
4
通讯作者：
Yu X
中科院分区：
文献类型：
--
作者：
Chen C;Tian F;Lu L;Wang Y;Xiao Z;Yu C;Yu X
Nek 2参与了有丝分裂初期中心体的分离，促进了双极纺锤体的形成，而Nek 2的过度激活导致了中心体的过早分离。因此，必须严格管制其活动。在这项研究中，我们报告，Cep85，一个未知的中心体蛋白，作为Nek2A的结合伴侣。它与Nek2的亚型A（Nek2A）共定位于中心体，并形成一个颗粒网络，包裹中心粒的近端。与Nek2A的作用相反，Cep85的过表达结合马达蛋白Eg5（也称为KIF11）的抑制导致中心体分离失败。相反，Cep85的缺失导致早熟的中心体分离。我们还定义了Nek2A结合和Cep85内的中心体定位域。虽然Nek2A结合结构域单独足以抑制Nek2A激酶的体外活性，但这两个结构域对于完全抑制细胞中的中心体分离是不可或缺的。因此，我们认为Cep85是一个真正的Nek2A结合伴侣，它围绕中心粒的近端，在那里它与PP1γ（也称为PPP1CC）合作拮抗Nek2A活性，以维持哺乳动物细胞间期中心体的完整性。总结：Cep85作为Nek2A的结合伴侣，通过抑制Nek2A活性来防止间期中心体过早分离。
ABSTRACT Nek2 has been implicated in centrosome disjunction at the onset of mitosis to promote bipolar spindle formation, and hyperactivation of Nek2 leads to the premature centrosome separation. Its activity, therefore, needs to be strictly regulated. In this study, we report that Cep85, an uncharacterized centrosomal protein, acts as a binding partner of Nek2A. It colocalizes with isoform A of Nek2 (Nek2A) at centrosomes and forms a granule meshwork enveloping the proximal ends of centrioles. Opposite to the effects of Nek2A, overexpression of Cep85 in conjunction with inhibition of the motor protein Eg5 (also known as KIF11) leads to the failure of centrosome disjunction. By contrast, depletion of Cep85 results in the precocious centrosome separation. We also define the Nek2A binding and centrosome localization domains within Cep85. Although the Nek2A-binding domain alone is sufficient to inhibit Nek2A kinase activity in vitro, both domains are indispensable for full suppression of centrosome disjunction in cells. Thus, we propose that Cep85 is a bona fide Nek2A-binding partner that surrounds the proximal ends of centrioles where it cooperates with PP1γ (also known as PPP1CC) to antagonize Nek2A activity in order to maintain the centrosome integrity in interphase in mammalian cells. Summary: Cep85 acts as a binding partner of Nek2A to prevent premature centrosome separation in interphase by inhibiting Nek2A activity.