Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA
Department of Genetics, Cell Biology and Development, University of Minnesota, Minneapolis, MN 55455, USA.
J Cell Sci. 2020 Dec 29;133(24):jcs240267. doi: 10.1242/jcs.240267.
The centrosome, which consists of centrioles and pericentriolar material (PCM), becomes mature and assembles mitotic spindles by increasing the number of microtubules (MTs) emanating from the PCM. Among the molecules involved in centrosome maturation, Cep192 and Aurora A (AurA, also known as AURKA) are primarily responsible for recruitment of γ-tubulin and MT nucleators, whereas pericentrin (PCNT) is required for PCM organization. However, the role of Cep215 (also known as CDK5RAP2) in centrosome maturation remains elusive. Cep215 possesses binding domains for γ-tubulin, PCNT and MT motors that transport acentrosomal MTs towards the centrosome. We identify a mitosis-specific centrosome-targeting domain of Cep215 (215N) that interacts with Cep192 and phosphorylated AurA (pAurA). Cep192 is essential for targeting 215N to centrosomes, and centrosomal localization of 215N and pAurA is mutually dependent. Cep215 has a relatively minor role in γ-tubulin recruitment to the mitotic centrosome. However, it has been shown previously that this protein is important for connecting mitotic centrosomes to spindle poles. Based on the results of rescue experiments using versions of Cep215 with different domain deletions, we conclude that Cep215 plays a role in maintaining the structural integrity of the spindle pole by providing a platform for the molecules involved in centrosome maturation.
中心体由中心粒和中心体周围物质（PCM）组成，通过增加从 PCM 发出的微管（MTs）的数量而成熟并组装有丝分裂纺锤体。在参与中心体成熟的分子中，Cep192 和 Aurora A（AurA，也称为 AURKA）主要负责招募γ-微管蛋白和 MT 引发因子，而中心体蛋白（PCNT）则是 PCM 组织所必需的。然而，Cep215（也称为 CDK5RAP2）在中心体成熟中的作用仍不清楚。Cep215 具有与γ-微管蛋白、PCNT 和 MT 马达结合的结构域，这些马达将无中心体的 MT 运往中心体。我们确定了 Cep215 的一个有丝分裂特异性中心体靶向结构域（215N），它与 Cep192 和磷酸化的 AurA（pAurA）相互作用。Cep192 对于将 215N 靶向中心体是必需的，并且 215N 和 pAurA 的中心体定位是相互依赖的。Cep215 在将γ-微管蛋白募集到有丝分裂中心体中的作用相对较小。然而，先前已经表明，该蛋白对于将有丝分裂中心体连接到纺锤体极很重要。基于使用具有不同结构域缺失的 Cep215 版本进行的挽救实验的结果，我们得出结论，Cep215 通过为参与中心体成熟的分子提供平台，在维持纺锤体极的结构完整性方面发挥作用。
