Department of Anatomy, Histology and Developmental Biology, Shenzhen University Health Science Centre, Shenzhen, 518000, China.
Medical AI Laboratory, School of Biomedical Engineering, Shenzhen University Health Science Centre, Shenzhen, 518000, China.
BMC Biol. 2022 Oct 24;20(1):240. doi: 10.1186/s12915-022-01437-6.
The centrosome is one of the most important non-membranous organelles regulating microtubule organization and progression of cell mitosis. The coiled-coil alpha-helical rod protein 1 (CCHCR1, also known as HCR) gene is considered to be a psoriasis susceptibility gene, and the protein is suggested to be localized to the P-bodies and centrosomes in mammalian cells. However, the exact cellular function of HCR and its potential regulatory role in the centrosomes remain unexplored.
We found that HCR interacts directly with astrin, a key factor in centrosome maturation and mitosis. Immunoprecipitation assays showed that the coiled-coil region present in the C-terminus of HCR and astrin respectively mediated the interaction between them. Astrin not only recruits HCR to the centrosome, but also protects HCR from ubiquitin-proteasome-mediated degradation. In addition, depletion of either HCR or astrin significantly reduced centrosome localization of CEP72 and subsequent MCPH proteins, including CEP152, CDK5RAP2, and CEP63. The absence of HCR also caused centriole duplication defects and mitotic errors, resulting in multipolar spindle formation, genomic instability, and DNA damage.
We conclude that HCR is localized and stabilized at the centrosome by directly binding to astrin. HCR are required for the centrosomal recruitment of MCPH proteins and centriolar duplication. Both HCR and astrin play key roles in keeping normal microtubule assembly and maintaining genomic stability.
中心体是调节微管组织和细胞有丝分裂进程的最重要的非膜细胞器之一。卷曲螺旋α-螺旋结构域蛋白 1（CCHCR1，也称为 HCR）基因被认为是银屑病易感基因，该蛋白被认为定位于哺乳动物细胞的 P 体和中心体。然而，HCR 的确切细胞功能及其在中心体中的潜在调节作用仍未被探索。
我们发现 HCR 与 astrin 直接相互作用，astrin 是中心体成熟和有丝分裂的关键因素。免疫沉淀实验表明，HCR 和 astrin 分别在其 C 端的卷曲螺旋区介导了它们之间的相互作用。astrin 不仅将 HCR 招募到中心体，还保护 HCR 免受泛素-蛋白酶体介导的降解。此外，敲低 HCR 或 astrin 均显著减少了 CEP72 和随后的 MCPH 蛋白（包括 CEP152、CDK5RAP2 和 CEP63）在中心体的定位。HCR 的缺失还导致中心体复制缺陷和有丝分裂错误，导致多极纺锤体形成、基因组不稳定性和 DNA 损伤。
我们得出结论，HCR 通过直接与 astrin 结合而被定位和稳定在中心体上。HCR 对于 MCPH 蛋白和中心体复制的中心体募集是必需的。HCR 和 astrin 均在维持正常微管组装和维持基因组稳定性方面发挥着关键作用。
