Equilibrina I, Matsunaga S, Morimoto A, Hashimoto T, Uchiyama S, Fukui K
Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Japan.
Cytogenet Genome Res. 2013;139(4):225-33. doi: 10.1159/000350004. Epub 2013 Mar 23.
Sister chromatid cohesion mediated by the cohesin complex is essential for faithful chromosome segregation. Previously we reported that PHB2 (prohibitin2/ASURA), a multifunctional protein, has a role in sister chromatid cohesion. Nevertheless, how ASURA is involved in sister chromatid cohesion still remains unclear. The present co-immunoprecipitation analysis reveals that ASURA interacts with cohesin subunit Scc1 in vivo. We show that ASURA associates with chromatin in a similar manner as Scc1 throughout the cell cycle. Furthermore, our observation using the Fucci (fluorescent ubiquitination-based cell cycle indicator) system indicates that ASURA is important for cohesin maintenance at early mitosis. We have also identified that the conserved PHB domain is responsible for chromatin targeting of ASURA. Our results suggest that the regulation of sister chromatid cohesion is mediated by ASURA binding to chromatin, where ASURA might be involved in cohesin protection through ASURA-Scc1 interactions.
由黏连蛋白复合体介导的姐妹染色单体黏连对于准确的染色体分离至关重要。此前我们报道过，多功能蛋白PHB2（抑制素2/阿苏拉蛋白）在姐妹染色单体黏连中发挥作用。然而，阿苏拉蛋白如何参与姐妹染色单体黏连仍不清楚。目前的免疫共沉淀分析显示，阿苏拉蛋白在体内与黏连蛋白亚基Scc1相互作用。我们发现，在整个细胞周期中，阿苏拉蛋白与染色质的结合方式与Scc1相似。此外，我们使用Fucci（基于荧光泛素化的细胞周期指示剂）系统的观察结果表明，阿苏拉蛋白对于有丝分裂早期黏连蛋白的维持很重要。我们还确定，保守的PHB结构域负责阿苏拉蛋白的染色质靶向。我们的结果表明，姐妹染色单体黏连的调节是由阿苏拉蛋白与染色质的结合介导的，在这一过程中，阿苏拉蛋白可能通过阿苏拉蛋白-Scc1相互作用参与黏连蛋白的保护。
