CAS-Max Planck Junior Scientist Group on Developmental Biology, State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 Jiaochang East Road, Kunming 650223, China.
Biochem Biophys Res Commun. 2010 Mar 19;393(4):708-13. doi: 10.1016/j.bbrc.2010.02.066. Epub 2010 Feb 17.
Modification of proteins by ubiquitination plays important roles in various cellular processes. During this process, the target specificity is determined by ubiquitin ligases. Here we identify RNF220 (RING finger protein 220) as a novel ubiquitin ligase for Sin3B. As a conserved RING protein, RNF220 can bind E2 and mediate auto-ubiquitination of itself. Through a yeast two-hybrid screen, we isolated Sin3B as one of its targets, which is a scaffold protein of the Sin3/HDAC (histone deacetylase) corepressor complex. RNF220 specifically interacts with Sin3B both in vitro and in vivo. Sin3B can be regulated by the ubiquitin-proteasome system. Co-expression of RNF220 promotes the ubiquitination and proteasomal degradation of Sin3B. Taken together, these results reveal a new mechanism for regulating the Sin3/HDAC complex.
泛素化修饰的蛋白质在各种细胞过程中发挥着重要作用。在这个过程中，泛素连接酶决定了靶蛋白的特异性。在这里，我们鉴定出 RNF220（环指蛋白 220）是 Sin3B 的一种新型泛素连接酶。作为一种保守的 RING 蛋白，RNF220 可以结合 E2 并介导自身的泛素化。通过酵母双杂交筛选，我们分离出 Sin3B 作为其靶蛋白之一，它是 Sin3/HDAC（组蛋白去乙酰化酶）核心抑制复合物的支架蛋白。RNF220 可在体外和体内与 Sin3B 特异性相互作用。Sin3B 可以被泛素-蛋白酶体系统调节。共表达 RNF220 可促进 Sin3B 的泛素化和蛋白酶体降解。综上所述，这些结果揭示了调节 Sin3/HDAC 复合物的一种新机制。
