Systematic identification and analysis of mammalian small ubiquitin-like modifier substrates
Systematic identification and analysis of mammalian small ubiquitin-like modifier substrates
复制标题
DOI：
10.1074/jbc.m411718200
复制
发表时间：
2005-02-11
影响因子：
4.8
通讯作者：
Kang, JS
中科院分区：
文献类型：
--
作者：
Gocke, CB;Yu, HT;Kang, JS
小泛素样修饰剂 (SUMO) 通过与靶蛋白的可逆共价连接来调节多种细胞过程。许多 SUMO 底物参与转录和染色质结构。苏酰化似乎通过改变靶蛋白的亚细胞定位、增加其稳定性和/或介导其与其他蛋白的结合来调节靶蛋白的功能。使用体外表达克隆方法，我们鉴定了 40 种人类 SUMO1 底物。我们筛选中鉴定的人类 SUMO1 底物谱表明了 sumoylation 在转录、染色体结构和 RNA 加工中的一般作用。我们已经验证了活细胞中 24 种底物的苏酰化。对这组 SUMO 底物的分析得出以下观察结果。 1）苏酰化在体外比在活细胞中更有效。多聚苏酰化发生在体外的几种底物上。 2) SUMO肽酶几乎没有底物特异性。 3) SUMO 连接酶 PIAS1 和 PIASxbeta 比 PIASy 具有更广泛的底物特异性。 4) 尽管 SUMO1 和 SUMO2 在体外与给定底物的缀合效率相同，但 SUMO1 在体内缀合效率更高。 5）大多数SUMO底物定位于细胞核，并且SUMO化通常不会影响它们的亚细胞定位。因此，SUMO化似乎通过多种上下文相关机制来调节其底物的功能。
Small ubiquitin-like modifier (SUMO) regulates diverse cellular processes through its reversible, covalent attachment to target proteins. Many SUMO substrates are involved in transcription and chromatin structure. Sumoylation appears to regulate the functions of target proteins by changing their subcellular localization, increasing their stability, and/or mediating their binding to other proteins. Using an in vitro expression cloning approach, we have identified 40 human SUMO1 substrates. The spectrum of human SUMO1 substrates identified in our screen suggests general roles of sumoylation in transcription, chromosome structure, and RNA processing. We have validated the sumoylation of 24 substrates in living cells. Analysis of this panel of SUMO substrates leads to the following observations. 1) Sumoylation is more efficient in vitro than in living cells. Polysumoylation occurs on several substrates in vitro. 2) SUMO isopeptidases have little substrate specificity. 3) The SUMO ligases, PIAS1 and PIASxbeta, have broader substrate specificities than does PIASy. 4) Although SUMO1 and SUMO2 are equally efficiently conjugated to a given substrate in vitro, SUMO1 conjugation is more efficient in vivo. 5) Most SUMO substrates localize to the nucleus, and sumoylation does not generally affect their subcellular localization. Therefore, sumoylation appears to regulate the functions of its substrates through multiple, context-dependent mechanisms.