Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal, 645, 08028 Barcelona, Spain.
Biochem Soc Trans. 2010 Feb;38(Pt 1):34-9. doi: 10.1042/BST0380034.
One of the more rapidly expanding fields in cell signalling nowadays is the characterization of proteins conjugated to Ub (ubiquitin) or Ub-like peptides, such as SUMO (small Ub-related modifier). The reversible covalent attachment of these small peptides remodels the target protein, providing new protein-protein interaction interfaces, which can be dynamically regulated given a set of enzymes for conjugation and deconjugation. First, ubiquitination was thought to be merely relegated to the control of protein turnover and degradation, whereas the attachment of SUMO was involved in the regulation of protein activity and function. However, the boundaries between the protein fates related to these tag molecules are becoming more and more fuzzy, as either the differences between mono-, multi- and poly-modifications or the lysine residue used for growth of the poly-chains is being dissected. The Ub and SUMO pathways are no longer separated, and many examples of this cross-talk are found in the literature, involving different cellular processes ranging from DNA repair and genome stability, to the regulation of protein subcellular localization or enzyme activity. Here, we review several cases in which SUMOylation and ubiquitination intersect, showing also that the same protein can be conjugated to SUMO and Ub for antagonistic, synergistic or multiple outcomes, illustrating the intricacy of the cellular signalling networks. Ub and SUMO have met and are now applying for new regulatory roles in the cell.
如今，细胞信号转导领域中发展最为迅速的领域之一是对与 Ub（泛素）或 Ub 样肽（如 SUMO（小泛素相关修饰物））缀合的蛋白质进行特征描述。这些小肽的可逆共价连接重塑了靶蛋白，提供了新的蛋白质-蛋白质相互作用界面，这些界面可以通过一组用于缀合和去缀合的酶进行动态调节。最初，泛素化被认为仅局限于控制蛋白质周转和降解，而 SUMO 的附着则参与了蛋白质活性和功能的调节。然而，与这些标记分子相关的蛋白质命运之间的界限变得越来越模糊，因为无论是单、多和多聚修饰之间的差异，还是用于多链生长的赖氨酸残基，都在被剖析。Ub 和 SUMO 途径不再分离，并且在文献中发现了许多这种串扰的例子，涉及从 DNA 修复和基因组稳定性到蛋白质亚细胞定位或酶活性的调节等不同的细胞过程。在这里，我们回顾了几个 SUMO 化和泛素化相互交叉的例子，还表明同一蛋白质可以同时被 SUMO 和 Ub 缀合，以产生拮抗、协同或多种结果，说明了细胞信号网络的复杂性。Ub 和 SUMO 已经相遇，并正在细胞中申请新的调节作用。
