Schmidt Mirko H H, Dikic Ivan
Institute of Biochemistry II, Johann Wolfgang Goethe-University School of Medicine, Theodor-Stern-Kai 7, D-60590 Frankfurt, Germany.
Sci STKE. 2006 Nov 21;2006(362):.pe50. doi: 10.1126/stke.3622006pe50.
Ubiquitin (Ub) and ubiquitin-like (Ubl) proteins are small signaling molecules that are involved in many aspects of cell function. It has been assumed that Ub and Ubl have functionally distinct roles because they use different conjugation machineries and bind to different effector proteins. This paradigm, however, must be revisited after recent findings that signaling cascades mediated by Ub and the Ubl NEDD8 (Neural precursor cell-Expressed Developmentally Down-regulated 8) in the regulation of epidermal growth factor receptor (EGFR) endocytosis are redundant. In this context, Ub and NEDD8 share the same E3 ligase, Cbl, and are recognized by identical components of the endocytic sorting machinery. This unexpected redundancy introduces additional complexity to the current view of Ub signaling pathways.
泛素（Ub）和类泛素（Ubl）蛋白是参与细胞功能多个方面的小信号分子。人们一直认为Ub和Ubl具有不同的功能作用，因为它们使用不同的缀合机制并结合不同的效应蛋白。然而，最近发现Ub和类泛素NEDD8（神经前体细胞表达的发育下调8）介导的信号级联在表皮生长因子受体（EGFR）内吞作用的调节中是冗余的，这一范式必须重新审视。在这种情况下，Ub和NEDD8共享相同的E3连接酶Cbl，并被内吞分选机制的相同组分识别。这种意外的冗余给当前Ub信号通路的观点带来了额外的复杂性。
