Montreal Neurological Institute, McGill University, room MP038, 3801 University, Montreal, Quebec, H3A 2B4, Canada.
Curr Opin Struct Biol. 2011 Dec;21(6):792-801. doi: 10.1016/j.sbi.2011.09.009. Epub 2011 Oct 27.
Polyubiquitin chains are assembled through the formation of an isopeptide bond between a lysine side-chain or terminal amino group of a proximal ubiquitin moiety and the carboxy-terminal of a distal ubiquitin moiety. Protein substrates tagged by polyubiquitin chains of different linkages undergo different fates. Many polyubiquitin chain types have been characterized so far, notably Lys11, Lys48, Lys63 and linear chains. These different types of chains are synthesized, disassembled and recognized by selective enzymes and receptors. Here I survey the structural basis for the selective binding of polyubiquitin chains of specific linkages, with an emphasis on recent advances in our understanding of polyubiquitin chain structure and functions. Recent work suggests linkage-type discrimination by members of the NF-κb signalling and DNA repair pathways and a specific role for Lys48-linked polyubiquitin chain recognition by proteasome-associated proteins.
多聚泛素链通过赖氨酸侧链或近端泛素部分的末端氨基与远端泛素部分的羧基末端之间形成异肽键而组装。被多聚泛素链不同连接标记的蛋白质底物经历不同的命运。迄今为止，已经鉴定出许多多聚泛素链类型，特别是 Lys11、Lys48、Lys63 和线性链。这些不同类型的链由选择性酶和受体合成、拆卸和识别。在这里，我调查了特异性连接的多聚泛素链选择性结合的结构基础，重点介绍了我们对多聚泛素链结构和功能的理解的最新进展。最近的工作表明，NF-κb 信号转导和 DNA 修复途径的成员对连接类型具有鉴别能力，并且蛋白酶体相关蛋白对 Lys48 连接的多聚泛素链的识别具有特定作用。
