Kristariyanto Yosua Adi, Abdul Rehman Syed Arif, Campbell David G, Morrice Nicholas A, Johnson Clare, Toth Rachel, Kulathu Yogesh
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
Mol Cell. 2015 Apr 2;58(1):83-94. doi: 10.1016/j.molcel.2015.01.041. Epub 2015 Mar 5.
Polyubiquitin chains regulate diverse cellular processes through the ability of ubiquitin to form chains of eight different linkage types. Although detected in yeast and mammals, little is known about K29-linked polyubiquitin. Here we report the generation of K29 chains in vitro using a ubiquitin chain-editing complex consisting of the HECT E3 ligase UBE3C and the deubiquitinase vOTU. We determined the crystal structure of K29-linked diubiquitin, which adopts an extended conformation with the hydrophobic patches on both ubiquitin moieties exposed and available for binding. Indeed, the crystal structure of the NZF1 domain of TRABID in complex with K29 chains reveals a binding mode that involves the hydrophobic patch on only one of the ubiquitin moieties and exploits the flexibility of K29 chains to achieve linkage selective binding. Further, we establish methods to study K29-linked polyubiquitin and find that K29 linkages exist in cells within mixed or branched chains containing other linkages.
多聚泛素链通过泛素形成八种不同连接类型链的能力来调节多种细胞过程。尽管在酵母和哺乳动物中已检测到，但关于K29连接的多聚泛素却知之甚少。在此，我们报道了使用由HECT E3连接酶UBE3C和去泛素化酶vOTU组成的泛素链编辑复合物在体外生成K29链。我们确定了K29连接的双泛素的晶体结构，其采用一种伸展构象，两个泛素部分上的疏水补丁暴露且可用于结合。实际上，TRABID的NZF1结构域与K29链复合物的晶体结构揭示了一种结合模式，该模式仅涉及其中一个泛素部分上的疏水补丁，并利用K29链的灵活性实现连接选择性结合。此外，我们建立了研究K29连接的多聚泛素的方法，并发现K29连接存在于含有其他连接的混合或分支链的细胞中。
