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Publication Abstract from PubMed

TAB2 and TAB3 activate the Jun N-terminal kinase and nuclear factor-kappaB pathways through the specific recognition of Lys 63-linked polyubiquitin chains by its Npl4 zinc-finger (NZF) domain. Here we report crystal structures of the TAB2 and TAB3 NZF domains in complex with Lys 63-linked diubiquitin at 1.18 and 1.40 A resolutions, respectively. Both NZF domains bind to the distal ubiquitin through a conserved Thr-Phe dipeptide that has been shown to be important for the interaction of the NZF domain of Npl4 with monoubiquitin. In contrast, a surface specific to TAB2 and TAB3 binds the proximal ubiquitin. Both the distal and proximal binding sites of the TAB2 and TAB3 NZF domains recognize the Ile 44-centred hydrophobic patch on ubiquitin but do not interact with the Lys 63-linked isopeptide bond. Mutagenesis experiments show that both binding sites are required to enable binding of Lys 63-linked diubiquitin. We therefore propose a mechanism for the recognition of Lys 63-linked polyubiquitin chains by TAB2 and TAB3 NZF domains in which diubiquitin units are specifically recognized by a single NZF domain.

Structural basis for specific recognition of Lys 63-linked polyubiquitin chains by NZF domains of TAB2 and TAB3.,Sato Y, Yoshikawa A, Yamashita M, Yamagata A, Fukai S EMBO J. 2009 Dec 16;28(24):3903-9. Epub . PMID:19927120^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.