RAP80 has a key role in the recruitment of the Abraxas–BRCC36–BRCA1–BARD1 complex
to DNA‐damage foci for DNA repair through specific recognition of Lys 63‐linked
polyubiquitinated proteins by its tandem ubiquitin‐interacting motifs (UIMs). Here, we report
the crystal structure of the RAP80 tandem UIMs (RAP80‐UIM1‐UIM2) in complex with Lys
63‐linked di‐ubiquitin at 2.2 Å resolution. The two UIMs, UIM1 and UIM2, and the α‐helical
inter‐UIM region together form a continuous 60 Å‐long α‐helix. UIM1 and UIM2 bind to the …

TAB2 and TAB3 activate the Jun N‐terminal kinase and nuclear factor‐κB 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 Å 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 …