6xHis was fused on the N-terminus of the lysine 63 polyubiquitin chain binding domain of TAB2 encompassing amino acids 627-693. This fusion protein can be used for in vitro pulldown assays and for enrichment of cellular proteins conjugated with lysine 63 polyubiquitin chains in whole cell or tissue lysates. 6xHis-TAB2 (NZF) can be precipitated using Nickel resin. After washing, 6xHis-TAB2 (NZF) and its bound proteins can be eluted by a buffer containing 200 mM imidazole.