TAB3 (TGF-beta activated kinase 1/MAP3K7 binding protein 3) has CUE domain and RanBP2-type zinc finger (NZF) domains mediates binding to two consecutive 'Lys-63'-linked ubiquitins. It contains 712 amino acids. TAB3 is a mediator of MAP3K7 activation and it forms a ternary complex with the protein kinase MAP3K7/TAK1 and either TRAF2 or TRAF6 in response to stimulation of TNF or IL-1. This successive MAP3K7/TAK1 kinase activity triggers a signaling cascade leading to activation of the NF-kappaB transcription factor and AP1 transcription factor. This protein shows interaction with TAB1, TAB2, MAP3K7, TRAF2 and TRAF6. It has 2 isoforms produced by alternative splicing. Isoform 2 may be an oncogenic factor. TAB3 involved in necrosis and tumors like disease.