The function of TAB3 (TGF-beta activated kinase 1 (MAP3K7) binding protein 3, Ensembl gene identifier ENSG00000157625) is as follows. Adapter required to activate the JNK and NF-kappa-B signaling pathways through the specific recognition of 'Lys-63'-linked polyubiquitin chains by its RanBP2-type zinc finger (NZF) (PubMed:14633987, PubMed:14766965, PubMed:15327770, PubMed:22158122). Acts as an adapter linking MAP3K7/TAK1 and TRAF6 to 'Lys-63'-linked polyubiquitin chains (PubMed:14633987, PubMed:14766965, PubMed:15327770, PubMed:22158122, PubMed:36593296). The RanBP2-type zinc finger (NZF) specifically recognizes Lys-63'-linked polyubiquitin chains unanchored or anchored to the substrate proteins such as RIPK1/RIP1 and RIPK2: this acts as a scaffold to organize a large signaling complex to promote autophosphorylation of MAP3K7/TAK1, and subsequent activation of I-kappa-B-kinase (IKK) core complex by MAP3K7/TAK1 (PubMed:15327770, PubMed:18079694, PubMed:22158122). {ECO:0000269|PubMed:14633987, ECO:0000269|PubMed:14766965, ECO:0000269|PubMed:15327770, ECO:0000269|PubMed:18079694, ECO:0000269|PubMed:22158122, ECO:0000269|PubMed:36593296}. [Isoform 2]: May be an oncogenic factor. .