E3 ubiquitin-protein ligase component of the LUBAC complex which conjugates linear ('Met-1'-linked) polyubiquitin chains to substrates and plays a key role in NF-kappa-B activation and regulation of inflammation (PubMed:17006537, PubMed:19136968, PubMed:20005846, PubMed:21455173, PubMed:21455180, PubMed:21455181, PubMed:22863777, PubMed:28189684, PubMed:28481331). LUBAC conjugates linear polyubiquitin to IKBKG and RIPK1 and is involved in activation of the canonical NF-kappa-B and the JNK signaling pathways (PubMed:17006537, PubMed:19136968, PubMed:20005846, PubMed:21455173, PubMed:21455180, PubMed:21455181, PubMed:22863777, PubMed:28189684). Linear ubiquitination mediated by the LUBAC complex interferes with TNF- induced cell death and thereby prevents inflammation (PubMed:21455173, PubMed:28189684). LUBAC is recruited to the TNF-R1 signaling complex (TNF-RSC) following polyubiquitination of TNF-RSC components by BIRC2 and/or BIRC3 and to conjugate linear polyubiquitin to IKBKG and possibly other components contributing to the stability of the complex (PubMed:20005846, PubMed:27458237). The LUBAC complex is also involved in innate immunity by conjugating linear polyubiquitin chains at the surface of bacteria invading the cytosol to form the ubiquitin coat surrounding bacteria (PubMed:28481331, PubMed:34012115). LUBAC is not able to initiate formation of the bacterial ubiquitin coat, and can only promote formation of linear polyubiquitins on pre-existing ubiquitin (PubMed:28481331). Recruited to the surface of bacteria by RNF213, which initiates the bacterial ubiquitin coat (PubMed:34012115). The bacterial ubiquitin coat acts as an 'eat-me' signal for xenophagy and promotes NF-kappa-B activation (PubMed:28481331, PubMed:34012115). Together with OTULIN, the LUBAC complex regulates the canonical Wnt signaling during angiogenesis (PubMed:23708998). RNF31 is required for linear ubiquitination of BCL10, thereby promoting TCR-induced NF-kappa- B activation (PubMed:27777308). Binds polyubiquitin of different linkage types (PubMed:23708998). {ECO:0000269|PubMed:17006537, ECO:0000269|PubMed:19136968, ECO:0000269|PubMed:20005846, ECO:0000269|PubMed:21455173, ECO:0000269|PubMed:21455180, ECO:0000269|PubMed:21455181, ECO:0000269|PubMed:22863777, ECO:0000269|PubMed:23708998, ECO:0000269|PubMed:27458237, ECO:0000269|PubMed:27777308, ECO:0000269|PubMed:28189684, ECO:0000269|PubMed:28481331, ECO:0000269|PubMed:34012115}. This is the function of Ensembl gene identifier ENSG00000092098 (RNF31, ring finger protein 31).