RING finger protein 31 is a protein that in humans is encoded by the RNF31 gene.

The protein encoded by this gene contains a RING finger, a motif present in a variety of functionally distinct proteins and known to be involved in protein-DNA and protein-protein interactions. [provided by RefSeq, Jul 2008].
Function: Component of the LUBAC complex which conjugates linear polyubiquitin chains in a head-to-tail manner to substrates. LUBAC conjugates linear polyubiquitin to IKBKG at 'Lys-285' and 'Lys-309' and is involved in activation of the canonical NF-kappa-B and the JNK signaling pathways. LUBAC is proposed to be 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. Binds polyubiquitin of different linkage types.