UBE2N/Ubc13: Proteins and Enzymes

Ubiquitin-conjugating Enzyme E2N (UBE2N), also known as Ubiquitin-conjugating Enzyme 13 (Ubc13), is a member of the Ubiquitin-conjugating (E2) enzyme family. UBE2N/Ubc13 has a predicted molecular weight of 17 kDa. The human enzyme shares 100% and 99% amino acid sequence identity with its mouse and rat orthologs, respectively. UBE2N/Ubc13 has an E2 catalytic core domain with an active site cysteine residue that is required for the formation of a thioester bond with Ubiquitin. UBE2N/Ubc13 localizes to both the nucleus and cytoplasm. UBE2N/Ubc13 forms heterodimeric complexes with Uev1a/UBE2V1 and Mms2, both of which are catalytically inactive E2 enzyme variants. The UBE2N (Ubc13)/Uev1A Complex is found in the cytoplasm and is important for inflammatory responses via Nuclear Factor kappa B (NF-kappa B) activation. In contrast, the UBE2N/Ubc13-Mms2 complex functions in the nucleus and is required for an efficient DNA damage response. Pathologically, UBE2N (Ubc13)/Uev1a Complex-mediated NF-kappa B activation is required for the proliferation of diffuse large B-cell lymphoma cells.