Background：Negative regulator of the non-canonical NF-kappa-B pathway that acts by mediating deubiquitination of TRAF3, an inhibitor of the NF-kappa-B pathway, thereby acting as a negative regulator of B-cell responses. In response to non-canonical NF-kappa-B stimuli, deubiquitinates 'Lys-48'-linked polyubiquitin chains of TRAF3, preventing TRAF3 proteolysis and over-activation of non-canonical NF-kappa-B. Negatively regulates mucosal immunity against infections. Mediates deubiquitination of EGFR. Has deubiquitinating activity toward 'Lys-11', 'Lys-48' or 'Lys-63'-linked polyubiquitin chains. In vitro, has preference for 'Lys-11'-linked polyubiquitin chains; however such data are unsure in vivo. Hydrolyzes both linear and branched forms of polyubiquitin.
