K48-linked ubiquitination of TRAF3 further leads to its proteasome-dependent degradation. The resultant degradation of TRAF3 releases NIK from the cIAPs ubiquitin-ligase complex. NIK can escape from ubiquitination and subsequent degradation resulting in accumulation in the cytosol (Sas et al. 2012).
endopeptidase activity of 26S proteasome [cytosol]