Non-catalytic component of the KPC complex, a E3 ubiquitin-protein ligase complex that mediates polyubiquitination of target proteins, such as CDKN1B and NFKB1 ( , ). The KPC complex catalyzes polyubiquitination and proteasome-mediated degradation of CDKN1B during G1 phase of the cell cycle (, ). The KPC complex also acts as a key regulator of the NF-kappa-B signaling by promoting maturation of the NFKB1 component of NF-kappa-B by catalyzing ubiquitination of the NFKB1 p105 precursor . Within the KPC complex, UBAC1 acts as an adapter that promotes the transfer of target proteins that have been polyubiquitinated by RNF123/KPC1 to the 26S proteasome .
Subcellular locations: Cytoplasm
Ubiquitous.