The biological function of NACAD remains unknown, but it shows high sequence similarity to the nascent polypeptide-associated complex (NAC) subunit alpha (NACA) that exists as part of several protein complexes playing a role in proliferation, apoptosis, or degradation. Like NACA, NACAD contains an NAC domain and a C-terminal ubiquitin-associated (UBA)-like domain. This entry represents the UBA-like domain of NACAD.