This domain is present in ubiquitin-regulatory proteins and is a general Cdc48-interacting module [2].

1: The UBA domain: a sequence motif present in multiple enzyme classes of the ubiquitination pathway. Hofmann K, Bucher P; Trends Biochem Sci 1996;21:172-173. PMID:8871400

2: The Ubx2 and Ubx3 cofactors direct Cdc48 activity to proteolytic and nonproteolytic ubiquitin-dependent processes. Hartmann-Petersen R, Wallace M, Hofmann K, Koch G, Johnsen AH, Hendil KB, Gordon C; Curr Biol 2004;14:824-828. PMID:15120077