UFD1L is a member of the UFD1 family of proteins and is a component of the ubiquitin-dependent proteolytic pathway which degrades ubiquitin fusion proteins. This complex, also containing UFD1L, VCP and NPLOC4, binds ubiquitinated proteins and is required for the export of misfolded proteins from the ER to the cytoplasm for disposal. The NPLOC4-UFD1L-VCP complex also regulates spindle disassembly at the end of mitosis and is necessary for the formation of a closed nuclear envelope. UFD1L gene hemizygosity is the cause of some developmental defects including DiGeorge syndrome (DGS), velo-cardio-facial syndrome (VCFS) and Opitz G/BBB syndrome. UFD1L has 2 named isoforms produced by alternative splicing.