Necessary for the fragmentation of Golgi stacks during mitosis and for their reassembly after mitosis. Involved in the formation of the transitional endoplasmic reticulum (tER). The transfer of membranes from the endoplasmic reticulum to the Golgi apparatus occurs via 50-70 nm transition vesicles which derive from part-rough, part-smooth transitional elements of the endoplasmic reticulum (tER). Vesicle budding from the tER is an ATP-dependent process. The ternary complex containing UFD1L, VCP and NPLOC4 binds ubiquitinated proteins and is necessary for the export of misfolded proteins from the ER to the cytoplasm, where they are degraded by the proteasome. The NPLOC4-UFD1L-VCP complex regulates spindle disassembly at the end of mitosis and is necessary for the formation of a closed nuclear envelope. Regulates E3 ubiquitin-protein ligase activity of RNF19A (By similarity). Component of the VCP/p97-AMFR/gp78 complex that participates in the final step of the sterol-mediated ubiquitination and endoplasmic reticulum-associated degradation (ERAD) of HMGCR. Also involved in DNA damage response: recruited to double-strand breaks (DSBs) sites in a RNF8-and RNF168-dependent manner and promotes the recruitment of TP53BP1 at DNA damage sites. Recruited to stalled replication forks by SPRTN: may act by mediating extraction of DNA polymerase eta (POLH) to prevent excessive translesion DNA synthesis and limit the incidence of mutations induced by DNA damage.

• GO:0006919 : activation of cysteine-type endopeptidase activity involved in apoptotic process
• GO:0070842 : aggresome assembly
• GO:0006302 : double-strand break repair
• GO:0030968 : endoplasmic reticulum unfolded protein response
• GO:0006888 : ER to Golgi vesicle-mediated transport
• GO:0030433 : ER-associated protein catabolic process
• GO:0032436 : positive regulation of proteasomal ubiquitin-dependent protein catabolic process
• GO:0031334 : positive regulation of protein complex assembly
• GO:0051260 : protein homooligomerization
• GO:0018279 : protein N-linked glycosylation via asparagine
• GO:0016567 : protein ubiquitination
• GO:0030970 : retrograde protein transport, ER to cytosol
• GO:0019985 : translesion synthesis

Source: The Gene Ontology Consortium. Gene ontology: tool for the unification of biology. Nat. Genet.. May 2000;25(1):25-9.
World Wide Web URL: http://www.geneontology.org/

• OMIM:601023 : Inclusion body myopathy with early-onset Paget disease and frontotemporal dementia (OMIM:167320 )
• OMIM:601023 : Amyotrophic lateral sclerosis 14 with or without frontotemporal dementia (OMIM:613954 )

Source: Online Mendelian Inheritance in Man, OMIM®. McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University (Baltimore, MD), May, 2012.
World Wide Web URL: http://omim.org/