Non-catalytic component of a structure-specific DNA repair endonuclease responsible for the 5'-incision during DNA repair. Responsible, in conjunction with SLX4, for the first step in the repair of interstrand cross-links (ICL). Participates in the processing of anaphase bridge-generating DNA structures, which consist in incompletely processed DNA lesions arising during S or G2 phase, and can result in cytokinesis failure. Also required for homology-directed repair (HDR) of DNA double-strand breaks, in conjunction with SLX4. Not functional in the nucleotide excision repair pathway. Not functional in the nucleotide excision repair pathway. Not functional in the nucleotide excision repair pathway. Heterodimer composed of ERCC1 isoform 1 and ERCC4/XPF (PubMed:16076955, PubMed:16338413, PubMed:24036546, PubMed:25538220, PubMed:32034146). Interacts with USP45 (PubMed:25538220). Does not interact with ERCC4/XPF. Does not interact with ERCC4/XPF. Does not interact with ERCC4/XPF. Ubiquitinated with both 'Lys-48' and 'Lys-63' linkages (PubMed:25538220). Deubiquitinated by USP45 (PubMed:25538220). The disease is caused by variants affecting the gene represented in this entry. Belongs to the ERCC1/RAD10/SWI10 family.