Non-catalytic subunit of the structure-specific, heterodimeric DNA endonuclease MUS81-EME1 which is involved in the maintenance of genome stability. In the complex, EME1 is required for DNA cleavage, participating in DNA recognition and bending (PubMed:12686547, PubMed:12721304, PubMed:14617801, PubMed:17289582, PubMed:24733841, PubMed:24813886, PubMed:35290797, PubMed:39015284). MUS81-EME1 cleaves 3'-flaps and nicked Holliday junctions, and exhibit limited endonuclease activity with 5' flaps and nicked double-stranded DNAs (PubMed:24733841, PubMed:35290797). Active during prometaphase, MUS81-EME1 resolves mitotic recombination intermediates, including Holliday junctions, which form during homologous recombination (PubMed:14617801, PubMed:24813886). {ECO:0000269|PubMed:12686547, ECO:0000269|PubMed:12721304, ECO:0000269|PubMed:14617801, ECO:0000269|PubMed:17289582, ECO:0000269|PubMed:24733841, ECO:0000269|PubMed:24813886, ECO:0000269|PubMed:35290797, ECO:0000269|PubMed:39015284}. This is the function of ENSG00000154920 (EME1, essential meiotic structure-specific endonuclease 1).