biostudies-literatureUnknown23(19)Monferran SThe Ku heterodimer (Ku70/Ku80) plays a central role in DNA double-strand breaks repair. Ku is also expressed on the cell surface of different types of cells where its function remains poorly understood. From a yeast two-hybrid screen, we have identified a specific interaction between the core region of Ku80 and the hemopexin domain of metalloproteinase 9 (MMP-9), a key enzyme involved in the degradation of extracellular matrix (ECM) components. Ku associates with MMP-9 on the surface of leukemic cells as demonstrated by co-immunoprecipitation experiments in membrane extracts and double-label immunofluorescence studies. In normal and tumoral migratory cells, Ku80 and MMP-9 colocalize at the periphery of leading edge of cells and cellular invasion of collagen IV matrices was blocked by antibThe EMBO journal3758-68https://www.ebi.ac.uk/biostudies/studies/S-EPMC522801biostudies-literatureThe membrane form of the DNA repair protein Ku interacts at the cell surface with metalloproteinase 9.PMC522801Paupert JSalles BMonferran SMuller CDauvillier SfalseThe membrane form of the DNA repair protein Ku interacts at the cell surface with metalloproteinase 9.The Ku heterodimer (Ku70/Ku80) plays a central role in DNA double-strand breaks repair. Ku is also expressed on the cell surface of different types of cells where its function remains poorly understood. From a yeast two-hybrid screen, we have identified a specific interaction between the core region of Ku80 and the hemopexin domain of metalloproteinase 9 (MMP-9), a key enzyme involved in the degradation of extracellular matrix (ECM) components. Ku associates with MMP-9 on the surface of leukemic cells as demonstrated by co-immunoprecipitation experiments in membrane extracts and double-label immunofluorescence studies. In normal and tumoral migratory cells, Ku80 and MMP-9 colocalize at the periphery of leading edge of cells and cellular invasion of collagen IV matrices was blocked by antib2004-01-01T00:00:00Z2004 Oct2025-05-31T23:06:29.586Z2025-05-31T23:06:29.586ZS-EPMC5228011538596110.1038/sj.emboj.7600403