The 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 antibodies directed against Ku70 or Ku80 subunits as well as by Ku80-specific antisense oligonucleotides. Our results indicate that Ku and MMP-9 interact at the cell membrane of highly invasive hematopoietic cells of normal and tumoral origin and document the unexpected importance of the membrane-associated form of Ku in the regulation of ECM remodelling.
Monferran
Sylvie
S
Institut de Pharmacologie et de Biologie Structurale, CNRS UMR 5089, Toulouse, France.
Paupert
Jenny
J
Dauvillier
Stéphanie
S
Salles
Bernard
B
Muller
Catherine
C
D034961:Antigens, Nuclear / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement; D024141:Collagen Type IV / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006412:Hematopoietic Stem Cells / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D000072200:Ku Autoantigen; D007938:Leukemia / Q000378:metabolism / Q000473:pathology; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques
D034961:Antigens, Nuclear; D024141:Collagen Type IV; D004268:DNA-Binding Proteins; D016376:Oligonucleotides, Antisense; D020780:Matrix Metalloproteinase 9; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen