title: Intracellular and cell surface localization of a complex between alphaMbeta2 integrin and promatrix metalloproteinase-9 progelatinase in neutrophils.
abstract: We have recently demonstrated that promatrix metalloproteinases (proMMPs), particularly proMMP-9, are potent ligands of the leukocyte beta(2) integrins. We studied here the complex formation between proMMP-9 and alpha(M)beta(2), the major MMP and integrin of neutrophils. On resting neutrophils, the proMMP-9/alpha(M)beta(2) complex was primarily detected in intracellular granules, but after cellular activation it became localized to the cell surface, as demonstrated by immunoprecipitation and double immunofluorescence. Further indication of the complex formation was that neutrophils and alpha(M)beta(2)-transfected L cells, but not the wild-type L cells or leukocyte adhesion deficiency cells, bound to immobilized proMMP-9 or its recombinant catalytic domain in a beta(2) integrin-dependent manner. Peptides that bound to the alpha(M) integrin-I domain and inhibited its complex formation with proMMP-9 prevented neutrophil migration in a transendothelial assay in vitro and in a thioglycolate-elicited peritonitis in vivo. These results suggest that the translocating proMMP-9/alpha(M)beta(2) complex may be part of the cell surface machinery guiding neutrophil migration.
authors.affiliation: Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland. stefanid@mappi.helsinki.fi
authors.forename: Michael
authors.initials: M
authors.lastname: Stefanidakis
authors.forename: Terhi
authors.initials: T
authors.lastname: Ruohtula
authors.forename: Niels
authors.initials: N
authors.lastname: Borregaard
authors.forename: Carl G
authors.initials: CG
authors.lastname: Gahmberg
authors.forename: Erkki
authors.initials: E
authors.lastname: Koivunen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002465:Cell Movement; D017364:Collagenases / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism*; D006801:Humans; D016177:Macrophage-1 Antigen / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D004792:Enzyme Precursors; D016177:Macrophage-1 Antigen; D017364:Collagenases; C120487:pro-matrix metalloproteinase 9; D020780:Matrix Metalloproteinase 9