title: Prointegrin maturation follows rapid trafficking and processing of MT1-MMP in Furin-Negative Colon Carcinoma LoVo Cells.
abstract: Understanding the function of invasion-promoting membrane type-1 matrix metalloproteinase (MT1-MMP) is of paramount importance for understanding cancer biology. MT1-MMP is synthesized in cells as a latent zymogen that requires the cleavage of its prodomain to exert the proteolytic activity. The mature alphav integrin subunit is also generated by endoproteolytic cleavage of the alphav subunit precursor (pro-alphav). Cleavage by furin is considered to be a principal event in the activation of both MT1-MMP and pro-alphav. To elucidate the alternative activation pathway of MT1-MMP and pro-alphav, we employed furin-negative LoVo cells, which co-express MT1-MMP with integrin alphavbeta3. In these cells the MT1-MMP proenzyme was rapidly trafficked to the plasma membrane via an unconventional Brefeldin A-resistant pathway and, then, autocatalytically processed on the cell surface. Next, the MT1-MMP activity converted the cell surface-associated pro-alphav into the mature alphav integrin, represented by the disulfide-bonded heavy and light chains, and promoted the formation of the functional integrin alphavbeta3 heterodimer. These events stimulated cell motility in vitro, and malignant invasion and tumor growth in vivo. Our data suggest that in furin-negative colon carcinoma cells MT1-MMP is autocatalytically processed and the active protease then operates as a prointegrin convertase. Our findings argue strongly that the processing by furin is not a prerequisite for the activation of MT1-MMP.
authors.affiliation: Cancer Research Center, the Burnham Institute, La Jolla, CA 92037, USA.
authors.forename: Elena I
authors.initials: EI
authors.lastname: Deryugina
authors.forename: Boris I
authors.initials: BI
authors.lastname: Ratnikov
authors.forename: Qing
authors.initials: Q
authors.lastname: Yu
authors.forename: Peter C
authors.initials: PC
authors.lastname: Baciu
authors.forename: Dmitri V
authors.initials: DV
authors.lastname: Rozanov
authors.forename: Alex Y
authors.initials: AY
authors.lastname: Strongin
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000378:metabolism; D016466:CHO Cells; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D003110:Colonic Neoplasms / Q000378:metabolism* / Q000473:pathology; D006224:Cricetinae; D004789:Enzyme Activation; D045683:Furin / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D053511:Matrix Metalloproteinase 14; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008817:Mice, Mutant Strains; D009361:Neoplasm Invasiveness; D009368:Neoplasm Transplantation; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology
chemical_list: D039302:Integrin alphaVbeta3; C507096:Mmp14 protein, mouse; D011498:Protein Precursors; D021122:Protein Subunits; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; D045683:Furin; D053504:Matrix Metalloproteinases, Membrane-Associated; D008666:Metalloendopeptidases; D020778:Matrix Metalloproteinase 2; D053511:Matrix Metalloproteinase 14