Heparinoids activate a protease, secreted by mucosa and tumors, via tethering supplemented by allostery.
Activation by glycosaminoglycans (GAGs) is an emerging trend among extracellular proteases important in disease. ProMMP-7, the zymogen of a matrix metalloproteinase secreted by mucosal epithelial and tumor cells, is activated at their surfaces by sulfated GAGs, but how? ProMMP-7 is activated in trans by representative heparin oligosaccharides in a length-dependent manner, with a large jump in activation at lengths of 16 monosaccharides. Imaging by atomic force microscopy visualized small complexes of proMMP-7 molecules linked by 8-mer lengths of heparinoids and extended assembles formed with 16-mer lengths of heparin. Complexes of proMMP-7 with polydisperse heparin or heparan sulfate were more diverse. Heparinoids evidently accelerate activation by tethering multiple proMMP-7 molecules together for proteolytic attack among neighbors. Removal of either the prodomain or C-terminal peptide sequence of KRSNSRKK from MMP-7 prevents formation of the long arrays induced by heparin 16-mers or heparan sulfate. The role of the C-terminus in activation assays suggests it contributes to remote, allosteric binding of GAGs. Enhancement of proteolytic velocity of MMP-by GAGs indicates them to be effectors of V-type allostery. GAGs from proteoglycans appear to assemble proMMP-7 molecules for activation, an event preceding its tumorigenic or antibacterial proteolytic activities at cell surfaces.
Department of Biochemistry and ‡Department of Physics and Astronomy, University of Missouri , Columbia, Missouri 65211, United States.
Yan G
YG
Fulcher
Raghavendar Reddy
RR
Sanganna Gari
Nathan C
NC
Frey
Fuming
F
Zhang
Robert J
RJ
Linhardt
Gavin M
GM
King
Steven R
SR
Van Doren
D000494:Allosteric Regulation; D000818:Animals; D004789:Enzyme Activation; D006496:Heparinoids / Q000494:pharmacology*; D006801:Humans; D020783:Matrix Metalloproteinase 7 / Q000235:genetics / Q000378:metabolism; D018625:Microscopy, Atomic Force; D008954:Models, Biological; D009092:Mucous Membrane / Q000378:metabolism*; D009369:Neoplasms / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats; D013499:Surface Properties
D006496:Heparinoids; D010447:Peptide Hydrolases; D020783:Matrix Metalloproteinase 7