Intermolecular autolytic cleavage can contribute to the activation of progelatinase A by cell membranes.
Membrane-type matrix metalloproteinase (MT-MMP) messenger RNA and protein expression were shown to be elevated in human fibroblasts following treatment with concanavalin A, coincident with the induction of the ability to process progelatinase A. CHO cells transfected with the cDNA for MT-MMP were able to process both wild type progelatinase A and a catalytically inactive mutant, E375A progelatinase A. Both proenzymes were converted to a 68-kDa intermediate (reducing gels) form, but only the wild type enzyme was processed further to a 66-kDa end product. In contrast, both forms of progelatinase were processed via the 68-kDa intermediate to 66 kDa by concanavalin A-stimulated fibroblasts. Further study of the processing of E375A progelatinase A by plasma membrane preparations from concanavalin A-stimulated fibroblasts showed that addition of active gelatinase A enhanced processing to the mature form. It was concluded that cell membrane-mediated activation of progelatinase A could be via a cascade involving both MT-MMP and intermolecular autolytic cleavage.
Department of Cell and Molecular Biology, Strangeways Research Laboratory, Cambridge, United Kingdom.
S J
SJ
Atkinson
T
T
Crabbe
S
S
Cowell
R V
RV
Ward
M J
MJ
Butler
H
H
Sato
M
M
Seiki
J J
JJ
Reynolds
G
G
Murphy
D003208:Concanavalin A / Q000494:pharmacology; D004789:Enzyme Activation; D004790:Enzyme Induction; D004792:Enzyme Precursors / Q000096:biosynthesis / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000201:enzymology; D018093:Gelatinases / Q000096:biosynthesis / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008666:Metalloendopeptidases / Q000096:biosynthesis / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D017354:Point Mutation; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2; D019714:Tissue Inhibitor of Metalloproteinases
D004792:Enzyme Precursors; D006023:Glycoproteins; D011506:Proteins; D011994:Recombinant Proteins; D019714:Tissue Inhibitor of Metalloproteinases; D003208:Concanavalin A; D019716:Tissue Inhibitor of Metalloproteinase-2; D018093:Gelatinases; D008666:Metalloendopeptidases; C069860:progelatinase