Mechanisms of activation of tissue procollagenase by matrix metalloproteinase 3 (stromelysin).
The mechanism of activation of tissue procollagenase by matrix metalloproteinase 3 (MMP-3)/stromelysin was investigated by kinetic and sequence analyses. MMP-3 slowly activated procollagenase by cleavage of the Gln80-Phe81 bond to generate a fully active collagenase of Mr = 41,000. The specific collagenolytic activity of this species was 27,000 units/mg (1 unit = 1 microgram of collagen digested in 1 min at 37 degrees C). Treatment of procollagenase with plasmin or plasma kallikrein gave intermediates of Mr = 46,000. These intermediates underwent rapid autolytic activation, via cleaving the Thr64-Leu65 bond, to give a collagenase species of Mr = 43,000 that exhibited only about 15% of the maximal specific activity. Similarly, (4-aminophenyl)mercuric acetate (APMA) activated procollagenase by intramolecular cleavage of the Val67-Met68 bond to generate a collagenase species of Mr = 43,000, but with only about 25% of the maximal specific activity. Subsequent incubation of the 43,000-Mr species with MMP-3 resulted in rapid, full activation and generated the 41,000-Mr collagenase by cleaving the Gln80-Phe81 bond. In the case of the proteinase-generated 43,000-Mr species, the action of MMP-3 was approximately 24,000 times faster than that on the native procollagenase. This indicates that the removal of a portion of the propeptide of procollagenase induces conformational changes around the Gln80-Phe81 bond, rendering it readily susceptible to MMP-3 activation. Prolonged treatment of procollagenase with APMA in the absence of MMP-3 also generated a 41,000-Mr collagenase, but this species had only 40% of the full activity and contained Val82 and Leu83 as NH2 termini. Thus, cleavage of the Gln80-Phe81 bond by MMP-3 is crucial for the expression of full collagenase activity. These results suggest that the activation of procollagenase by MMP-3 is regulated by two pathways: one with direct, slow activation by MMP-3 and the other with rapid activation in conjunction with tissue and/or plasma proteinases. The latter event may explain an accelerated degradation of collagens under certain physiological and pathological conditions.
Suzuki
K
K
Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City 66103.
Enghild
J J
JJ
Morodomi
T
T
Salvesen
G
G
Nagase
H
H
D000595:Amino Acid Sequence; D017364:Collagenases; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000378:metabolism*; D019278:Matrix Metalloproteinase 3; D008666:Metalloendopeptidases / Q000378:metabolism*; D003012:Microbial Collagenase / Q000378:metabolism*; D008969:Molecular Sequence Data
D004792:Enzyme Precursors; D017364:Collagenases; D008666:Metalloendopeptidases; C022440:procollagenase; D019278:Matrix Metalloproteinase 3; D003012:Microbial Collagenase