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Steps involved in activation of the complex of pro-matrix metalloproteinase 2 (progelatinase A) and tissue inhibitor of metalloproteinases (TIMP)-2 by 4-aminophenylmercuric acetate.

Abstract:
Tissue inhibitor of metalloproteinases (TIMP)-2 forms a noncovalent complex with the precursor of matrix metalloproteinase 2 (proMMP-2, progelatinase A) through interaction of the C-terminal domain of each molecule. We have isolated the proMMP-2-TIMP-2 complex from the medium of human uterine cervical fibroblasts and investigated the processes involved in its activation by 4-aminophenylmercuric acetate (APMA). The treatment of the complex with APMA-activated proMMP-2 by disrupting the Cys73-Zn2+ interaction of the zymogen. This is triggered by perturbation of the proMMP-2 molecule, but not by the reaction of the SH group of Cys73 with APMA. The 'activated' proMMP-2 (proMMP-2*) formed a new complex with TIMP-2 by binding to the N-terminal inhibitory domain of the inhibitor without processing the propeptide. Thus the APMA-treated proMMP-2*-TIMP-2 complex exhibited no gelatinolytic activity. In the presence of a small amount of free MMP-2, however, proMMP-2* in the complex was converted into the 65 kDa MMP-2 by proteolytic attack of MMP-2, but the complex did not exhibit gelatinolytic activity. The gelatinolytic activity detected after APMA treatment was solely derived from the activation of free proMMP-2. The removal of the propeptide of the proMMP-2* bound to TIMP-2 was also observed by MMP-3 (stromelysin 1), but not by MMP-1 (interstitial collagenase). MMP-3 cleaved the Asn80-Tyr81 bond of proMMP-2*. On the other hand, when MMP-3 was incubated with the proMMP-2-TIMP-2 complex, it bound to TIMP-2 and rendered proMMP-2 readily activatable by APMA. These results indicate that the blockage of TIMP-2 of the complex with an active MMP is essential for the activation of proMMP-2 when it is complexed with TIMP-2.

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Institution:
University of Oxford
Division:
MSD
Department:
NDORMS
Role:
Author


Journal:
Biochemical journal More from this journal
Volume:
308 ( Pt 2)
Pages:
645-651
Publication date:
1995-06-01
EISSN:
1470-8728
ISSN:
0264-6021


Language:
English
Keywords:
Pubs id:
pubs:411409
UUID:
uuid:0511450c-487e-4c52-b585-4b934cc551d6
Local pid:
pubs:411409
Source identifiers:
411409
Deposit date:
2014-02-14

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