Binding of active (57 kDa) membrane type 1-matrix metalloproteinase (MT1-MMP) to tissue inhibitor of metalloproteinase (TIMP)-2 regulates MT1-MMP processing and pro-MMP-2 activation
Binding of active (57 kDa) membrane type 1-matrix metalloproteinase (MT1-MMP) to tissue inhibitor of metalloproteinase (TIMP)-2 regulates MT1-MMP processing and pro-MMP-2 activation
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DOI：
10.1074/jbc.275.16.12080
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发表时间：
2000-04-21
影响因子：
4.8
通讯作者：
Fridman, R
中科院分区：
文献类型：
--
作者：
Hernandez-Barrantes, S;Toth, M;Fridman, R
先前的研究表明，膜型1-基质金属蛋白酶（MT 1-MMP）（MMP-14）启动前MMP-2激活的过程中，是由金属蛋白酶组织抑制剂（TIMP）-2的水平密切调节。然而，考虑到调节TIMP-2水平的困难，TIMP-2在细胞系统中对MT 1-MMP加工和对pro-MMP-2活化的直接作用不能确定。在此，使用编码全长MT 1-MMP或TIMP-2的重组牛痘病毒在哺乳动物细胞中单独表达MT 1-MMP或与各种水平的TIMP-2组合表达MT 1-MMP。我们表明，TIMP-2调节细胞表面上的活性MT 1-MMP（57 kDa）的量，而在TIMP-2的情况下，MT 1-MMP经历自催化成44 kDa的形式，其显示N末端起始于Gly（285），因此缺乏整个催化结构域。pro-MT 1-MMP（N末端Ser（24））和44-kDa形式都不结合TIMP-2。相反，活性MT 1-MMP（N末端Tyr（112））与TIMP-2形成复合物，表明MT 1-MMP加工的调节由TIMP-2与活性酶的复合物介导。结论：TIMP-2可增强MT 1-MMP对pro-MMP-2的激活作用。因此，在受控条件下，TIMP-2可通过促进细胞表面上活性MT 1-MMP的可用性而充当MT 1-MMP活性的正调节剂，并且因此可支持细胞周围蛋白水解。
Previous studies have shown that membrane type 1-matrix metalloproteinase (MT1-MMP) (MMP-14) initiates pro-MMP-2 activation in a process that is tightly regulated by the level of tissue inhibitor of metalloproteinase (TIMP)-2. However, given the difficulty in modulating TIMP-2 levels, the direct effect of TIMP-2 on MT1-MMP processing and on pro-MMP-2 activation in a cellular system could not be established. Here, recombinant vaccinia viruses encoding full-length MT1-MMP or TIMP-2 were used to express MT1-MMP alone or in combination with various levels of TIMP-2 in mammalian cells. We show that TIMP-2 regulates the amount of active MT1-MMP (57 kDa) on the cell surface whereas in the absence of TIMP-2 MT1-MMP undergoes autocatalysis to a 44-kDa form, which displays a N terminus starting at Gly(285) and hence lacks the entire catalytic domain. Neither pro-MT1-MMP (N terminus Ser(24)) nor the 44-kDa form bound TIMP-2. In contrast, active MT1-MMP (N terminus Tyr(112)) formed a complex with TIMP-2 suggesting that regulation of MT1-MMP processing is mediated by a complex of TIMP-2 with the active enzyme. Consistently, TIMP-2 enhanced the activation of pro-MMP-2 by MT1-MMP. Thus, under controlled conditions, TIMP-2 may act as a positive regulator of MT1-MMP activity by promoting the availability of active MT1-MMP on the cell surface and consequently, may support pericellular proteolysis.