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Regulatory mechanism of matrix metalloproteinase activity.

基质金属蛋白酶活性的调节机制。

基本信息

批准号：
04680169
负责人：
MIYAZAKI Kaoru
金额：
$ 1.28万
依托单位：
Yokohama City University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Matrix metalloproteinases (MMPs) are involved in various physiological and pathological conditions including arthritis and tumor metastasis. The activity of MMPs are regulated by three mechanisms : regulation of synthesis, activation of their latent proenzymes, and regulation of active enzymes by natural inhibitors. Proenzymes of most MMPs are known to be activated by some serine proteinases, whereas only the activating enzymes of pro-gelatinase A remain unknown. The present study aimed to clarify the natural activators of pro-gelatinase A.Pro-gelatinase A was purified in TIMP-2 bound and -free forms from conditioned medium of T98G human glioblastoma cell line. The TIMP-2-free pro-gelatinase A of 64 kDa (apparent molecular size under nonreducing conditions) was rapidly activated to the 57-kDa and then the 41-kDa mature forms by treatment with p-aminophenylmercuric acetate (APMA). When the TIMP-2-free form was incubated with stromelysin, a member of MMP family, its gelatinolytic activity increased to about 70% of the activity obtained by APMA activation, forming the 41-kDa form. The treatment of the TIMP-2-bound pro-gelatinase A with stromelysin also increased its gelatinolytic activity but hardly produced any mature forms. Analysis of interaction of the TIMP-2-bound proenzyme and stromelysin demonstrated that stromelysin bound to the TIMP-2 molecule in the TIMP-2/pro-gelatinase A complex, forming a tertiary protein complex with a significant gelatinolytic activity. These results suggest that stromelysin may function as a natural activator of pro-gelatinase A under some conditions.

基质金属蛋白酶（Matrix metalloproteinases，MMPs）参与关节炎、肿瘤转移等多种生理和病理过程。MMPs的活性受三种机制的调节：合成的调节、其潜在酶原的激活以及天然抑制剂对活性酶的调节。大多数基质金属蛋白酶的酶原已知被一些丝氨酸蛋白酶激活，而只有明胶酶原A的激活酶仍然未知。本研究的目的是澄清明胶酶前体A的天然激活剂。明胶酶前体A是从T98 G人胶质母细胞瘤细胞系的条件培养基中纯化的TIMP-2结合和游离形式。TIMP-2-免费的前明胶酶A的64 kDa（表观分子大小在非还原条件下）被迅速激活为57 kDa，然后41 kDa的成熟形式，通过处理与对氨基苯汞乙酸（APMA）。当不含TIMP-2的形式与基质分解素（MMP家族成员）一起孵育时，其明胶分解活性增加至APMA活化获得的活性的约70%，形成41-kDa形式。用溶基质素处理TIMP-2结合的前明胶酶A也增加了其明胶分解活性，但几乎不产生任何成熟形式。TIMP-2结合的酶原和基质分解素的相互作用的分析表明，基质分解素结合到TIMP-2/前明胶酶A复合物中的TIMP-2分子，形成具有显著明胶分解活性的三级蛋白复合物。这些结果表明，在某些条件下，溶基质素可能作为明胶酶A原的天然激活剂。