Atkinson S J, Crabbe T, Cowell S, Ward R V, Butler M J, Sato H, Seiki M, Reynolds J J, Murphy G
Department of Cell and Molecular Biology, Strangeways Research Laboratory, Cambridge, United Kingdom.
J Biol Chem. 1995 Dec 22;270(51):30479-85. doi: 10.1074/jbc.270.51.30479.
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.
在伴刀豆球蛋白A处理后的人成纤维细胞中，膜型基质金属蛋白酶（MT-MMP）信使核糖核酸和蛋白质表达水平升高，这与前明胶酶A加工能力的诱导同时发生。用MT-MMP的互补脱氧核糖核酸转染的中国仓鼠卵巢（CHO）细胞能够加工野生型前明胶酶A和催化失活的突变体E375A前明胶酶A。两种酶原都被转化为68 kDa的中间（还原凝胶）形式，但只有野生型酶进一步加工成66 kDa的终产物。相比之下，伴刀豆球蛋白A刺激的成纤维细胞通过68 kDa的中间体将两种形式的前明胶酶加工成66 kDa。对伴刀豆球蛋白A刺激的成纤维细胞的质膜制剂加工E375A前明胶酶A的进一步研究表明，添加活性明胶酶A可增强其向成熟形式的加工。得出的结论是，细胞膜介导的前明胶酶A激活可能通过涉及MT-MMP和分子间自溶裂解的级联反应来实现。
