Activation of matrix metalloproteinases on cell surface

(1)恶性黑色素瘤细胞通过延伸称为侵入足的突起来降解细胞下面的明胶凝胶。发现MT 1-MMP定位于侵袭足。以监测细胞表面。MT 1-MMP更易表达，我们将MT 1-MMP与GFP融合，并在黑色素瘤细胞中表达。GFP/MT 1-MMP定位于侵袭足，可见肌动蛋白束。MT 1-MMP在侵袭性CHO-K1细胞中的表达也与肌动蛋白应力纤维呈沿着分布。因此，MT 1-nMMP的定位似乎是通过细胞内的肌动蛋白cytotoxin调节的。(2)MT 1-MMP在体外通过在前肽结构域中引入切割来激活明胶酶A。MT 1-MMP在培养细胞中的表达诱导细胞介导的前明胶酶A活化。为了证实MT 1-MMP在体内是否能作为明胶酶A的激活剂，我们将小鼠基因组的第1 - 4外显子替换为LacZ和Neo基因，建立了基因敲除小鼠。野生型小鼠在胚胎发生期间在各种组织中以高水平表达MT 1-MMP，并且可以观察到组织中明胶酶A原的活化。然而，在基因敲除小鼠中，不能再观察到前明胶酶A的这种激活。因此，我们得出结论，MT 1-MMP是明胶酶A的生理激活剂。

(1) Malignant melanoma cells degrade gelatin gel beneath the cells by extending protrusions called invadpodia. We foud that MT1-MMP localizes on the invadpodia. To monitor the cell surface. MT1-MMP more easily, we made MT1MMP fused with GFP and expressed it in the melanoma cells. Localization of GFP/MT1-MMP was clearly observed at invade podia where actin bundle can be seen. MT1-MMP was also detected along with actin stress fibers when it is expressed in on invasive CHO-K1 cells. Thus, localization of MT1-nMMP seems to be regulated through actin cytoskelton within the cells.(2) MT1-MMP activates pro-gelatinase Aby introducing cleavage in the propeptide domain in vitro. Expression of MT1-MMP in cultured cells induce cell-mediated activation of pro-gelatinase A. To confirm whether MT1-MMP can act as the activator of pro-gelatinase A in vivo, we generatedgene knockout mice by substituting the 1st to 4th exons of mouse genome to LacZ and Neo gene. Wild type mouse express MT1-MMP at high levels in various tissue during embryogenesis and activation of pro-gelatinase A in the tissue can be observed. In the knockout mice, however, such actibation of pro-gelatinase A could not be observed anymore. Thus, we conclued that MT1-MMP is the physiological activator of pro-gelatinase A.