Activation of matrix metalloproteinases on cell surface

(1)恶性黑色素瘤细胞通过延伸被称为内足突的突起来降解细胞下的明胶凝胶。我们发现MT1-MMP定位于内足部。监测细胞表面。MT1-MMP更容易，我们将MT1MMP与GFP融合并在黑色素瘤细胞中表达。侵袭足部可见GFP/MT1-MMP的定位，可见肌动蛋白束。当MT1-MMP在侵袭性CHO-K1细胞中表达时，也可以与肌动蛋白应激纤维一起检测到。因此，MT1-nMMP的定位似乎是通过细胞内的肌动蛋白细胞骨架调节的。(2) MT1-MMP在体外激活前明胶酶Aby，在前肽区域引入切割。在培养细胞中表达MT1-MMP可诱导细胞介导的前明胶酶A的激活。为了证实MT1-MMP是否可以在体内作为前明胶酶A的激活剂，我们通过将小鼠基因组的第1至第4外显子替换为LacZ和Neo基因来产生基因敲除小鼠。野生型小鼠在胚胎发生过程中在各组织中高水平表达MT1-MMP，并观察到组织中前明胶酶A的激活。然而，在基因敲除小鼠中，这种前明胶酶A的激活不再被观察到。因此，我们得出结论，MT1-MMP是前明胶酶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.