MT1-MMP is a cell-surface enzyme whose regulation of pro-MMP-2 and ERK activation position it as a key facilitator of ECM remodelling and cell migration. These processes are modulated by endogenous MMP inhibitors, such as RECK, a GPI-anchored protein which has been shown to inhibit both MT1-MMP and MMP-2 activity. Our previous studies have revealed a link between MT1-MMP levels, and pro-MMP-2 and ERK activation in mammalian cells, as well as MT1-MMP and RECK co-localization in Xenopus embryos. We here investigated how modulation of RECK would impact MT1-MMP and MMP-2 levels, as well as ERK signalling in Xenopus A6 cells. We used a Morpholino approach to knockdown RECK, plasmid transfection to overexpress RECK, and PI-PLC treatment to shed RECK from the cell surface of Xenopus A6 cells. RECK reduction did not alter pERK or MT1-MMP levels, nor MMP-2 activity as measured by zymography; thus RECK-knockdown cells maintained the ability to remodel the ECM. RECK overexpression and PI-PLC treatment both increased ECM remodelling potential through increased MT1-MMP protein and relative MMP-2 activation levels. RECK changes that reduce the ability of the cell to remodel the ECM (overexpression and cell surface shedding) are compensated for by increases in MT1-MMP, and MMP-2 levels as seen by zymography.

中文翻译：

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非洲爪蟾 A6 细胞 RECK 水平的调节：对 MT1-MMP、MMP-2 和 pERK 水平的影响

MT1-MMP 是一种细胞表面酶，其调节 pro-MMP-2 和 ERK 活化使其成为 ECM 重塑和细胞迁移的关键促进剂。这些过程受到内源性 MMP 抑制剂的调节，例如 RECK，一种 GPI 锚定蛋白，已显示可抑制 MT1-MMP 和 MMP-2 活性。我们之前的研究揭示了 MT1-MMP 水平与哺乳动物细胞中的 pro-MMP-2 和 ERK 激活之间的联系，以及非洲爪蟾胚胎中的 MT1-MMP 和 RECK 共定位。我们在这里研究了 RECK 的调制将如何影响 MT1-MMP 和 MMP-2 水平，以及非洲爪蟾 A6 细胞中的 ERK 信号传导。我们使用 Morpholino 方法来敲低 RECK，质粒转染以过度表达 RECK，并使用 PI-PLC 处理从非洲爪蟾 A6 细胞的细胞表面脱落 RECK。RECK 减少不会改变 pERK 或 MT1-MMP 水平，酶谱法测量的 MMP-2 活性也不；因此 RECK 敲低细胞保持了重塑 ECM 的能力。RECK 过表达和 PI-PLC 处理均通过增加 MT1-MMP 蛋白和相对 MMP-2 活化水平来增加 ECM 重塑潜力。RECK 降低细胞重塑 ECM（过表达和细胞表面脱落）能力的变化通过 MT1-MMP 和 MMP-2 水平的增加得到补偿，如酶谱法所见。