SP-1 regulation of MMP-9 expression requires Ser586 in the PEST domain.
SP-1 regulation of MMP-9 expression requires Ser586 in the PEST domain.
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DOI：
10.1042/bj20120053
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发表时间：
2012-07-15
期刊：
影响因子：
--
通讯作者：
Carter AB
中科院分区：
文献类型：
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作者：
Murthy S;Ryan AJ;Carter AB
Rac1是一种小的GTP酶，以ERK和SP-1依赖的方式调节巨噬细胞基质金属蛋白酶-9(MMP9)。SP-1含有一个可能调节蛋白质稳定性的PEST结构域。我们推测，PEST结构域中的T578、S586和/或S587是SP-1稳定和继而激活丝氨酸/苏氨酸激酶ERK后表达基质金属蛋白酶-9所必需的。我们检测了Rac1和ERK对SP-1WT和SP-1突变体T578A、S586A和S587A驱动的基质金属蛋白酶-9表达的影响。WT和突变型SP-1的表达增加了肺泡巨噬细胞中基质金属蛋白酶-9的启动子活性。然而，结构性活性的rac1抑制表达SP-1WT、SP-1T578A和SP-1S587A的细胞中的MMP-9启动子活性，但不抑制SP-1S586A的活性。此外，在表达SP-1WT但不表达SP-1S586A的细胞中，组成性ERK激活可显著增加表达SP-1WT而不是SP-1S586A的基质金属蛋白酶-9的转录。由于rac1的激活和ERK的失活增加了SP-1WT的降解，而不是SP-1S586A的降解，我们的结果表明，S586处的SP-1的稳定性调节了基质金属蛋白酶-9的转录。在体内，石棉肺患者的肺泡巨噬细胞表达较少的基质金属蛋白酶-9，这与SP-1表达和ERK活性降低有关。这些观察结果表明，SP-1 PEST结构域中的S586对肺泡巨噬细胞中基质金属蛋白酶-9基因的表达具有重要作用，并强调了这些蛋白在肺纤维化中的重要性。
Rac1, a small GTPase, regulates macrophage matrix metalloproteinase-9 (MMP-9) in an ERK- and SP-1-dependent manner. SP-1 contains a PEST domain that may modulate protein stability. We hypothesize that T578, S586, and/or S587 in the PEST domain are required for SP-1 stability and MMP-9 expression secondary to activation of ERK, a serine/threonine kinase. We determined the effects of Rac1 and ERK on MMP-9 expression driven by SP-1WT and SP-1 mutants, T578A, S586A and S587A. Expression of WT and mutant SP-1 increased MMP-9 promoter activity in alveolar macrophages. However, constitutively active Rac1 suppressed MMP-9 promoter activity in cells expressing SP-1WT, SP-1T578A, and SP-1S587A, but not SP-1S586A. Furthermore, constitutive ERK activation, which was inhibited by Rac1, significantly increased MMP-9 transcription in cells expressing SP-1WT but not SP-1S586A. Because Rac1 activation and ERK inactivation increased degradation of SP-1WT and not SP-1S586A, our results suggest that SP-1 stability mediated at S586 regulates MMP-9 transcription.. In vivo, alveolar macrophages obtained from asbestosis patients had less MMP-9 that was associated with decreased SP-1 expression and ERK activation. These observations demonstrate that S586 in the PEST domain of SP-1 is important for MMP-9 gene expression in alveolar macrophages and highlight the importance of these proteins in pulmonary fibrosis.