Regulation of urokinase plasminogen activator gene transcription in the RAW264 murine macrophage cell line by macrophage colony-stimulating factor (CSF-1) is dependent upon the level of cell-surface receptor
Regulation of urokinase plasminogen activator gene transcription in the RAW264 murine macrophage cell line by macrophage colony-stimulating factor (CSF-1) is dependent upon the level of cell-surface receptor
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DOI：
10.1042/0264-6021:3470313
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发表时间：
2000-04-01
影响因子：
4.1
通讯作者：
Hume, DA
中科院分区：
文献类型：
--
作者：
Fowles, LF;Stacey, KJ;Hume, DA
巨噬细胞集落刺激因子 (CSF-1) 与 c-fms 原癌基因编码的受体 (CSF-1R) 结合，并激活小鼠骨髓源性巨噬细胞中尿激酶纤溶酶原激活剂 (uPA) 基因的转录。本文证明鼠巨噬细胞系 RAW264 通过诱导酪氨酸残基上的细胞质蛋白磷酸化来响应 CSF-1，但不能诱导 uPA 转录。该缺陷与细胞表面选择性未能维持 CSF-1R 相关，而所有 RAW264 细胞在假定的高尔基体/内质网区室中都含有丰富的 CSF-1R。用 CSF-1R 表达质粒转染可实现 CSF-1 依赖性激活针对 uPA 启动子中 Ets/AP1（激活蛋白 1）元件的信号传导通路，该元件先前已被证明是致癌 ras 和蛋白激酶 C 通路的靶点。在 Y807 或 Y559（涉及信号转导的受体酪氨酸磷酸化位点）处表达的 CSF-1R 突变会减少但不会消除 CSF-1 对 uPA 启动子的激活。突变型 CSF1R 质粒的激活是累加性的；没有证据表明存在相互补充。结果表明，CSF-1 维持较高的 uPA 转录需要细胞表面不断出现新的受体。由 CSF-1R 上磷酸化酪氨酸产生的平行、部分冗余的信号通路激活复杂 uPA 启动子上的多个顺式作用元件。
Macrophage colony-stimulating factor (CSF-1) binds to a receptor (CSF-1R) encoded by the c-fms proto-oncogene and activates transcription of the urokinase plasminogen activator (uPA) gene in murine bone-marrow-derived macrophages. This article demonstrates that the murine macrophage cell line RAW264 responds to CSF-1 with inducible phosphorylation of cytoplasmic proteins on tyrosine residues but fails to induce transcription of uPA. The defect was correlated with a selective failure to maintain CSF-1Rs on the cell surface, whereas all RAW264 cells contained abundant CSF-1Rs within the presumptive Golgi/endoplasmic reticulum compartment. Transfection with a CSF-1R expression plasmid permitted CSF-1-dependent activation of the signalling pathway targeting an Ets/AP1 (activator protein 1)element in the uPA promoter that has been shown previously to be a target of oncogenic ras and protein kinase C pathways. Mutation of the expressed CSF-1R at either Y807 or Y559, sites of receptor tyrosine phosphorylation implicated in signal transduction, reduced but did not abolish uPA promoter activation by CSF-1. Activation by mutant CSF1R plasmids was additive; there was no evidence of mutual complementation. The results indicate that maintenance of elevated uPA transcription by CSF-1 requires new receptors emerging continuously on the cell surface. Parallel, partly redundant, signalling pathways arising from phosphorylated tyrosines on the CSF-1R activate multiple cis-acting elements on the complex uPA promoter.