Exostosin-like 2 regulates FGF2 signaling by controlling the endocytosis of FGF2
Exostosin-like 2 regulates FGF2 signaling by controlling the endocytosis of FGF2
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DOI：
10.1016/j.bbagen.2018.01.002
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发表时间：
2018-04-01
影响因子：
3
通讯作者：
Kitagawa, Hiroshi
中科院分区：
文献类型：
--
作者：
Nadanaka, Satomi;Kitagawa, Hiroshi
背景资料：硫酸乙酰肝素蛋白聚糖广泛表达于细胞表面和细胞外基质中，参与肝素结合生长因子相关的信号转导。因此，硫酸乙酰肝素的量、结构和链长的变化对由肝素结合生长因子如FGF 2控制的细胞生长方面具有深远的影响。外生肌球蛋白糖基转移酶（EXT 1、EXT 2、EXTL 1、EXTL 2和EXTL 3）控制硫酸乙酰肝素的生物合成，并且它们的基因的表达水平调节硫酸乙酰肝素的量、链长度和硫酸化模式。与EXT 1、EXT 2和EXTL 3不同，EXTL 2具有硫酸乙酰肝素链终止的功能。在这里，我们研究了EXTL 2在FGF 2依赖性信号传导中的重要性。方法：我们使用四种细胞系，EXT 1缺陷细胞，EXT 2-，EXTL 2-或EXTL 3-敲低细胞，通过HPLC，qRT-PCR，流式细胞术和蛋白质印迹法研究硫酸乙酰肝素生物合成和FGF 2信号传导。结果：EXT 1、EXT 2或EXTL 3的表达减少会降低硫酸乙酰肝素的生物合成，从而抑制小鼠L成纤维细胞的FGF 2依赖性增殖。相反，虽然敲除EXTL 2增加了硫酸乙酰肝素的量，但由于硫酸乙酰肝素的增加增强了FGF 2向细胞中的掺入，因此FGF 2依赖性增殖被显著抑制。结论：EXTL 2通过调节硫酸乙酰肝素的生物合成以不同于其他外生骨素的方式控制FGF 2信号传导。这项研究为EXTL 2对FGF 2信号转导的调控机制提供了新的见解。
Background: Heparan sulfate proteoglycans are ubiquitously expressed on cell surfaces and in extracellular matrices, and are engaged in heparin-binding growth factor-related signal transduction. Thus, changes in the amounts, structures, and chain lengths of heparan sulfate have profound effects on aspects of cell growth controlled by heparin-binding growth factors such as FGF2. Exostosin glycosyltransferases (EXT1, EXT2, EXTL1, EXTL2, and EXTL3) control heparan sulfate biosynthesis, and the expression levels of their genes regulate the amounts, chain lengths, and sulfation patterns of heparan sulfate. Unlike EXT1, EXT2, and EXTL3, EXTL2 functions chain termination of heparan sulfate. Here, we examined the importance of EXTL2 in FGF2-dependent signaling.Methods: We investigated heparan sulfate biosynthesis and FGF2 signaling using four cell lines, EXT1-deficient cells, EXT2-, EXTL2-, or EXTL3-knockdown cells, by HPLC, qRT-PCR, flow cytometry, and western blotting.Results: Reduced expression of either EXT1, EXT2, or EXTL3 decreased heparan sulfate biosynthesis, and consequently suppressed the FGF2-dependent proliferation of mouse L fibroblasts. In contrast, although knockdown of EXTL2 increased the amounts of heparan sulfate, FGF2-dependent proliferation was significantly inhibited because the increased heparan sulfate enhanced the incorporation of FGF2 into the cells.Conclusions: EXTL2 controls FGF2 signaling through regulation of heparan sulfate biosynthesis in a manner distinct from that of other exostosins.General significance: This study provides new insights into the regulatory mechanisms of FGF2 signaling by EXTL2.