Oligomerization reduces heparin affinity but enhances receptor binding of fibroblast growth factor 2
Oligomerization reduces heparin affinity but enhances receptor binding of fibroblast growth factor 2
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DOI：
10.1042/0264-6021:3450107
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发表时间：
2000-01-01
影响因子：
4.1
通讯作者：
Yayon, A
中科院分区：
文献类型：
--
作者：
Safran, M;Eisenstein, M;Yayon, A
细胞对成纤维细胞生长因子(FGFs)的生物学反应依赖于具有特定结构基序的硫酸乙酰肝素糖胺聚糖。肝素诱导的成纤维细胞生长因子二聚化被认为是介导受体二聚化和激活的途径。在这里，我们证明了肝素衍生的促进受体结合和激活的寡糖特异性地诱导碱性成纤维细胞生长因子(FGF2)的二聚化，这些由肝素诱导的FGF2二聚体获得与受体结合的高亲和力，并且具有生物学活性。使用生物素化的FGF2与生物素逐渐饱和的固定化链霉亲和素结合，可以对肝素依赖和肝素非依赖的FGF2单体和低聚物进行定量分析。链霉亲和素诱导的FGF2二聚体只有在肝素存在的情况下才能结合和激活成纤维细胞生长因子受体。过量的链霉亲和素迫使生物素-FGF2进入单体，减少受体结合，并阻止依赖于成纤维细胞生长因子的细胞增殖。所有这些都表明肝素相关的FGF2寡聚体主要与受体结合并激活。出乎意料的是，肝素诱导的二聚体和高阶低聚物失去了对肝素的大部分亲和力。可溶性成纤维细胞生长因子受体(FGFRs)与FGF2的单体或二聚体直接结合，并固定在肝素上，证实了FGFRs与FGF2二聚体的优先结合。计算机化的分子对接预测了一个顺式导向的FGF2二聚体，它由肝素稳定，符合所有的实验数据。
The biological response of cells to fibroblast growth factors (FGFs) depends on heparan sulphate glycosaminoglycans sharing particular structural motifs. Heparin induced FGF dimerization has been suggested to mediate receptor dimerization and activation. Here we demonstrate that heparin-derived oligosaccharides that promote receptor binding and activation specifically induce the dimerization of basic FGF (FGF2), These heparin-induced dimers of FGF2 acquire high affinity for receptor binding and are biologically active. Using biotinylated FGF2 bound to immobilized streptavidin gradually saturated with biotin, enabled a quantitative analysis of heparin-dependent and heparin-independent FGF2 monomers and oligomers. Streptavidin induced FGF2 dimers bind and activate FGF receptors only in the presence of heparin. An excess of streptavidin, forcing biotin-FGF2 into monomers, reduces receptor binding and blocks FGF-dependent cell proliferation. All these suggest predominant receptor binding and activation by heparin associated FGF2 oligomers. Unexpectedly, heparin induced dimers and higher order oligomers lose most of their affinity towards heparin. Direct binding of soluble FGF receptors (FGFRs) to either monomers or dimers of FGF2, immobilized on heparin, confirm the preferred association of FGFRs with dimers of FGF2. Computerized molecular docking predicts a cis-oriented FGF2 dimer, stabilized by heparin, which complies with all the experimental data.