The Structure of the Glial Cell Line-derived Neurotrophic Factor-Coreceptor Complex INSIGHTS INTO RET SIGNALING AND HEPARIN BINDING
The Structure of the Glial Cell Line-derived Neurotrophic Factor-Coreceptor Complex INSIGHTS INTO RET SIGNALING AND HEPARIN BINDING
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DOI：
10.1074/jbc.m802543200
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发表时间：
2008-12-12
影响因子：
4.8
通讯作者：
Goldman, Adrian
中科院分区：
文献类型：
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作者：
Parkash, Vimal;Leppanen, Veli-Matti;Goldman, Adrian
胶质细胞源性神经营养因子 (GDNF) 是一种神经元存活因子，以 2:2 的比例与其辅助受体 GDNF 家族受体 α 1 (GFR α 1) 结合，并通过受体酪氨酸激酶 RET 发出信号。我们在肝素模拟物、蔗糖八硫酸盐的存在下以 2.35 埃的分辨率解析了 GDNF(2).GFR α 1(2) 复合物结构。我们的 GDNF(2).GFR α 1(2) 复合物的结构与之前发表的 artemin(2).GFR α 3(2) 复合物的结构在三个方面有所不同。首先，我们通过实验鉴定了两种结构之间配体-GFR α 界面中不同的残基，特别是支持关键保守的 Arg(GFR α)-Glu(配体)-Arg(GFR α) 相互作用的残基。其次，柔性 GDNF 配体“指状”环与刚性的 GFR α 的配合方式不同。第三，我们认为最重要的是，两个四聚体的四级结构不相似，因为两个 GDNF 单体之间的角度不同。这表明 RET-RET 相互作用在不同的配体 (2)-共受体 (2)-RET2 异六聚体复合物中有所不同。与此一致的是，我们发现 GDNF(2).GFR α 1(2) 和 artemin(2).GFR α 3(2) 在丝裂原激活蛋白激酶测定中信号不同。此外，我们通过 RET 磷酸化的诱变和酶联免疫吸附测定表明，RET 可能与结构域 2 和 3 上的 GFR α 1 残基 Arg-190、Lys-194、Arg-197、Gln-198、Lys-202、Arg-257、Arg-259、Glu-323 和 Asp-324 相互作用。根据结构，蔗糖八硫酸酯还与 GFR α 1 结构域 2 中的 Arg(190)-Lys(202) 区域结合。这可以解释 GDNF.GFR α 1 如何介导细胞粘附以及肝素如何通过 RET 抑制 GDNF 信号传导。
Glial cell line-derived neurotrophic factor (GDNF), a neuronal survival factor, binds its co-receptor GDNF family receptor alpha 1 (GFR alpha 1) in a 2: 2 ratio and signals through the receptor tyrosine kinase RET. We have solved the GDNF(2).GFR alpha 1(2) complex structure at 2.35 angstrom resolution in the presence of a heparin mimic, sucrose octasulfate. The structure of our GDNF(2).GFR alpha 1(2) complex and the previously published artemin(2).GFR alpha 3(2) complex are unlike in three ways. First, we have experimentally identified residues that differ in the ligand-GFR alpha interface between the two structures, in particular ones that buttress the key conserved Arg(GFR alpha)-Glu(ligand)-Arg(GFR alpha) interaction. Second, the flexible GDNF ligand "finger" loops fit differently into the GFR alpha s, which are rigid. Third, and we believe most importantly, the quaternary structure of the two tetramers is dissimilar, because the angle between the two GDNF monomers is different. This suggests that the RET-RET interaction differs in different ligand(2)-co-receptor(2)-RET2 heterohexamer complexes. Consistent with this, we showed that GDNF(2).GFR alpha 1(2) and artemin(2).GFR alpha 3(2) signal differently in a mitogen-activated protein kinase assay. Furthermore, we have shown by mutagenesis and enzyme-linked immunosorbent assays of RET phosphorylation that RET probably interacts with GFR alpha 1 residues Arg-190, Lys-194, Arg-197, Gln-198, Lys-202, Arg-257, Arg-259, Glu-323, and Asp-324 upon both domains 2 and 3. Interestingly, in our structure, sucrose octasulfate also binds to the Arg(190)-Lys(202) region in GFR alpha 1 domain 2. This may explain how GDNF.GFR alpha 1 can mediate cell adhesion and how heparin might inhibit GDNF signaling through RET.