Structures of the EphA2 Receptor at the Membrane: Role of Lipid Interactions.
Structures of the EphA2 Receptor at the Membrane: Role of Lipid Interactions.
复制标题
DOI：
10.1016/j.str.2015.11.008
复制
发表时间：
2016-02-02
期刊：
影响因子：
--
通讯作者：
Sansom MS
中科院分区：
文献类型：
--
作者：
Chavent M;Seiradake E;Jones EY;Sansom MS
Ephs是介导细胞间信号传导的跨膜受体。n端外结构域结合配体并使受体聚集，从而激活细胞内激酶。相对而言，关于外结构域的膜-近端纤维连接蛋白结构域2 （FN2）的功能知之甚少。多尺度分子动力学模拟表明，FN2通过一个由K441、R443、R465、Q462、S464、S491、W467、F490和P459-461组成的位点与脂质双分子层相互作用。FN2优先结合阴离子脂质，这种偏好在突变体K441E + R443E中减少。我们通过测量野生型和突变型FN2结构域与脂质囊泡的结合来证实这些结果。在完整的EphA2外畴和跨膜区域的模拟中，我们发现FN2将原本灵活的外畴固定在双分子层的表面。总之，我们的数据表明，FN2具有与阴离子脂质相互作用和限制EphA2外畴结构采用膜近端结构的双重功能。EphA2受体外结构域主要通过其FN2结构域与脂质双分子层相互作用阴离子脂质通过FN2突变K441E和R443E中的带正电荷残基募集，取消了FN2与阴离子脂质的特异性结合。FN2-双分子层相互作用使EphA2外结构域相对于膜定向，Chavent等人结合多尺度分子动力学模拟和生化分析来描述EphA2受体FN2结构域与阴离子脂质的相互作用膜。这提供了深入了解受体在细胞表面的动态行为。
Ephs are transmembrane receptors that mediate cell-cell signaling. The N-terminal ectodomain binds ligands and enables receptor clustering, which activates the intracellular kinase. Relatively little is known about the function of the membrane-proximal fibronectin domain 2 (FN2) of the ectodomain. Multiscale molecular dynamics simulations reveal that FN2 interacts with lipid bilayers via a site comprising K441, R443, R465, Q462, S464, S491, W467, F490, and P459–461. FN2 preferentially binds anionic lipids, a preference that is reduced in the mutant K441E + R443E. We confirm these results by measuring the binding of wild-type and mutant FN2 domains to lipid vesicles. In simulations of the complete EphA2 ectodomain plus the transmembrane region, we show that FN2 anchors the otherwise flexible ectodomain at the surface of the bilayer. Altogether, our data suggest that FN2 serves a dual function of interacting with anionic lipids and constraining the structure of the EphA2 ectodomain to adopt membrane-proximal configurations. EphA2 receptor ectodomain mainly interacts with lipid bilayers via its FN2 domain Anionic lipids are recruited by positively charged residues in FN2 Mutations K441E and R443E abolish the specific binding of FN2 to anionic lipids The FN2-bilayer interaction orients the EphA2 ectodomain relative to a membrane Chavent et al. combine multiscale molecular dynamics simulations with a biochemical assay to describe the interactions of the EphA2 receptor FN2 domain with the anionic lipids of a model membrane. This provides insights into the dynamic behavior of the receptor at the cell surface.