STRUCTURAL STUDY OF EPH RECEPTORS

该子项目是利用资源的许多研究子项目之一 由NIH/NCRR资助的中心拨款提供。次级项目的主要支助 子项目的主要研究者可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 在正常和致癌发育过程中，Eph受体酪氨酸激酶和它们的肝配蛋白配体调节细胞导航。Ephs的信号传导是在一个多步骤的过程中启动的，导致高阶信号簇的组装，这些信号簇在相互作用的细胞中引发双向信号传导。然而，这个组件的结构和机械细节仍然不确定。我们请求国际象棋A1 beamtine来确定完整的EphA 4胞外域的结构和与ephrin-A5作为Eph簇的基本单元的复合物。我们还获得了与小分子抑制剂结合的EphA 4晶体，我们将收集关于该晶体的数据。 不过，我们现在已经改进了晶体的尺寸和质量，并希望能够收集更高分辨率的数据。 将使用与EphA 4具有显著序列同一性（50%）的其它Eph受体片段的已知结构的分子置换来确定结构。我们以前也确定了未结合肝配蛋白-A5的结构。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Eph receptor tyrosine kinases and their ephrin ligands regulate cell navigation during normal and oncogenic development. Signaling of Ephs is initiated in a multistep process leading to the assembly of higher-order signaling clusters that set off bidirectional signaling in interacting cells. However, the structural and mechanistic details of this assembly remained undefined. We request Chess A1 beamtine to determine the structures of the complete EphA4 ectodomain and complexes with ephrin-A5 as the base unit of an Eph cluster. We have also obtained crystals of EphA4 bound to a small-molecule inhibitor which we will collect data on. Previous crystallographic data collection on our EphA4 and EphA4/ephrin-A5 crystals reveal diffraction to approximately 4.0 A. We have now, though, improved the size and quality of the crystals, and expect that we will be able to collect higher-resolution data. The structures will be determined using molecular replacement with known structures of fragments of other Eph receptors which share significant sequence identity (50%) to EphA4. We have also previously determined the structure of unbound ephrin-A5.