Eph and Lyn hyper-phosphorylation and CRMP interactions in AD"

Eph受体在心血管和神经元发育中为细胞迁移做出指导决定， 疾病和再生Eph受体也与大脑的高级功能，记忆和 学习一种与阿尔茨海默氏症、帕金森氏症和其他神经系统疾病有关的蛋白质 和损伤是与几种激酶相互作用的塌陷蛋白反应介导蛋白（CRMP） 并且随着激酶的活化增加而变得过度磷酸化。超- 磷酸化的CRMP然后破坏肌动蛋白和微管细胞骨架结构的形成， 被认为阻碍Aβ和tau蛋白清除。细胞质林恩激酶是Fyn激酶的近亲， 已知与EphA 4直接相互作用，在这里，我们第一次表明，EphA家族成员 EphB 2直接与CRMP相互作用。类似于另一种引导和细胞迁移系统， Fyn-丛状蛋白-CRMP复合物，Lyn-EphA 4-CRMP缔合可能与Cdk 5形成复合物， GSK 3 β激酶，每种都与阿尔茨海默氏症有关。Eph-CRMP和Eph-Lyn的特点 相互作用的界面需要表征，因为它们将是潜在的生物标志物和靶点， 治疗干预该提案有两个主要目标。目的1）寻求建立体外 在EphA 4和-B2的细胞内结构域上的各种激酶的磷酸化模式， CRMP的存在和不存在，并进一步验证细胞中复合物的形成。目标2） 相应的磷酸模拟物/磷酸缺陷突变对活性水平的影响 这些Eph受体的细胞内区域和激酶将研究与纯化的蛋白质， 体外最终，利用本项目的知识，抗体或复合物破坏肽可以 推动早期检测诊断和/或治疗的未来发展。

Eph receptors make guidance decisions for cell migration in cardiovascular and neuronal development, disease, and regeneration. Eph receptors are also involved with higher brain functions, memory and learning. A protein that has been associated with Alzheimer’s, Parkinson’s and other neuronal diseases and injuries is the Collapsin Response Mediator Protein (CRMP) which interacts with several kinases and becomes hyper-phosphorylated alongside increased activation of the kinases. The hyper- phosphorylated CRMP then disrupts the formation of actin and microtubule cytoskeletal structures and it thought to impede Aβ and tau clearance. Cytosolic Lyn kinase, a close homologue of Fyn kinase, is known to interact directly with EphA4 and here, for the first time, we show that an EphA family member and EphB2 directly interacts with CRMP. Analogous to another guidance and cell migration system, the Fyn-Plexin-CRMP complex, the Lyn-EphA4-CRMP association is likely to form a complex with Cdk5 and GSK3β kinases, each also involved in Alzheimer’s. The features of the Eph-CRMP and Eph-Lyn interacting interfaces need to be characterized, as they will be potential biomarkers and targets for therapeutic intervention. The proposal has two main aims. Aim 1) seeks to establish the in vitro phosphorylation patters of various kinases on the intracellular domains of EphA4 and –B2 in the presence and absence of CRMP and to further validate the formation of the complex in cells. Aim 2) The effect that the corresponding phosphomimetic/phospho-defective mutations have on the level of activity on these Eph receptor intracellular regions and of the kinases will be studied with purified proteins in vitro. Eventually, using the knowledge from this project, Antibodies or complex-disrupting-peptides may drive the future development of early detection diagnostics and/or therapeutics.