Understanding Signaling by Non-Canonical Receptor Tyrosine Kinases

项目摘要 这项在Mira申请中提出的研究试图了解未探索的 受体酪氨酸激酶(RTK)超家族的跨膜信号传递，其成员发挥着 在人类疾病中发挥重要作用-从神经发育障碍，到骨骼疾病，癌症，糖尿病， 还有几个先天畸形。在RTK信号转导的传统观点中，生长因子配体诱导 受体二聚体成为酪氨酸自动磷酸化，并招募下游信号分子。因为我们 更多地了解20个不同的RTK家族(其中包括58个RTK)，然而，它变得更加清晰 这一观点只适用于这些受体的一部分。这里提出的研究集中在两个方面 需要非常不同的机制观点的特征--结合Wnt蛋白的RTK(而不是 结果是二聚体)和在其胞内区具有“死亡”的激酶或假蛋白激酶的RTK。新的 为了理解这些重要的受体是如何发出信号的，必须理解这些范例。我们的目标结束了 接下来的5-10年是：1.对RTK在WNT信号中所起的作用形成一个连贯的图景( 涉及20个RTK家族中的4个)，2.为了了解带有伪激酶结构域的RTK是如何 Bind ATP(在20个RTK家族中的5个中发现)可以发出信号，以及3.为了确定为什么假蛋白激酶过度- 在受WNT调控的RTK中具有代表性。以细胞和体内受体/配体研究为导向 我们将从生物化学和高分辨结构的角度研究配体诱导的络合物。 方法，以详细了解Wnt蛋白结合如何导致受体激活和 信号复合体中的辅助受体。在进行这些研究时，我们会调查WNT所扮演的角色 酰化-其与FrizzledWnt家族和RTK家族Wnt结合的要求似乎不同 感受器。我们还希望在Wnt蛋白中定义不同信号模式的特异性决定因素。 在这些追求的同时，我们将使用结构指导的方法，结合化学生物学和 对突变受体进行功能分析，探讨假蛋白在RTK中的信号转导机制 超级大家庭。这些研究将对被认为是10%的人类亲属具有重要的意义 并将系统地检验这一假说，即受调控的伪激酶转换 信令需要一致性。我们的方法也将为治疗带来新的机会 靶向假性激酶，如PTK7、Ror2和Ror1，它们与几种疾病有关。 总之，我们的研究将为通过一类受体传递信号提供重要的基础性新见解 不适合RTK或Wnt受体的正常范例。了解它们对于解卷积至关重要。 Wnt信号特异性的复杂性及其多重作用的梳理。此外，我们的发现应该是 为潜在的治疗抑制开辟新的途径--这些Wnt结合的RTK在疾病中的作用 变得越来越清晰。

Project Summary The research proposed in this MIRA application seeks to understand unexplored mechanisms of transmembrane signaling across the receptor tyrosine kinase (RTK) superfamily, members of which play an important role in human disease – from neurodevelopmental disorders, to bone diseases, cancers, diabetes, and several congenital malformations. In the traditional view of RTK signaling, growth factor ligands induce receptor dimers that become tyrosine autophosphorylated and recruit downstream signaling molecules. As we understand more about the 20 different RTK families (which include 58 RTKs), however, it becomes clearer that this view only applies to a subset of these receptors. The research proposed here focuses on two characteristics that demand a very different mechanistic view – RTKs that bind Wnt proteins (and do not dimerize as a result) and RTKs that have `dead' kinase or pseudokinases in their intracellular regions. New paradigms must be understood in order to appreciate how these important receptors signal. Our goals over the next 5-10 years are: 1. To develop a coherent picture of the role played by RTKs in Wnt signaling (which involves 4 of the 20 RTK families), 2. To understand how RTKs with pseudokinase domains that do not even bind ATP (found in 5 of the 20 RTK families) can signal, and 3. To determine why pseudokinases are over- represented among the Wnt-regulated RTKs. Guided by cellular and in vivo studies of receptor/ligand relationships we will study ligand-induced complexes biochemically, and with high-resolution structural approaches, in order to understand in detail how Wnt protein binding leads to activation of the receptors and co-receptors in the signaling complex. In pursuing these studies, we will investigate the role played by Wnt acylation – requirements for which appear to be different for binding to Frizzled-family and RTK-family Wnt receptors. We also hope to define specificity determinants in the Wnt proteins for distinct modes of signaling. In parallel with these pursuits, we will use a structurally-guided approach, combined with chemical biology and functional analysis of mutated receptors, to explore the mechanism of signaling by pseudokinases in the RTK superfamily. These studies will have important implications for the 10% of the human kinome thought to be pseudokinases, and will systematically test the hypothesis that regulated switching of pseudokinase conformation is required for signaling. Our approaches will also bring new opportunities for therapeutic targeting of pseudokinases such as PTK7, Ror2, and Ror1, which have been implicated in several diseases. Together, our studies will provide important fundamental new insight into signaling by a class of receptors that do not fit into normal paradigms for RTKs or Wnt receptors. Understanding them is crucial for deconvoluting the complexity of Wnt signaling specificity and teasing out its multiple roles. In addition, our findings should open new avenues for potential therapeutic inhibition – as the roles of these Wnt-binding RTKs in disease become increasingly clear.