Molecular Recognition Principles, Engineering and Function of Neural Wiring Receptors

 描述(由申请人提供)：神经连接，连接神经系统细胞的突触的集合，是神经系统的主要属性，也是神经功能的决定因素。在人类中，数十亿个神经元产生数万亿个突触，而这个系统的正常功能依赖于正确的连接。不正确的神经元连接可能会导致不正确的感知和各种神经发育疾病。虽然人们普遍认为这种连接是由细胞表面受体决定的，这些受体唯一地标记神经元并机械地指导它们的连接，但我们知道的这种受体的数量相对较少。鉴于神经系统的复杂性，我们需要发现更多的神经受体并了解它们是如何发挥作用的，以便能够了解大脑发育和以神经连接为中心的疾病的生理。为了解决这个问题，我们正在努力揭示细胞表面受体的身份和生理功能，这些受体唯一地标记神经元并指导它们的连接。以前，使用生化方法(蛋白质相互作用筛选)，我们已经在果蝇中鉴定出两个蛋白质家族，dprs和dips，它们是神经连通性的决定因素，并且是可能指导突触配对的一个独特的“相互作用密码”。 大脑中的神经元。DPR和DIP家族的成员之间并不是以简单的一对一方式相互联系；每个DPR和DIP与许多DIP和DPR相互作用，这种现象我们称为“交叉反应”，并调节一组独特的相互作用。此外，我们还发现了一种名为Common DIP(CDIP)的分泌蛋白，它结合了30个dprs和dIP中的21个，可能对DPR/DIP介导的神经连接具有调节功能。在这里，我们打算揭示建立这一密码的分子原理，包括57个相互作用，并在体外、培养和体内研究DPR/DIP引导的突触形成的生物学。我们的多方面方法包括(1)DPR-DIP相互作用的生物物理和结构特征，随后是DPR-DIP工程，以创建新的分子亲和力，用于测试果蝇大脑中新的神经连接性；(2)DPR-DIP介导的粘连的细胞研究以及共同DIP对这些细胞粘连的影响；以及(3)建立一个基于细胞的系统，通过转化生长因子-β/骨形态发生蛋白信号通路研究DPR和DIP的信号转导。

 DESCRIPTION (provided by applicant): Neural connectivity, the collection of synapses wiring nervous system cells, is a major property of a nervous system, and a determinant of neural function. In humans, billions of neurons make trillions of synapses, and the proper function of this system depends on proper wiring. Incorrect wiring of neurons can lead to improper perception and various neurodevelopmental diseases. While it is generally accepted that the connectivity is determined by cell surface receptors that uniquely label neurons and mechanistically guide their wiring, we know a relatively few number of these receptors. Given the complexity of nervous systems, we need to discover more neural receptors and learn how they function, so as to be able to understand brain development and the physiology of diseases where neural wiring is central. To address this, we are working to reveal the identity and physiological function of cell surface receptors that uniquely label neurons and guide their wiring. Previously, using a biochemical approach (protein interaction screening), we have identified two protein families, Dprs and DIPs in Drosophila, that are determinants of neural connectivity, and are a unique case of an "interaction code" that likely guides synaptic pairing of neurons in the brain. Members of Dpr and DIP families bind each other not in a simple one-to-one fashion; each Dpr and DIP interacts with many DIPs and Dprs, a phenomenon we call "cross-reactivity", and mediates a unique set of interactions. In addition, we have discovered a secreted protein we have named common DIP (cDIP), which binds 21 out of 30 Dprs and DIPs, and likely has a regulatory function on Dpr/DIP-mediated neural connections. Here, we propose to reveal the molecular principles that establish this code, which includes 57 interactions, and study the biology of Dpr/DIP- guided synapse formation in vitro, in culture and in vivo. Our multi-faceted approach includes (1) a biophysical and structural characterization of the Dpr-DIP interactions, followed by engineering of Dprs and DIPs to create novel molecular affinities to be tested for novel neural connectivity in the Drosophila brain; (2) a cellular study of Dpr-DIP mediated adhesions and the effect of the common DIP on these cell adhesions; and (3) the creation of a cell-based system for studying the signaling of Dprs and DIPs via the TGF-β/BMP signaling pathway.