The molecular architecture of perineuronal nets

神经周围神经网络(PNN)是一种引人注目的神经细胞外基质(ECM)结构。 在过去的十年里，人们对它们在神经发育可塑性中所起的关键作用产生了极大的兴趣。这些 复杂的大分子结构与一系列认知功能有关，并在各种情况下发生变化 神经紊乱的症状。尽管人们对PNN的功能越来越感兴趣，但它们的机制 对神经功能的调节知之甚少，因为目前还没有工具或技术来 具体操纵PNN。我们推测，我们无法瞄准和破坏PNN主要是因为 对它们的分子组成或结构缺乏了解。我们在这项提案中的目标是进行一项 已知PNN组分的结构-功能分析以及识别将网络锚定到神经元的蛋白质 表面。利用体外和体内方法的强大组合，我们已经获得了强有力的初步 详细说明新发现的pNN成分受体蛋白酪氨酸磷酸酶zeta(rptpζ) 与PNNS中的TnR(TNR)在分子水平上结合。此外，我们的数据表明， RPTPζ·TNR复合体通过GPI连接蛋白-1(CNTN1)将PNN锚定在神经细胞表面， 这使CNTN1成为迄今发现的第一个PNNS表面结合蛋白。我们的中心假设是 PNNS有一组独特的成分和受体，它们形成PNN并将它们固定在特定的 神经细胞表面，从而定义其独特的结构和功能。这项提案的总体目标是 是确定PNN的特定成分，并通过独特的组合分析PNN的形成 邻近标记分析、蛋白质结合分析和蛋白质X-射线结晶学，以创建工具 专门和精确地瞄准和操纵这些结构。我们的长期目标是使用这些工具 剖析PNN的功能，以便更好地了解疾病的发病机制，并最终针对PNNS 从治疗上讲。在我们强大的初步数据的指导下，这项建议试图发现独特的组成部分 它通过追求三个互不重叠的具体目标来指导国家公安局的大会：1)确定 RPTPζ·TnR复合体在三叉神经节细胞表面的锚定作用；2)追求生物化学和结构 ACAN、HAPLN1和TNR之间相互作用的特征；以及3)识别细胞表面受体和 三七总皂苷的新成分。拟议的工作具有重要意义，因为它将尝试识别唯一的密钥 对PNNS的形成和功能作出贡献的组成部分。圆满完成目标 将提供关键的洞察力和试剂，以具体、准确和最终了解 它们的作用机制。这种方法是创新的，因为它结合了 用生理、生化和结构方法研究这些重要的大分子组装 在中枢神经系统中。最终，拟议的工作可能会对该领域产生变革，并导致关键 对PNN在健康和疾病中作用的机械论见解。

Perineuronal nets (PNNs) are conspicuous neural extracellular matrix (ECM) structures that have garnered significant interest over the last decade for the critical roles they play in neural developmental plasticity. These complex macromolecular structures are implicated in an array of cognitive functions, and are altered in a variety of neurological disorders. Despite the growing interest in PNN functions, the mechanisms by which they modulate neural functions are poorly understood, because there are currently no tools or techniques to manipulate PNNs specifically. We surmise that our inability to target and disrupt PNNs is primarily driven by a lack of understanding of their molecular composition or structure. Our goal in this proposal is to conduct a structure-function analysis of known PNN components as well as to identify proteins that anchor nets to neuronal surfaces. Using a powerful combination of in vitro and in vivo approaches, we have obtained strong preliminary data detailing how the newly identified PNN component receptor protein tyrosine phosphatase zeta (RPTPζ) associates with tenascin-R (TNR) within PNNs at a molecular level. Furthermore, our data indicate that the RPTPζ•TNR complex anchors PNNs to the neuronal cell surface via the GPI-linked protein contactin-1 (CNTN1), which makes CNTN1 the first surface binding protein for PNNs ever identified. Our central hypothesis is that there are a set of unique components and receptors of PNNs that nucleate PNNs and anchor them to specific neuronal cell surfaces, thereby defining their unique structure and functions. The overall objective of this proposal is to identify PNN-specific components and dissect the formation of PNNs through a unique combination of proximity-labeling assays, protein-binding assays, and protein X-ray crystallography in order to create the tools to target and manipulate these structures specifically and precisely. Our long-term goal is then to use these tools to dissect PNN function in order to better understand disease pathogenesis and ultimately to target PNNs therapeutically. Guided by our strong preliminary data, this proposal seeks to discover the unique components that guide the assembly of PNNs by pursuing three non-overlapping specific aims: 1) defining the role of the RPTPζ•TNR complex in anchoring PNNs to neuronal surfaces; 2) pursuing the biochemical and structural characterization of interactions between ACAN, HAPLN1, and TNR; and 3) identifying cell surface receptors and novel components of PNNs. The proposed work is significant because it will attempt to identify the key unique components that contribute to the formation and thereby function of PNNs. Successful completion of the aims will provide key insights and reagents to manipulate PNNs specifically and precisely and ultimately understand their functional mechanisms. This approach is innovative because it brings together a novel combination of physiological, biochemical and structural approaches to investigate these important macromolecular assemblies in the central nervous system. Ultimately, the proposed work could be transformative for the field and lead to key mechanistic insights into of PNN function in health and disease.