Mechanisms of Local Protein Synthesis in Axon Arborization

局部蛋白质合成使亚细胞区室具有不同的生物学功能。 神经元轴突离细胞体很远。虽然有成千上万的mRNA存在于 轴突和功能失调的轴突蛋白质合成与多种疾病有关，我们 了解轴突中局部蛋白质合成的分子机制， 基本上是有限的。轴突分支在神经系统功能中起着关键作用，因为它定义了 一个合适的突触连接区域长期目标是阐明 控制局部蛋白质合成及其在轴突分支中的作用。当前的目标 应用是为了获得对细胞质的作用和调节机制的见解， 多聚腺苷酸化元件结合蛋白（CPEB）在轴突蛋白合成和轴突分支中的作用 通过使用果蝇作为模型系统。CPEB通过以下途径控制靶蛋白翻译： 胞质去腺苷酸化和多腺苷酸化。我们的初步研究支持一个模型， CPEB，Orb 2抑制唐氏综合征细胞粘附分子的蛋白合成 Dscam通过胞质去腺苷化作用在细胞体中表达，并介导Dscam mRNA 运输到轴突，其中Wallenda/双亮氨酸拉链激酶（Wnd/DLK）去抑制 Orb 2的翻译抑制。新开发的创新方法将用于研究 以下两个目标。在目的1中，Orb 2在轴突Dscam蛋白合成中的作用将被阐明。 测定在目标2中，将研究Wnd对Orb 2的调节机制。生理 所鉴定的机制的作用将在体内使用轴突分支来确定。Orb 2/CPEB是 对长期记忆的形成很重要。Dscam与多种脑部疾病有关。 Wnd/DLK在多种神经元事件中起关键作用。因此，捐款将是 重要的是，它将提供Orb 2/CPEB在轴突蛋白合成中的新作用， Wnd/DLK对轴突蛋白质合成的调控，以及Dscam表达和 定位于轴突。预期的结果是新的分子调控机制， 轴突蛋白质合成及其在轴突分支形成中的作用。了解分子 轴突蛋白质合成和树枝化的机制将最终有助于开发有效的 治疗脑部疾病

Local protein synthesis enables distinct biological functions of subcellular compartments. Neuronal axons are far apart from the cell body. Although thousands of mRNAs are present in axons and dysfunctional axonal protein synthesis is linked to multiple disorders, our understanding of the molecular mechanisms underlying the local protein synthesis in axons is largely limited. Axon arborization plays a critical role in nervous system function because it defines a territory for proper synaptic connection. The long-term goal is to elucidate the mechanisms that govern localized protein synthesis and their role in axon arborization. The objective of current application is to gain mechanistic insights on the role and the regulation of the cytoplasmic polyadenylation element binding protein (CPEB) in axonal protein synthesis and axon arborization by using Drosophila as a model system. CPEB controls target protein translation through cytoplasmic de- and poly-adenylation. Our preliminary studies support a model that a Drosophila CPEB, Orb2 suppresses the protein synthesis of Down syndrome cell adhesion molecule (Dscam) in the cell body through cytoplasmic deadenylation and mediates Dscam mRNA transport to axon where Wallenda/Dual leucine zipper kinase (Wnd/DLK) de-represses the translational suppression by Orb2. The newly developed innovative approach will be used to study the following two aims. In Aim 1, the role of Orb2 in axonal Dscam protein synthesis will be determined. In Aim 2, the regulatory mechanism of Orb2 by Wnd will be studied. The physiological role of identified mechanisms will be determined using axon arborization in vivo. Orb2/CPEB is important for long-term memory formation. Dscam is implicated in multiple brain disorders. Wnd/DLK plays a key role in multiple neuronal events. Therefore, the contribution will be significant because it will provide a novel role of Orb2/CPEB in axonal protein synthesis, a novel axonal protein synthesis regulation by Wnd/DLK, and a mechanism of Dscam expression and localization in axons. The expected outcome is the novel molecular regulatory mechanisms in axonal protein synthesis and their role in axon arborization. Understanding the molecular mechanisms of axonal protein synthesis and arborization will ultimately help developing effective treatment to brain disorders.