Polarity Signals and MyosinII Coordinate Neuron Migration and Germinal Zone Exit

极性信号和肌球蛋白 II 协调神经元迁移和生发区退出

基本信息

批准号：
8236545
负责人：
David Joseph Solecki
金额：
$ 38.28万
依托单位：
ST. JUDE CHILDREN'S RESEARCH HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8236545
关键词：
Actins Actomyosin Address Adhesions Binding Biochemical Bioinformatics Biological Assay Brain Calmodulin Cell Adhesion Centrosome Clinical Cognition Disorders Complex Cytoplasmic Granules Cytoskeletal Modeling Cytoskeleton Data Development Disease Dynein ATPase Ectopic Expression Elements Epilepsy Equilibrium Erinaceidae Foundations Gene Silencing Genetic Models Goals Image Immigration Kinetics Knowledge Laboratories Lead Length Life Link Malignant Childhood Neoplasm Mental Retardation Methods Mitogens Modeling Molecular Motors Morphogenesis Motor Movement Myosin ATPase Myosin Heavy Chains Myosin Light Chain Kinase Myosin Light Chains Myosin Type I Myosin Type II Neurites Neurons Nonmuscle Myosin Type IIB Organelles Phenotype Phosphorylation Positioning Attribute Preparation Process Protein Binding Radial Regulation Signal Transduction Signaling Molecule Signaling Protein Site Slice Testing Time Uncertainty adhesion process base cell motility cellular imaging developmental disease imaging probe insight interest loss of function migration mutant neuronal circuitry novel prevent progenitor programs scaffold smoothened signaling pathway time use

项目摘要

DESCRIPTION (provided by applicant): Neuronal migration is essential for the morphogenesis of the developing brain, and defective migration or germinal zone (GZ) exit contributes to profound developmental and cognitive disorders, such as mental retardation, epilepsy and pediatric cancer [1-4]. Despite recent advances implicating the cytoskeleton as a critical regulator of neuronal motility [5, 6], a key remaining challenge is to understand how disparate elements (substrate adhesions, cytoskeletal components and signaling molecules) are coordinated to cooperatively execute complex neuronal motility programs, such as nucleokinesis or GZ exit. Studies in my laboratory using the cerebellar granule neuron (CGN) model illustrate that signaling through the partitioning defective (PAR) polarity complex regulates multiple aspects of neuronal motility, including radial migration initiation, neuronal adhesion to migration substrates, the cadence of nucleokinesis (i.e., centrosomal and somal motility) and a potential functional interaction between the PAR complex and Myosin II, a molecular motor that is essential for nucleokinesis [7-9]; however, the upstream regulators and downstream effectors of the PAR during these processes are currently unclear. The long-term goal of this proposal is to characterize upstream regulators and downstream effector(s) of the PAR complex critical for migration to elucidate how cytoskeletal organization, adhesion dynamics and migration initiation are globally coordinated during brain development. We will use gain- and loss-of-function approaches in combination with advanced live cell imaging in ex vivo cerebellar slice preparations to test three hypotheses related to our long term goal: I. Myosin II, an actin-based motor, powers polarized organelle motility and leading-process adhesion dynamics during nucleokinesis. II. The PAR complex regulates myosin II motors to orchestrate cytoskeletal and adhesion dynamics required for nucleokinesis. III. A competitive balance between Shh signaling and Par6 regulates CGN GZ exit and radial migration initiation through JAM-C adhesion. We propose three Aims to address each of these hypotheses: Aim 1: Determine whether leading process Myosin II motors are necessary for centrosomal and somal motility and leading process adhesion dynamics during radial migration. Aim 2: Demonstrate that Par6 regulates Myosin II activity and JAM-C adhesions by scaffolding actomyosin components via an IQ motif. Aim3: Determine whether excess Shh activity in Patched heterozygous CGNs regulates Par6 dependant GZ exit and JAM-C adhesion. At the end of this study, we will create a new conceptual framework for an integrated model of neuronal motility and provide novel insight into the pathological mechanisms of neuronal positioning disorders and pediatric cancer. PUBLIC HEALTH RELEVANCE: Proper regulation of neuronal positioning directs the formation of the neuronal laminae that are the foundation of neuronal circuitry. Errors in migration lead to developmental abnormalities that are the basis of diseases like mental retardation, epilepsy and pediatric cancer. The goal of this proposal is to understand the function of key signaling proteins and molecular motors, which are promising targets to understand the forces that power the migration of neurons in the developing brain, information that will be essential to eventually prevent or treat neuronal positioning disorders.

描述（由申请人提供）：神经元迁移对于发育中的大脑的形态发生至关重要，迁移缺陷或生发区 (GZ) 退出会导致严重的发育和认知障碍，例如智力低下、癫痫和小儿癌症 [1-4 ]。尽管最近的进展表明细胞骨架是神经元运动的关键调节剂 [5, 6]，但仍然存在的一个关键挑战是了解不同的元素（基质粘附、细胞骨架成分和信号分子）如何协调以协作执行复杂的神经元运动程序，例如作为核分裂或 GZ 退出。我的实验室使用小脑颗粒神经元 (CGN) 模型进行的研究表明，通过分区缺陷 (PAR) 极性复合体的信号传导调节神经元运动的多个方面，包括径向迁移起始、神经元对迁移基质的粘附、核运动的节奏（即，中心体和体细胞运动）以及 PAR 复合物和肌球蛋白 II 之间潜在的功能相互作用，肌球蛋白 II 是核运动所必需的分子马达[7-9]；然而，目前尚不清楚这些过程中 PAR 的上游调节器和下游效应器。该提案的长期目标是表征对迁移至关重要的 PAR 复合物的上游调节器和下游效应器，以阐明细胞骨架组织、粘附动力学和迁移启动在大脑发育过程中如何进行全局协调。我们将使用功能获得和丧失功能的方法与离体小脑切片制备中的先进活细胞成像相结合，来测试与我们的长期目标相关的三个假设： I. 肌球蛋白 II，一种基于肌动蛋白的马达，为极化细胞器提供动力核分裂过程中的运动性和主导过程粘附动力学。二. PAR 复合物调节肌球蛋白 II 马达，以协调核分裂所需的细胞骨架和粘附动力学。三． Shh 信号传导和 Par6 之间的竞争平衡通过 JAM-C 粘附调节 CGN GZ 退出和径向迁移启动。我们提出三个目标来解决这些假设：目标 1：确定主导过程肌球蛋白 II 马达是否对于中心体和体细胞运动以及径向迁移过程中主导过程粘附动力学是必需的。目标 2：证明 Par6 通过 IQ 基序搭建肌动球蛋白成分来调节肌球蛋白 II 活性和 JAM-C 粘附。目标 3：确定 Patched 杂合 CGN 中过量的 Shh 活性是否调节 Par6 依赖的 GZ 退出和 JAM-C 粘附。在本研究结束时，我们将为神经元运动的综合模型创建一个新的概念框架，并为神经元定位障碍和儿科癌症的病理机制提供新的见解。公共卫生相关性：神经元定位的正确调节可指导神经元层的形成，而神经元层是神经元回路的基础。迁移错误会导致发育异常，这是智力低下、癫痫和小儿癌症等疾病的基础。该提案的目标是了解关键信号蛋白和分子马达的功能，它们是了解驱动发育中大脑中神经元迁移的力量的有希望的目标，这些信息对于最终预防或治疗神经元定位障碍至关重要。