Molecular Mechanisms of Semaphorin/Plexin-mediated Cytoskeletal Reorganization

信号蛋白/丛蛋白介导的细胞骨架重组的分子机制

基本信息

批准号：
10008272
负责人：
JONATHAN R TERMAN
金额：
$ 3.36万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-05 至 2020-09-04
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10008272
关键词：
Actins Addictive Behavior Adult Affect Amino Acids Animal Model Automobile Driving Axon Behavior Binding Biochemical Biological Biological Assay Biological Process Biophysics Brain Cell model Cues Cytoskeletal Modeling Cytoskeleton Dendrites Development Diagnosis Drosophila genus Emotions Enzymes Event F-Actin Family Filament Functional disorder Funding Genetic Genetic Models Goals Human Injury Instruction Learning Ligands Link Mammals Mediating Microfilaments Microtubules Molecular Morphology Motion Mouse Protein Mus Nervous System control Nervous system structure Neurons Neurosciences Research Oxidation-Reduction Oxides Oxidoreductase Polymers Prevention strategy Process Property Protein Family Proteins Recovery Regulation Semaphorins Shapes Signal Pathway Signal Transduction Spinal Cord Stimulus Structure Synaptic Transmission System Testing Therapeutic Time Tissues Traumatic injury Tubulin Vertebral column Walking Work adhesion process axon growth axon guidance axonal guidance cell behavior cell motility extracellular genetic approach genetic regulatory protein in vivo member migration nervous system disorder novel oxidation plexin polymerization prevent receptor response screening spatiotemporal

项目摘要

7. Project Summary/Abstract The goals of this project are to decipher the mechanisms that regulate the actin and microtubule cytoskeletons, the structures underlying neural cell behaviors including morphology, polarity, adhesion, process elongation, motility, navigation, connectivity, and plasticity. To change their size, shape, and connectivity, neurons require actin and tubulin proteins to assemble together into long polymers (F-actin and microtubules, respectively) – and numerous extracellular stimuli have now been identified that alter the assembly and organization of these cytoskeletal structures. Yet, we still know little of how these extracellular cues exert their precise effects on the cytoskeleton. To better understand these mechanisms, my lab has been focusing on one of the largest families of extracellular cues, the Semaphorins (Semas) – which alter neuronal behaviors by eliciting destabilizing effects on both F-actin and microtubules. Our strategy has been to use model organisms and screening approaches to search for proteins that work in the signal transduction cascade utilized by Semas and their Plexin receptors. Among the proteins that we have identified, is a new family of intracellular proteins called the MICALs that are required for Sema/Plexin signal transduction. Now, work in my lab during the previous funding cycle of this R01 has revealed that the MICALs employ a previously unknown Redox signaling system to control the actin cytoskeleton. Namely, we have found that Mical is a novel F-actin disassembly factor – and our results reveal that Sema/Plexin-mediated reorganizations of the actin cytoskeleton can be precisely achieved in space and time through activation of Mical. We have also found that the MICALs belong to a class of oxidoreductase (Redox) enzymes and that Mical employs its Redox enzymatic activity to alter the properties of F-actin. Our work has gone on to identify that Mical uses F-actin as a direct substrate and post- translationally oxidizes conserved amino acids on actin, simultaneously dismantling F-actin and decreasing polymerization. Moreover, we find that this Sema/Plex/Mical-mediated Redox regulation of actin is reversible (by a protein called SelR/MsrB) – and that this specific reversible Redox actin regulatory system directs multiple different biological processes in neuronal and non-neuronal tissues. Therefore, I hypothesize that Sema/Plexin guidance cues utilize a reversible Redox signaling mechanism composed of Mical and SelR to directly and spatiotemporally coordinate cytoskeletal remodeling to drive cellular form and function. I propose to test this hypothesis by following-up on several lines of preliminary observations that illuminate critical molecular mechanisms of Sema/Plexin/Mical-mediated cytoskeletal reorganization including 1) specific types of F-actin/networks of F-actin that are most responsive to Sema/Plex/Mical effects, 2) molecular interactions that allow Sema/Plexins to coordinate the disassembly of the actin and microtubule cytoskeletons, 3) ligand/receptor systems that allow Sema/Plex/Mical cytoskeletal effects to be magnified spatiotemporally, and 4) specific actin regulatory proteins that protect actin filaments from Sema/Plex/Mical effects.

7。项目摘要/摘要该项目的目标是破译调节肌动蛋白和微管细胞骨架的机制，即神经元细胞行为的基础结构，包括形态，极性，粘合剂，过程伸长，运动，导航，连通性和可塑性。为了改变其大小，形状和连通性，需要神经元肌动蛋白和微管蛋白共同组装成长聚合物（分别为F-肌动蛋白和微管） - 现在已经确定了许多细胞外刺激，可以改变这些的组装和组织细胞骨架结构。但是，我们仍然几乎不知道这些细胞外提示如何对细胞骨架。为了更好地了解这些机制，我的实验室一直专注于最大的家庭之一细胞外提示，信号素（SEMA） - 通过引起不稳定的神经元行为改变神经元行为对F-肌动蛋白和微管的影响。我们的策略是使用模型生物和筛选搜索在信号传输中使用的蛋白质的方法丛受体。在我们确定的蛋白质中，是一个新的细胞内蛋白质家族，称为 SEMA/PLEXIN信号转移所需的微分子。现在，在以前的资金中在我的实验室工作该R01的循环表明，Micals员工是一个以前未知的氧化还原信号系统到控制肌动蛋白细胞骨架。也就是说，我们发现微肌动蛋白是一种新型的F-肌动蛋白拆卸因子，并且我们的结果表明，肌动蛋白细胞骨架的Sema/plexin介导的重组可以精确通过微观激活在空间和时间中实现。我们还发现，Micals属于班级氧化还原酶（氧化还原）酶的酶和微雇员的氧化还原酶活性以改变特性 F-肌动蛋白。我们的工作一直在确定Micro使用F-肌动蛋白作为直接底物，并在翻译在肌动蛋白上氧化保守的氨基酸，只需拆卸F-肌动蛋白并减少聚合。此外，我们发现肌动蛋白的这种SEMA/PLEX/MICAL介导的氧化还原调节是可逆的（通过一种称为SELR/MSRB的蛋白质） - 并且这种特定可逆的氧化还原肌动蛋白调节系统指导神经元和非神经元组织中的多个不同的生物学过程。因此，我假设 SEMA/PLEXIN引导提示使用由Micro和Selr组成的可逆氧化还原信号传导机制直接和空间协调细胞骨架重塑以驱动细胞形式和功能。我建议通过跟踪点亮临界的几条初步观察结果来检验这一假设 Sema/plexin/微介导的细胞骨架重组的分子机制，包括1）特定类型 F-肌动蛋白的F-肌动蛋白/网络对SEMA/PLEX/MICAL效应最有反应，2）分子相互作用这允许Sema/plexins协调肌动蛋白和微管细胞骨架的拆卸，3）允许sema/plex/mical细胞骨架效应的配体/受体系统可以放大时空，并且 4）保护肌动蛋白丝免受SEMA/PLEX/MICAL效应的特定肌动蛋白调节蛋白。