Impact of ALS-linked mutations on the structure, dynamics and function of profilin-1

ALS 相关突变对 profilin-1 结构、动力学和功能的影响

• 批准号: 10533362
• 负责人: Daryl Angela Bosco
• 金额: $ 52.11万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-01-08 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10533362
• 关键词: 3-Dimensional; Acceleration; Actin-Binding Protein; Actins; Affect; Affinity; Amyotrophic Lateral Sclerosis; Binding; Binding Proteins; Binding Sites; Biochemical; Biological; Biological Assay; Biophysics; Categories; Cells; Cellular biology; Chimera organism; Communication; Complex; Computer Simulation; Coupling; Cytoskeletal Proteins; Cytoskeleton; Data; Defect; Diagnosis; Disease; Exhibits; Fluorescence Spectroscopy; Gene Mutation; Genes; In Vitro; Inherited; Link; Mammalian Cell; Measures; Molecular Conformation; Motion; Motor Neurons; Mutation; Neurodegenerative Disorders; Pathogenesis; Pathway interactions; Phenotype; Play; Polymers; Population; Process; Proline; Protein Dynamics; Protein Family; Protein Region; Proteins; Publishing; RNA Processing; Relaxation; Research; Research Personnel; Resolution; Roentgen Rays; Role; Solubility; Specificity; Stress Fibers; Structure; Symptoms; Testing; Thermodynamics; Variant; Work; experimental study; falls; in silico; innovation; link protein; member; molecular dynamics; multidisciplinary; mutant; novel; polymerization; profilin; profilin 1; protein aggregation; proteostasis; screening; small molecule; synergism; trafficking

MASSI/ BOSCO – ABSTRACT Profilin-1 (PFN1) is a 15kDa actin-binding protein that plays a critical role in regulating cytoskeletal dynamics. In order to promote actin polymerization in cells, PFN1-bound actin must bind and synergize with formin proteins. In 2012, we identified mutations in PFN1 that cause the uniformly lethal neurodegenerative disease amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease. Defects in cytoskeletal dynamics and trafficking were already implicated in ALS pathogenesis, however the mechanism(s) by which ALS-linked proteins disrupt these processes is poorly understood. Many in the field predicted that ALS-linked mutations in PFN1 would abrogate the binding of PFN1 to other cytoskeletal proteins, such as actin and/or members of the formin family of proteins. However, rather unexpectedly, our extensive preliminary data show the opposite. ALS-linked PFN1 (ALS-PFN1) exhibits enhanced binding affinity for select formin proteins in cells and in vitro. Further, ALS-PFN1 causes formins to become hyperactivated, leading to accelerated and greater actin polymerization in cells. Our previous biochemical analyses demonstrated that ALS-PFN1 variants are severely destabilized and prone to aggregate. However, the overall three-dimensional x-ray structures of PFN1 mutants are very similar to WT PFN1. Therefore, we hypothesize that altered protein dynamics caused by ALS- mutations account for our observed phenotypes with respect to formin binding, actin polymerization and PFN1 aggregation. To test this hypothesis, Drs. Francesca Massi and Daryl Bosco have formed a multi- disciplinary, collaborative project that combines molecular dynamics (MD), NMR, fluorescence spectroscopy and cell biology to study the interactions of PFN1 with both formins and actin at atomistic resolution. Indeed, our novel preliminary MD simulations indicate that ALS-linked mutations perturb a network of residues within PFN1 that contact both actin and formin. Further, our extensive preliminary NMR data reveal PFN1 residues near the formin-binding interface are affected by actin binding, and that ALS-linked mutations perturb the intrinsic dynamics of PFN1. Collectively, our preliminary data provide a strong premise that altered protein dynamics of ALS-PFN1 contributes to dysregulated actin polymerization and protein aggregation, which are both involved in ALS pathogenesis. Our proposal builds upon our exciting preliminary data to rigorously characterize the dynamics and mechanism(s) of binding between PFN1, actin and formin. These approaches are highly innovative in the context of studying actin dynamics, and are ideal for probing the actin-PFN1-formin ternary complex, for which little is known at atomistic resolution. These studies are expected to have a significant and broad impact on neurodegenerative disease research, as well as on our fundamental understanding of actin dynamics.

MASSI/ BOSCO -摘要 Profilin-1（PFN 1）是一种分子量为15 kDa的肌动蛋白结合蛋白，在调节细胞骨架动力学中起关键作用。 为了促进细胞内肌动蛋白的聚合，PFN 1结合的肌动蛋白必须与细胞内的肌动蛋白结合并协同作用。 proteins. 2012年，我们发现了PFN 1的突变，这些突变导致了一致致命的神经退行性疾病， 肌萎缩侧索硬化症（ALS），也称为卢伽雷病。细胞骨架动力学缺陷， 贩运已经与ALS发病机制有关，但是ALS相关的机制 对蛋白质破坏这些过程的了解很少。该领域的许多人预测， PFN 1将消除PFN 1与其他细胞骨架蛋白的结合，例如肌动蛋白和/或细胞骨架蛋白的成员。 蛋白质家族。然而，出乎意料的是，我们广泛的初步数据显示相反的情况。 ALS连接的PFN 1（ALS-PFN 1）在细胞内和体外表现出对选择性β蛋白的增强的结合亲和力。 此外，ALS-PFN 1导致formins变得过度活化，导致加速和更大的肌动蛋白 细胞内的聚合。我们以前的生化分析表明，ALS-PFN 1变异体是严重的 不稳定且易于聚集。然而，PFN 1突变体的整体三维X射线结构 与WT PFN 1非常相似。因此，我们假设ALS引起的蛋白质动力学改变- 突变解释了我们观察到的表型，如肌动蛋白结合，肌动蛋白聚合， 和PFN 1聚集。为了验证这一假设，Francesca Massi博士和Daryl Bosco博士组成了一个多- 学科，合作项目，结合分子动力学（MD），核磁共振，荧光光谱 和细胞生物学研究PFN 1与formins和肌动蛋白在原子分辨率的相互作用。的确， 我们的新的初步MD模拟表明，ALS连锁突变扰乱了内部的残基网络， PFN 1与肌动蛋白和肌动蛋白都有联系。此外，我们广泛的初步NMR数据显示PFN 1残基 靠近formin结合界面的细胞受到肌动蛋白结合的影响，ALS连锁突变扰乱了细胞的结构， PFN 1的内在动力学。总的来说，我们的初步数据提供了一个强有力的前提， ALS-PFN 1的动力学有助于失调的肌动蛋白聚合和蛋白质聚集， 都参与了ALS的发病机制。我们的建议建立在我们令人兴奋的初步数据， 表征PFN 1、肌动蛋白和肌动蛋白之间结合的动力学和机制。这些方法 在研究肌动蛋白动力学的背景下具有高度创新性，并且是探测肌动蛋白-PFN 1-β的理想选择。 三元复合物，在原子分辨率上知之甚少。这些研究预计将有一个 对神经退行性疾病研究的重大和广泛的影响，以及对我们的基本 理解肌动蛋白动力学。