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.

马西/博斯科-摘要 Profilin-1(PFN1)是一种15 kDa的肌动蛋白结合蛋白，在调节细胞骨架动力学中起着关键作用。 为了促进细胞内肌动蛋白的聚合，PFN1结合的肌动蛋白必须与Form in结合并协同作用 蛋白质。2012年，我们确定了导致这种统一致命的神经退行性疾病的PFN1突变 肌萎缩侧索硬化症(ALS)，也被称为卢·格里克病。细胞骨架动力学缺陷和 贩卖已经与肌萎缩侧索硬化症的发病有关，然而肌萎缩侧索硬化症与肌萎缩侧索硬化症联系的机制(S) 人们对蛋白质破坏这些过程知之甚少。该领域的许多人预测，ALS相关的突变在 PFN1将取消PFN1与其他细胞骨架蛋白的结合，如肌动蛋白和/或 形成蛋白家族。然而，相当出人意料的是，我们广泛的初步数据显示出相反的情况。 ALS连接的PFN1(ALS-PFN1)在细胞和体外对选定的Forin蛋白具有增强的结合亲和力。 此外，ALS-PFN1导致福尔马林过度激活，导致加速和更大的肌动蛋白 细胞内的聚合作用。我们之前的生化分析表明，ALS-PFN1变种严重 不稳定且容易聚集。然而，PFN1突变体的整体三维X射线结构 与WT PFN1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关于Forin结合、肌动蛋白聚合的表型 和PFN1聚集性。为了验证这一假设，弗朗西斯卡·马西博士和达里尔·博斯科博士形成了一个多个 结合分子动力学(MD)、核磁共振、荧光光谱学的学科协作项目 和细胞生物学，在原子分辨率下研究PFN1与福尔马林和肌动蛋白的相互作用。的确， 我们新的初步MD模拟表明，与ALS相关的突变扰乱了 既能接触肌动蛋白又能接触福尔明的PFN1。此外，我们广泛的初步核磁共振数据显示，PFN1残基 靠近福尔马林结合界面的基因受到肌动蛋白结合的影响，而与肌萎缩侧索硬化相关的突变扰乱了 PFN1的内在动力学。总而言之，我们的初步数据提供了一个强有力的前提，即改变蛋白质 ALS-PFN1的动力学有助于肌动蛋白聚合和蛋白质聚集的失调，这是 两者都参与了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的基础上，以严格 描述PFN1、肌动蛋白和福明之间结合的动力学和机制(S)。这些方法 在研究肌动蛋白动力学方面具有很高的创新性，是探索肌动蛋白-PFN1形成的理想选择 三元络合物，对其原子分辨知之甚少。这些研究预计将有一个 对神经退行性疾病研究的重大而广泛的影响，以及对我们的基础 对肌动蛋白动力学的理解。