Structural Dynamics of Cardiac Myosin-Binding Protein C Regulation

心肌肌球蛋白结合蛋白 C 调节的结构动力学

• 批准号: 10545008
• 负责人: Brett A Colson
• 金额: $ 38.38万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-01-01 至 2024-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10545008
• 关键词: Acceleration; Accounting; Actins; Address; Affect; Artificial skin; Binding; Biological Assay; Cardiac; Cardiac Muscle Contraction; Cardiac Myosins; Cardiomyopathies; Computer Simulation; Data; Deceleration; Development; Disease; Equilibrium; Evaluation; FDA approved; Fiber; Filament; Fluorescence; Fluorescence Resonance Energy Transfer; Fluorescence Spectroscopy; Frequencies; Genes; Health; Heart; Heart Diseases; Human; Hypertrophic Cardiomyopathy; In Situ; In Vitro; Individual; Inherited; Kinetics; Knowledge; Label; Lead; Measurement; Measures; Mechanics; Medical; Microfilaments; Molecular; Molecular Conformation; Monitor; Muscle; Muscle function; Mutation; Myocardial; Myocardium; Myosin ATPase; N-terminal; Pathogenesis; Pathogenicity; Pathologic; Performance; Phenotype; Phosphorylation; Physiological; Positioning Attribute; Property; Protein Dynamics; Proteins; Publishing; Recombinants; Regulation; Reporter; Reporting; Research; Resolution; Role; Sarcomeres; Site; Skin; Stress; Structure; Sudden Death; Technology; Testing; Therapeutic; Thick Filament; Thin Filament; Thinness; Time; Visualization; Work; biophysical tools; cardiac muscle disease; data exchange; design; effective therapy; heart cell; improved; in silico; in vivo; innovation; molecular dynamics; mutant; myosin-binding protein C; novel; protein structure; simulation; tool

PROJECT SUMMARY Hypertrophic cardiomyopathy (HCM) is a relatively common disease affecting more than 1 in 500 individuals and the leading cause of sudden death in young individuals and athletes. HCM is an unmet medical need with no FDA-approved treatments. ~40% of all HCM cases are associated with mutations in the gene encoding cardiac myosin-binding protein C (MyBP-C). MyBP-C is a thick filament-associated protein that is critical for normal myocardial performance; it is centrally positioned in the sarcomere to regulate interactions between myosin cross-bridges and actin thin filaments that are responsible for force development. We have previously demonstrated that increased phosphorylation of MyBP-C enhances actin-myosin interactions leading to accelerated contraction kinetics in myocardium, whereas reduced phosphorylation led to reduced actin-myosin proximity and decelerated contraction. However, it is not understood how MyBP-C phosphorylation alters the structural dynamics of its interactions with actin and/or myosin to modulate force development in normal myocardium or how mutations alter functions that ultimately contribute to HCM pathogenesis. We have developed innovative biophysical tools that, for the first time, enable evaluation of: (1) the structural dynamics of MyBP-C, (2) how it interacts with actin and/or myosin in muscle, and (3) how these interactions are affected by phosphorylation and known pathologic mutations. We will test the central hypothesis that phosphorylation and HCM mutations of N-terminal MyBP-C alter functionally significant structural properties of MyBP-C and interactions with actin and myosin. Aim 1 will evaluate the effects of phosphorylation, HCM mutations, and binding to actin or myosin on MyBP-C structural dynamics. Spectroscopic approaches will be employed to detect conformational changes (structure) within MyBP-C due to phosphorylation, HCM mutation, and actin/myosin binding (function). Molecular dynamics (MD) simulations will be applied as a complementary approach. Aim 2 will determine how MyBP-C phosphorylation and HCM mutants affect proximities and dynamics of key myocardial proteins. We will utilize site-directed probe technologies in skinned (demembranated) cardiac fibers to determine how phosphorylation/mutants affect protein structure/interactions in situ to regulate contractility. The proposed studies capture structural dynamics in real time and resolve interactions in real myocardial space using novel high-resolution approaches. These aims are a stepwise progression developing a new paradigm for studying normal and mutant MyBP-C during the contractile cycle. This paradigm involves monitoring distances between points on proteins and the order (or disorder) of those distances under physiological conditions, in interacting proteins and functioning myocardium. Not all HCM mutants impact the same functions of MyBP-C. Time-resolved fluorescence data components, thin/thick filament dynamics, mechanics, and simulations will be used to separate mutants into identifiable bins, setting the stage for identifying mechanistic-based therapies to specifically treat different classes of mutations.

项目总结