The role of the C3 domain of myosin binding protein-C in the pathogenesis of hypertrophic cardiomyopathy

 描述（由申请方提供）：心肌肌球蛋白结合蛋白C（cMyBP-C）是一种心脏肌节的调节蛋白，有助于收缩储备。cMyBP-C突变是肥厚型心肌病（HCM）的主要原因，HCM是一种影响全球约1/500人的疾病。cMyBP-C的截断突变主要通过单倍不足引起HCM;然而，致病错义突变的发病机制尚未完全了解。C-末端结构域对于并入肌节是必需的，而N-末端结构域通过磷酸化依赖性抑制相互作用调节收缩。中央结构域在cMyBP-C生理功能中的作用尚不清楚。cMyBP-C的C3结构域中的R495 Q和R502 W突变是HCM最常见的原因之一，然而它们如何影响功能并促成病理表型仍然未知。研究表明，该区域的突变可能会破坏推定的蛋白质结合结构域。考虑到它们在C3结构域中的位置，我们假设R495 Q和R502 W突变通过修饰结构域C3与尚未确定的配体之间的相互作用来调节收缩性。在这个博士前的建议，我们将表达突变体R495 Q和R502 W cMyBP-C在小鼠三维心脏组织结构，然后通过评估收缩性，钙处理，钙敏感性和β-肾上腺素能刺激的反应。为了确定这些突变与HCM的联系机制，我们将使用当代蛋白质组学方法来定义C3结构域的功能，并评估这些突变是否改变了推定的蛋白质-蛋白质相互作用。确定C3结构域的功能将有助于深入了解cMyBP-C的整体功能，HCM的发病机制，并可能确定新的治疗策略，以预防或改变疾病进展。这个博士前研究计划是一个综合培训计划的一部分，该计划充分利用威斯康星大学麦迪逊分校强大的研究环境，以提高候选人向成功的生物医学研究科学家的可能过渡。

 DESCRIPTION (provided by applicant): Cardiac myosin binding protein C (cMyBP-C) is a regulatory protein of the cardiac sarcomere that contributes to contractile reserve. Mutations in cMyBP-C are a leading cause of hypertrophic cardiomyopathy (HCM), a disease that affects about 1 in 500 people worldwide. Truncation mutations in cMyBP-C cause HCM primarily through haploinsufficiency; however, the pathogenesis of disease-causing missense mutations is not well understood. The C-terminal domains are essential for incorporation into the sarcomere, while the N-terminal domains modulate contraction through phosphorylation-dependent inhibitory interactions. The role of the central domains in the physiologic function of cMyBP-C is unclear. The R495Q and R502W mutations in the C3 domain of cMyBP-C are among the most prevalent causes of HCM, however exactly how they affect function and contribute to the pathologic phenotype remains unknown. Studies suggest that mutations in this region may disrupt a putative protein binding domain. Given their location in the C3 domain we hypothesize that the R495Q and R502W mutations modulate contractility by modifying an interaction between domain C3 and an as-yet undefined ligand. In this pre-doctoral proposal, we will express mutant R495Q and R502W cMyBP-C in murine three-dimensional cardiac tissue constructs followed by assessment of contractility, calcium handling, calcium sensitivity and responsiveness to beta-adrenergic stimulation. To identify the mechanism linking these mutations to HCM, we will use contemporary proteomics approaches to define the function of the C3 domain and assess whether these mutations alter putative protein-protein interactions. Determining the function of the C3 domain will provide insight into the overall function of cMyBP-C, the pathogenesis of HCM, and may identify novel treatment strategies to prevent or modify disease progression. This pre-doctoral research proposal is part of a comprehensive training program which takes full advantage of the strong research environment at the University of Wisconsin-Madison to enhance the candidate's likely transition to a successful biomedical research scientist.