ALTERED CALCIUM REGULATION IN CARDIOMYOPATHIES

心肌病中钙调节的改变

• 批准号: 6530726
• 负责人: P. Bryant Chase
• 金额: $ 32.74万
• 依托单位: FLORIDA STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2005-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6530726
• 关键词: actins; binding sites; calcium flux; gene mutation; hypertrophic myocardiopathy; laboratory rabbit; laboratory rat; microfilaments; molecular pathology; phosphorylation; protein binding; protein structure function; troponin

DESCRIPTION (the applicant's description verbatim): Mutations in cardiac thin filament protein troponin I (cTnI) have been identified as causal in some forms of familial hypertrophic cardiomyopathy (FHC). The overall goal of this proposal is to characterize functional consequences of these six disease-related mutations in the C-terminus of cTnI. Specific predictions about their effects on steady-state force-pCa relationship derive from the localization of mutations in binding of TnI's C-terminus to: (i) the N-terminus of cTnC (R145G and R145Q mutations in the inhibitory peptide and R162W); or (ii) actin-Tm (R145G and R145Q mutations in the inhibitory peptide which is part of actin-Tm binding site I and K183delta which is part of actin-Tm binding site II). In addition, C-terminal truncation studies of TnI predict that R162W, K183delta, G203S and K206Q could all compromise the ability of cTn to relax the myocardium during diastole. Recombinant cTnI constructs will be altered with mutations found in FHC. Mutant and wild type (WT) constructs will be incorporated into permeabilized muscle preparations-for measurements of sarcomere mechanics-and into regulated actin filaments-for measurements on single actin filaments using in vitro motility assays. Mutant proteins will be tested, first by complete substitution of mutant for WT, secondly in varying proportions of WT and mutant as occurs in the diseased myocardium, and thirdly with additional mutations that mimic phosphorylation of Ser22 & Ser23 or Thr143 (introduction of acidic residues). For each mutation, we will determine the effects on Ca2+ sensitivity of steady-state isometric force, filament sliding, and the rate of tension redevelopment (kTR; a parameter that is important for evaluating cardiac function). The results will aid understanding normal Ca2+ regulation of the heart, pathological mechanism(s) of hypertrophy, and the assays will he useful for identifying treatments.

描述（申请人的描述逐字描述）：心脏薄中的突变 细丝蛋白肌钙蛋白I（CTNI）已被确定为某些形式的因果关系 家族性肥厚性心肌病（FHC）。总体目标 建议是表征这六个的功能后果 CTNI的C末端中与疾病相关的突变。关于特定预测 它们对稳态力-PCA关系的影响来自 TNI C末端结合中突变的定位与：（i）N末端 CTNC（抑制性肽和R162W中的R145G和R145Q突变）；或者 （ii）肌动蛋白-TM（抑制性肽中的R145G和R145Q突变 At actin-TM结合位点I和K183DELTA的一部分，它是artm-TM结合的一部分 站点II）。此外，TNI的C末端截断研究预测R162W， K183delta，G203S和K206Q都可能损害CTN放松的能力 舒张期间的心肌。重组CTNI构建体将随着 在FHC中发现的突变。突变和野生型（WT）结构将是 纳入透化的肌肉制剂，以进行测量 肌节力学，并进入受调节的肌动蛋白丝进行测量 单肌动蛋白丝使用体外运动测定法。突变蛋白将是 测试，首先是通过将突变体完全取代为wt进行的，其次是不同的 wt和突变体的比例与患病的心肌发生，第三 随着模拟Ser22和Ser23或Thr143的其他突变 （引入酸性残基）。对于每个突变，我们将确定 对稳态等距，细丝滑动的CA2+灵敏度的影响， 以及张力再开发的速率（KTR；对于重要的参数 评估心脏功能）。结果将有助于理解正常的Ca2+ 心脏的调节，肥大的病理机制和 分析对于识别治疗方法有用。