Translational Control of Cardiac Excitability

项目摘要/摘要 心脏的正常跳动需要有条理地表达特定于 心室复极、起搏、传导等功能。最近的进展建立了一个新的 协调渠道表达的方式。这一提议的中心假设是 相互作用的信使核糖核酸物种的“微翻译组”编码功能相关的蛋白质，例如 产生心脏动作电位。这些离子通道以共翻译的方式组装成大分子 控制高阶心脏兴奋性的复合体。该提案的目的是解决 单分子原位荧光法研究共翻译复合体介导的心脏复极 胚胎(IPSC)和成人(IPSC)的杂交结合蛋白免疫荧光(smFISH/IF) 心肌细胞。关于这些物质的组成、化学计量和细胞定位的假设 复合体将接受测试。这种复合体是否调节其他心脏功能，如起搏，将 要下定决心。介导mRNA关联的机制，如候选RNA结合蛋白(RBPs) 亲和捕获质谱学鉴定，以及直接的信使核糖核酸相互作用，将被解决。这些 研究有望阐明控制心脏兴奋性的新机制，并确定新的 疾病和治疗发展的目标。

PROJECT SUMMARY/ABSTRACT The regular beating of the heart requires the orchestrated expression of ion channel ensembles specific for ventricular repolarization, pacemaking, conduction and other functions. Recent progress establishes a new way in which channel expression is coordinated. The central hypothesis of this proposal is that a “microtranslatome” of interacting mRNA species encodes functionally related proteins, such as those producing the ventricular action potential. These ion channels assemble cotranslationally into macromolecular complexes that govern higher-order cardiac excitability. The aims of the proposal are to resolve components of cotranslational complexes mediating cardiac repolarization using single-molecule fluorescence in situ hybridization combined with protein immunofluorescence (smFISH/IF) in both embryonic (iPSC) and adult cardiomyocytes. Hypotheses regarding the composition, stoichiometry and cellular localization of these complexes will be tested. Whether such complexes regulate other cardiac functions, such as pacemaking, will be determined. Mechanisms mediating mRNA association, such as candidate RNA binding proteins (RBPs) identified with affinity-capture mass spectrometry, and direct mRNA interactions, will be resolved. These studies are expected to illuminate new mechanisms by which cardiac excitability is controlled and identify novel targets for disease and therapeutic development.