THE N-TERMINAL MYOSIN-ELC REGULATION OF CARDIAC MUSCLE CONTRACTION

N 端肌球蛋白-ELC 对心肌收缩的调节

• 批准号: 8361291
• 负责人: Danuta Szczesna-Cordary
• 金额: $ 0.99万
• 依托单位: ILLINOIS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8361291
• 关键词: Ablation; Actins; Amino Acids; Biophysics; Cardiac; Cardiac Muscle Contraction; Data; Development; Funding; Genetic; Grant; Head; Length; Microfilaments; Molecular Conformation; Mus; Muscle Contraction; Myocardium; Myosin ATPase; Myosin Heavy Chains; N-terminal; National Center for Research Resources; Phenotype; Positioning Attribute; Principal Investigator; Publishing; Radial; Regulation; Relative (related person); Research; Research Infrastructure; Resources; Role; Source; Surface; Takeda brand of pioglitazone hydrochloride; Testing; Thick Filament; Thin Filament; Time; Transgenic Mice; United States National Institutes of Health; X ray diffraction analysis; X-Ray Diffraction; cost

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. It has been known for some time that during muscle contraction the long N terminus of cardiac ELC makes direct contacts with actin. To study how this might regulate contractility, we generated transgenic mice expressing a 43 amino acid residue truncation of the ELC N terminus (Tg-D43) (Kazmierczak et al. JMB 387, 706-725, 2009). We hypothesize that the N-terminal ELC extension regulates force development in cardiac muscle via its direct contacts with actin and/or through influencing the conformation of the myosin heavy chain(MHC) and its interaction with actin,. Another possibility is that the N-terminus of ELC acts as a tether pre-positioning the myosin heads for attachment to actin and facilitating Acto-myosin interaction. The lack of the N-terminal ELC extension would therefore result in a decreased maximal force and lower myofilament cooperativity, the phenotypes that we observe in our published preliminary data with Tg-D43 mice. This project will help determine whether the genetic ablation of the N-terminus of ELC may result in radial and/or azimuthal displacement of Tg-D43 crossbridges, such that they may re-locate further from the surface of the thin filaments and closer to the myosin thick filaments. To test this, we will use low-angle X-ray diffraction to compare lattice spacings and equatorial intensity ratios (I1,1/I1,0) to assess the proximity of myosin cross-bridge mass relative to actin in Tg-D43 mouse myocardium compared to Tg-WT mice containing a full length ELC N-terminus. This will elucidate the regulatory role of the N-terminal ELC extension in muscle contraction.

该副本是利用资源的众多研究子项目之一 由NIH/NCRR资助的中心赠款提供。对该子弹的主要支持 而且，副投影的主要研究员可能是其他来源提供的 包括其他NIH来源。 列出的总费用可能 代表subproject使用的中心基础架构的估计量， NCRR赠款不直接向子弹或副本人员提供的直接资金。 一段时间以来，在肌肉收缩期间，心脏ELC的长N末端与肌动蛋白直接接触。 为了研究这可能如何调节收缩力，我们产生了表达ELC N末端的43个氨基酸残基截断（TG-D43）的转基因小鼠（Kazmierczak等人JMB 387，706-725，2009）。我们假设N末端ELC扩展通过与肌动蛋白的直接接触和/或影响肌球蛋白重链（MHC）的构象来调节心肌的力发育，以及与肌动蛋白的相互作用。另一种可能性是，ELC的N末端充当了肌球蛋白头的束缚，以依赖肌动蛋白并促进肌动蛋白的相互作用。因此，缺乏N末端ELC扩展将导致最大力量降低并降低肌丝协作性，这是我们使用TG-D43小鼠在发布的初步数据中观察到的表型。该项目将有助于确定ELC的N末端的遗传消融是否可能导致TG-D43 Crossbridges的径向和/或方位角位移，从而使它们可以从薄细丝的表面更远地重新放置，并更接近肌球蛋白浓稠的细丝。为了进行测试，我们将使用低角度的X射线衍射来比较与包含全长ELC N-终端的TG-WT小鼠相比，肌球蛋白跨桥质量相对于TG-D43小鼠心肌中肌动蛋白相对于肌动蛋白的肌球蛋白跨桥质量相对于肌动蛋白的近端相对于肌动蛋白质量相对于肌动蛋白的近端。 这将阐明N末端ELC扩展在肌肉收缩中的调节作用。