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.

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 众所周知，在肌肉收缩过程中，心脏ELC的长N端与肌动蛋白直接接触。为了研究这可能如何调节收缩能力，我们培育了表达ELC N末端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)。我们推测，N端ELC延伸通过与肌动蛋白的直接接触和/或通过影响肌球蛋白重链(MHC)的构象及其与肌动蛋白的相互作用来调节心肌的力量发育。另一种可能性是，ELC的N-末端起到系绳的作用，预先定位肌球蛋白头部以连接肌动蛋白，并促进肌动蛋白相互作用。因此，缺乏N-末端ELC延伸将导致最大力降低和肌丝协同性降低，这些表型我们在我们发表的TG-D43小鼠的初步数据中观察到。该项目将有助于确定ELC N-末端的遗传消融是否会导致TG-D43交叉桥的径向和/或方位移位，从而使它们可能重新定位到离细丝表面更远的地方，更接近肌球蛋白粗丝的位置。为了测试这一点，我们将使用小角X射线衍射来比较晶格间距和赤道强度比(I1，1/I1，0)，以评估与包含全长ELC N-末端的TG-WT小鼠相比，TG-D43小鼠心肌中肌球蛋白跨桥质量相对于肌动蛋白的接近程度。这将阐明N端ELC延伸在肌肉收缩中的调节作用。