Function of Giant Sarcomere Matrix Proteins in Muscle

肌肉中巨肌节基质蛋白的功能

• 批准号: 7626490
• 负责人: Henk L. GRANZIER
• 金额: $ 37.73万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-08-01 至 2012-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7626490
• 关键词: Actins; Acute; Adrenergic Agents; Adult; Alternative Splicing; Animal Model; Be++ element; Beryllium; Binding; Calcium; Calcium-Binding Proteins; Cardiac; Cardiovascular system; Cells; Crystallins; Cyclic AMP-Dependent Protein Kinases; Data; Dependence; Development; Diastole; Elements; Functional disorder; Goals; Heart; Heart Diseases; Immunoelectron Microscopy; In Vitro; Indium; Ischemia; Knock-out; Knockout Mice; Length; Measures; Mechanics; Mediating; Microfilaments; Modeling; Molecular; Muscle; Muscle Cells; Muscle function; Mutation; Myocardial; Myocardium; Nature; Physiological; Physiology; Play; Property; Protein Isoforms; Proteins; Rattus; Reperfusion Injury; Reporting; Research; Research Personnel; Role; Sarcomeres; Shapes; Signal Transduction; Skeletal Muscle; Stretching; Striated Muscles; Structure; Sturnus vulgaris; Systole; Techniques; Testing; Thick Filament; Viscosity; Work; X ray diffraction analysis; X-Ray Diffraction; adrenergic; base; connectin; heart function; mouse model; mutant; novel; programs; response; single molecule

DESCRIPTION (provided by applicant): Titin is multi-functional giant filamentous protein with many important effects on structure and function of muscle. The long-term goal of this project is to determine the mechanisms whereby titin influences passive and active muscle physiology, particularly with respect to the cardiovascular system. Our work in cardiac muscle has shown that titin's l-band spring region contains distinct extensible elements that shape both its short-term properties and, through alternative splicing, its long-term adaptation. These distinct regions are the tandem Ig and PEVK elements found in both cardiac and skeletal muscle and the N2B element found only in cardiac muscle. Recent evidence suggests that the PEVK and N2B elements uniquely modulate passive cardiac muscle stiffness, and that this modulation is important for shaping heart function and adaptation. We will focus on elucidating these unique mechanisms in myocardial mechanics, including the role of S100A1 in regulating the PEVK-based mechanism. We will use novel knock-out (KO) models in which the PEVK or N2B element has been excised and a model that is deficient in S100A1 (SKO). We will also critically test the hypothesis that titin regulates active myocardial force development by studying the PEVK KO and N2B KO mouse models (high passive stiffness) as well as a contrasting rat model that expresses a giant titin isoform (low passive stiffness). We will measure the length dependence of calcium sensitivity and the effect of titin on myofilament structure (using low angle X-ray diffraction). We will accomplish the proposed research using a multi-faceted approach, with experimental techniques at levels ranging across the single molecule, single cell, whole muscle, and the intact heart. Our research will contribute to understanding passive stiffness modulation, including its role in ischemia-reperfusion injury, and the interplay between titin-based passive stiffness and active force development. Passive myocardial stiffness is an important determinant of diastolic filling and utilization of the Frank-Starling mechanism, and our research will contribute to understanding the roles of titin in both diastolic and systolic dysfunction.

描述（申请人提供）：Titin是一种多功能巨型丝状蛋白，对肌肉的结构和功能具有许多重要作用。该项目的长期目标是确定肌联蛋白影响被动和主动肌肉生理学的机制，特别是在心血管系统方面。我们在心肌中的研究表明，肌联蛋白的l-带弹簧区域包含不同的可延伸元件，这些元件塑造了肌联蛋白的短期特性，并通过选择性剪接形成了肌联蛋白的长期适应性。这些不同的区域是在心肌和骨骼肌中发现的串联IG和PEVK元件以及仅在心肌中发现的N2 B元件。最近的证据表明，PEVK和N2 B元件独特地调节被动心肌僵硬度，并且这种调节对于塑造心脏功能和适应是重要的。我们将重点阐明这些独特的心肌力学机制，包括S100 A1在调节PEVK为基础的机制中的作用。我们将使用新的敲除（KO）模型，其中PEVK或N2 B元件已被切除，以及S100 A1（SKO）缺陷的模型。我们还将通过研究PEVK KO和N2 B KO小鼠模型（高被动刚度）以及表达巨大肌联蛋白同种型（低被动刚度）的对比大鼠模型来严格检验肌联蛋白调节主动心肌力发展的假设。我们将测量钙敏感性的长度依赖性和肌联蛋白对肌丝结构的影响（使用低角X射线衍射）。我们将使用多方面的方法完成拟议的研究，实验技术的水平范围包括单分子，单细胞，整个肌肉和完整的心脏。我们的研究将有助于理解被动刚度调制，包括其在缺血再灌注损伤中的作用，以及基于肌联蛋白的被动刚度和主动力发展之间的相互作用。被动心肌僵硬度是舒张期充盈和Frank-Starling机制利用的重要决定因素，我们的研究将有助于了解肌联蛋白在舒张期和收缩期功能障碍中的作用。