Myosin Gene Diversity and Function

肌球蛋白基因多样性和功能

基本信息

批准号：
10400923
负责人：
Leslie Anne Leinwand
金额：
$ 52.1万
依托单位：
UNIVERSITY OF COLORADO
依托单位国家：
美国
项目类别：
财政年份：
1981
资助国家：
美国
起止时间：
1981-09-01 至 2024-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10400923
关键词：
Affect Alternative Splicing Amino Acids Back Biochemical Biology Biophysics Birds Brain Cardiac Myocytes Cardiac Myosins Cardiomyopathies Cells Data Defect Disease Ear Electron Microscopy Gene Expression Gene Family Genes Goals Grant Half-Life Health Hip region structure Homeostasis Hour Human Isotopes Labyrinth Link Mammals Mass Spectrum Analysis Measures Molecular Motors Motor Movement Mus Muscle Muscle Cells Muscle Fibers Muscle function Mutation Myocardium Myopathy Myosin ATPase Myosin Heavy Chains Myosin Rod Pathogenicity Persons Physiology Process Measure Property Proteins Pythons RNA Rod Role Sarcomeres Skeletal Muscle Striated Muscles Technology Testing Thick Filament Tissues Untranslated RNA cardiac muscle disease cell type disease-causing mutation genome editing heart imaging hereditary hearing loss in vivo induced pluripotent stem cell member molecular imaging mouse model mutant novel response single molecule skeletal trafficking

项目摘要

PROJECT SUMMARY More than 500 human sarcomeric myosin heavy chain mutations in multiple members of the 10 gene family cause 11 distinct heart and skeletal muscle diseases. Myosin consists of a globular motor domain and an α- helical rod domain, with disease-causing mutations throughout. Despite having studied the myosin gene family for many years, we have recently discovered unexpected biology such as a “sarcomeric” myosin in mammalian brains and inner ears and the rapid movement of single myosin molecules in and out of sarcomeres. Our goal is to understand the diversification of the myosin gene family, how different myosins drive muscle function, and how mutations in the same residue of the same myosin gene give rise to skeletal or cardiac muscle disease. To accomplish these goals, we propose integrated structural, biophysical, cellular and in vivo approaches with WT and mutant myosins. The unorthodox MYH7b protein is found in striated muscles of pythons and birds, but only a small number of mammalian muscles expresses the protein. We will compare the functions of python and human MYH7b proteins, testing the hypothesis that human MYH7b protein has evolved from the typical sarcomeric motor seen in python to its use in specialized mammalian muscles, where it is sarcomeric, and in a subset of cells in the brain and the inner ear. Its role in the inner ear is intriguing since compound heterozygous mutations in MYH7b are linked to hereditary hearing loss and we will study these mutant myosin’s. Most mammalian muscles express abundant MYH7b RNA that cannot produce protein due to an alternative splicing mechanism. Our hypothesis, backed up by strong preliminary data, is that mammalian non-coding MYH7b RNA regulates expression of the highly expressed Type I slow skeletal/β cardiac myosin. The myosin composition of muscles is dynamic and known to drive physiology, but very little is known about how myosin moves into and out of sarcomeres in health and disease. The much longer half-life of myosin protein (~10 days) compared to its sarcomeric replacement rates (5-14 hours) suggests that each molecule undergoes multiple rounds of thick filament entry, egress and re-entry. Myosin mutations, particularly ones in the rod, could affect each step of myosin’s movement into and out of sarcomeres. We propose to use single myosin molecule imaging of WT and mutant myosins in genome edited hiPS muscle cells to measure these processes. Specifically, mutations in the same amino acid in the Type I/β cardiac myosin rod cause either a skeletal myopathy (R1500P) or a cardiomyopathy (R1500W). In mouse models of these mutations, we will use multi-isotope mass spectroscopy electron microscopy (MIMS-EM) technology to measure sarcomere homeostasis in WT mice as well as how it is affected by the R1500P and R1500W mutations.

项目概要 10个基因家族的多个成员中存在超过500个人类肌节肌球蛋白重链突变引起 11 种不同的心脏和骨骼肌疾病。肌球蛋白由球状运动结构域和 α- 组成。尽管研究了肌球蛋白基因家族，但螺旋杆结构域始终存在致病突变。多年来，我们最近发现了意想不到的生物学，例如哺乳动物中的“肌节”肌球蛋白大脑和内耳以及单个肌球蛋白分子进出肌节的快速运动。目标是了解肌球蛋白基因家族的多样化，不同的肌球蛋白如何驱动肌肉功能，以及同一肌球蛋白基因的相同残基的突变如何导致骨骼或心肌为了实现这些目标，我们提出综合结构、生物物理、细胞和体内。在横纹肌中发现了非正统的 MYH7b 蛋白。蟒蛇和鸟类，但只有少数哺乳动物的肌肉表达这种蛋白质。 Python 和人类 MYH7b 蛋白的功能，检验人类 MYH7b 蛋白具有的假设从蟒蛇中看到的典型肌节运动进化到其在特殊哺乳动物肌肉中的应用，其中它是肌节细胞，存在于大脑和内耳的一部分细胞中，它在内耳中的作用很有趣。 MYH7b 复合杂合突变与遗传性听力损失有关，我们将研究这些大多数哺乳动物肌肉表达丰富的 MYH7b RNA，由于其无法产生蛋白质。我们的假设（得到强有力的初步数据支持）是哺乳动物。非编码 MYH7b RNA 调节高表达的 I 型慢速骨骼/β 心肌肌球蛋白的表达。肌肉的肌球蛋白组成是动态的，已知可以驱动生理机能，但人们对此知之甚少。健康和疾病状态下肌球蛋白如何进出肌节肌球蛋白的半衰期更长。蛋白质（约 10 天）与其肌节替代率（5-14 小时）相比表明每个分子肌球蛋白突变，特别是杆，可能会影响肌球蛋白进出肌节的每一步，我们建议使用单一的。基因组编辑 hiPS 肌肉细胞中 WT 和突变型肌球蛋白的肌球蛋白分子成像，以测量这些具体来说，I/β 型心肌肌球蛋白杆中相同氨基酸的突变会导致以下任一过程。在这些突变的小鼠模型中，我们将使用骨骼肌病（R1500P）或心肌病（R1500W）。多同位素质谱电子显微镜 (MIMS-EM) 技术测量肌节 WT 小鼠的体内平衡以及 R1500P 和 R1500W 突变对其的影响。