Intermediate Filaments & Costamere Structure & Function

中间丝

• 批准号: 7590621
• 负责人: ROBERT J BLOCH
• 金额: $ 38.54万
• 依托单位: UNIVERSITY OF MARYLAND BALTIMORE
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7590621
• 关键词: Actins; Address; Affect; Animals; Anterior; Behavior; Binding; Biomechanics; Biopsy; Cardiac; Cell membrane; Complex; Creatine Kinase; Desmin; Dystrophin; Elements; Extracellular Matrix; Fiber; Figs - dietary; Filament; Generations; Genetic; Glycoproteins; Heart; Human; In Situ; Individual; Injury; Intermediate Filament Proteins; Intermediate Filaments; KRT19 gene; Keratin; Keratin-19; Knock-out; Knockout Mice; Lead; Learning; Ligands; Link; Measures; Mechanics; Membrane; Microfilaments; Mitochondria; Molecular; Morphology; Mus; Muscle; Muscle Cells; Muscle Fibers; Muscular Dystrophies; Mutant Strains Mice; Mutation; Myocardium; Myofibrils; Myopathy; Nature; Organelles; Pathway interactions; Physiology; Play; Predisposition; Property; Proteins; Research; Role; Running; Sarcolemma; Sarcomeres; Secure; Serum; Severity of illness; Skeletal Muscle; Skeletal muscle injury; Striated Muscles; Structure; Surface; System; Testing; Work; base; dystrobrevin; flexor digitorum brevis; homologous recombination; mutant; null mutation; overexpression; protein complex; research study; response; skeletal; syncoilin; synemin

Costameres are structures at the surface of striated muscle that align the sarcolemma regularly with nearby myofibrils and transmit contractile force laterally, through the membrane to the extracellular matrix. Costameres must therefore be linked to nearby structures firmly enough to withstand the forces of contraction. Here we focus on links between costameres and myofibrils. Desmin-based and keratin-based intermediate filaments (IFs), as well as actin microfilaments, link superficial myofibrils to costameres at the sarcolemma. We postulate that IFs containing keratins 8 and 19 play an important role at costameres because, unlike desmin, they are found at all costameric structures. We have shown that K8/K19 IFs interact with the dystrophin- glycoprotein complex via K19, and that over-expression of K19 or elimination of K19 by homologous recombination disrupts costameres. The K19-null mutation in mice also leads to mitochondrial mislocalization, increased serum creatine kinase levels and reduced contractile force, suggesting that the absence of IFs containing K19 causes a mild skeletal myopathy. We now have mice in the same genetic background as the K19-null (FVB) that lack desmin, and that lack both K19 and desmin. Here we propose 5 aims to test the hypothesis that K19-based IFs together with desmin IFs form distinct but complementary links between the contractile apparatus and costameres in healthy muscle. We further propose that their absence either alone or together leads to a weakening of the links between costameres and the contractile apparatus, compromised muscle physiology, and increased susceptibility to injury induced by lengthening ("eccentric") contractions. Aim1 addresses the morphological changes in costameres, sarcomeres and intracellular organelles, including mitochondria, in K19-null, desmin-null, and double knock-out (DKO) mice. In Aim 2, we will characterize the contractile activity, running ability, and susceptibility to eccentric injury of the individual mutants and the DKO. Aim 3 addresses the biomechanical properties of muscles lacking K19, desmin or both IF proteins, by investigating the strength of connections between myofibrils, and between myofibrils and the sarcolemma. Our results should therefore elucidate the molecular pathways that transmit force in healthy muscle, and how the absence of IFs can lead to muscle disease.

COSTAMERES是在横纹肌肉表面的结构，该结构定期与附近的肌原纤维对齐，并通过膜横向传输收缩力到细胞外基质。因此，Costameres必须与附近的结构相连，以承受收缩力。在这里，我们专注于Costameres和肌原纤维之间的联系。基于Desmin的基于DeSmin的和基拉蛋白的中间丝（IFS）以及肌动蛋白的微丝，将浅表肌原纤维与肌膜上的Costameres联系起来。我们假设IF含有角蛋白8和19的IF在Costameres中起着重要作用，因为与Desmin不同，它们在所有Costameric结构中都被发现。我们已经表明，K8/K19 IFS通过K19与肌营养不良的糖蛋白复合物相互作用，并且通过同源重组对K19的过表达或消除K19会破坏Costameres。小鼠中的K19无效突变还导致线粒体错误定位，血清肌酸激酶水平增加并减少收缩力，这表明缺乏含有K19的IFS会导致轻度的骨骼肌病。现在，我们的小鼠与缺乏脱敏的K19-null（FVB）相同的遗传背景，并且缺乏K19和Desmin。在这里，我们提出5个旨在检验以下假设：基于K19的IF与Desmin IFS一起形成了健康肌肉中收缩仪和Costameres之间的不同但互补的联系。我们进一步提出，它们单独或共同缺席会导致Costameres与收缩式设备之间的联系，肌肉生理损害以及增加因延长（“偏心”）收缩引起的伤害的易感性。 AIM1解决了Costameres，肉瘤和细胞内细胞器的形态变化，包括线粒体，K19-Null，Desmin-Null和Double Dockning（DKO）小鼠。在AIM 2中，我们将表征收缩活动，跑步能力以及对单个突变体和DKO偏心损伤的敏感性。 AIM 3通过研究肌原纤维之间以及肌原纤维与肌膜中之间的连接强度，解决了缺乏K19，Desmin或IF蛋白质的肌肉的生物力学特性。因此，我们的结果应阐明在健康肌肉中传递力的分子途径，以及IFS缺乏如何导致肌肉疾病。