Proteins Interacting in Myosin Assembly

肌球蛋白组装中相互作用的蛋白质

• 批准号: 6874887
• 负责人: HENRY F. EPSTEIN
• 金额: $ 36.62万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2008-03-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6874887
• 关键词: Proteins; Interacting; Myosin; Assembly

DESCRIPTION (provided by applicant): The myosins function as protein motors of the actin cytoskeleton in fundamental biological activities including cell division (cytokinesis), plasma membrane dynamics and vesicle trafficking as well as more specialized physiological roles including cardiac and skeletal muscle contraction. A newly identified family of proteins containing UCS-domains (U: unc-45; C: Cro-1; S: She4p) is expressed in eukaryotic organisms from yeast to humans and has been implicated in myosin assembly and function. In animals from Caenorhabditis elegans to humans, two additional protein regions are conserved: an NH2-terminal TPR-domain (Tetratrico Peptide Repeat), which is responsible for binding Hsp90, a molecular chaperone implicated in protein folding. The central region together with the COOH-UCS-domain is sufficient for myosin binding and chaperone activity. The animal proteins are generically termed UNC-45 after the canonical C. elegans molecule. To further understand both the mechanisms by which UNC-45 machines work and the finding in mice and humans of general cell and striated muscle isoforms, we propose the following Specific Aims: 1) What mechanisms operate in UNC-45 activity as a chaperone and as a Hsp90 co-chaperone in myosin S1 folding, full-length myosin assembly, or myosin motor-related activity? 2) What are the structure-function relationships between identified regions of UNC-45 and specific sites within them and their interactions with Hsp90 for myosin S1 folding, full-length myosin assembly, or myosin motor-related activity? 3) What are the functional consequences of the differences in amino acid sequences and patterns of expression between the general cellular and striated muscle isoforms of UNC-45 in mammals? To answer these questions, we will use wild type and mutant recombinant UNC-45 proteins of C. elegans and mice and specific mouse knockout lines. The understanding of these questions is likely to have broad significance not only to multiple problems in cell biology but also with respect to disease. The findings that UNC-45 fungal homologues are necessary for cytokinesis suggests that the UNC-45 general cell isoform may be important in relation to the dysregulation of cell division of cancer. The defective assembly of myosin into filaments by unc-45 mutants in C. elegans suggests that the UNC-45 striated muscle isoform may be important in heart failure and skeletal muscle atrophy in which the contractile machinery is dysfunctional or deficient.

描述（由申请人提供）：肌球蛋白在基本生物学活动（包括细胞分裂（胞质分裂）、质膜动力学和囊泡运输）以及更专门的生理学作用（包括心肌和骨骼肌收缩）中作为肌动蛋白细胞骨架的蛋白马达发挥作用。 一个新鉴定的含有UCS结构域的蛋白质家族（U：unc-45; C：Cro-1; S：She 4p）在从酵母到人类的真核生物中表达，并且已经涉及肌球蛋白组装和功能。 在从秀丽隐杆线虫到人类的动物中，两个额外的蛋白质区域是保守的：一个NH 2末端TPR结构域（Tetratrico Peptide Repeat），负责结合Hsp 90，一种涉及蛋白质折叠的分子伴侣。 中心区域连同COOH-UCS-结构域足以用于肌球蛋白结合和分子伴侣活性。 这种动物蛋白质在标准的C. elegans分子为了进一步了解β-45机器的工作机制以及在小鼠和人类中发现的一般细胞和横纹肌亚型，我们提出了以下具体目标：1）β-45作为伴侣蛋白和作为Hsp 90辅助伴侣蛋白在肌球蛋白S1折叠、全长肌球蛋白组装或肌球蛋白运动相关活性中的作用机制是什么？ 2)在肌球蛋白S1折叠、全长肌球蛋白组装或肌球蛋白运动相关活动中，Hsp 90与Hsp 45的识别区域和特定位点之间的结构-功能关系是什么？ 3)哺乳动物中α-45的一般细胞和横纹肌同种型之间的氨基酸序列和表达模式的差异有什么功能后果？ 为了回答这些问题，我们将使用C.线虫和小鼠以及特定的小鼠敲除系。对这些问题的理解可能不仅对细胞生物学中的多个问题而且对疾病具有广泛的意义。发现α-45真菌同系物是胞质分裂所必需的，表明α-45一般细胞同种型可能与癌症细胞分裂的失调有关。unc 45突变体在C. Elegans提出，β-45横纹肌同种型在心力衰竭和骨骼肌萎缩中可能是重要的，其中收缩机制功能障碍或缺陷。