Myosin-X and the molecular basis of filopodia function

肌球蛋白-X 和丝状伪足功能的分子基础

• 批准号: 7319196
• 负责人: RICHARD E CHENEY
• 金额: $ 29.88万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-06-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7319196
• 关键词: Actins; Animals; Biochemical; Biological Process; Biology; Biophysics; Blood Vessels; Calcium; Calmodulin; Cell physiology; Cells; Cellular biology; Class; Complex; Exhibits; Family; Filopodia; Green Fluorescent Proteins; Growth; Health; Hearing; Hearing Impaired Persons; Human; Inherited; Intracellular Transport; Knock-out; Knockout Mice; Lead; Length; Life; Light; Localized; Microfilaments; Modeling; Molecular; Motor; Movement; Mutation; Myosin ATPase; Neoplasm Metastasis; Nerve; Nerve Regeneration; Numbers; Phenotype; Physiological; Process; Property; Range; Rate; Regulation; Research; Research Personnel; Resolution; Role; Shapes; Signal Transduction; Signaling Molecule; Stereocilium; Structure; System; Testing; Tissues; Total Internal Reflection Fluorescent; Usher Syndrome; Virus; Work; angiogenesis; base; cancer cell; cell motility; cellular engineering; cellular microvillus; deafness; fluorescence imaging; gastrointestinal microvillus; human disease; member; novel; programs; protein function; sensor; tool

DESCRIPTION (provided by applicant): Filopodia are slender cellular extensions that appear to function as cellular sensors that allow cells to interact with their surroundings in processes such as nerve growth, blood vessel formation, and the metastasis of cancer cells. Despite the central importance of filopodia and related structures such as microvilli and stereocilia, the molecular mechanisms that regulate the formation and function of these structures remain unclear. Growing evidence indicates that the MyTH4-FERM myosins, a newly recognized family of unconventional myosins, have critical roles as motor proteins that function in filopodia and related structures. Humans express four MyTH4-FERM myosins and mutations in two of these lead to hereditary deafness. We have discovered that myosin-X, a vertebrate-specific member of the MyTH4-FERM myosins that localizes to the tips of filopodia, is a remarkably potent inducer of filopodia, and undergoes a novel form of motility within filopodia. This has led us to hypothesize that myosin-X functions as a motor for a previously unsuspected system of intracellular transport within filopodia and related structures. We thus propose to: 1) Determine the molecular mechanisms by which myosin-X induces filopodia. 2) Investigate the basic properties of the novel system of intrafilopodial motility we have discovered. 3) Isolate full-length myosin-X and determine its fundamental biochemical properties 4) Determine the cellular and organismal functions of myosin-X using a mouse knock-out. By investigating myosin-X, the MyTH4-FERM myosin that is expressed in most vertebrate cells and tissues, this research will provide a model to investigate the fundamental cell biology of the MyTH4-FERM myosins and their roles in filopodia-like structures. This research is particularly relevant to deafness, since hearing depends on stereocilia, filopodia-like mechanosensors that contain a core of actin filaments. In addition, mutations in at least five other unconventional myosins are already known to cause human deafness, including Usher syndrome 1b, the leading cause of hereditary deaf-blindness. There is also growing evidence that filopodia can act as cellular highways that transport materials such as key signaling molecules and viruses, so studies of myosin-X function in filopodia will contribute to our understanding of the fundamental cell biology underlying nerve regeneration, angiogenesis, and the spread of cancer cells.

描述（由申请人提供）：丝状伪足是细长的细胞延伸，似乎起到细胞传感器的作用，允许细胞在神经生长、血管形成和癌细胞转移等过程中与周围环境相互作用。尽管丝状伪足和微绒毛和静纤毛等相关结构具有核心重要性，但调节这些结构形成和功能的分子机制仍不清楚。越来越多的证据表明，MyTH4-FERM 肌球蛋白是一个新认识的非常规肌球蛋白家族，作为在丝状伪足和相关结构中发挥作用的运动蛋白，具有关键作用。人类表达四种 MyTH4-FERM 肌球蛋白，其中两种的突变会导致遗传性耳聋。我们发现肌球蛋白-X 是 MyTH4-FERM 肌球蛋白的脊椎动物特异性成员，定位于丝状伪足的尖端，是一种非常有效的丝状伪足诱导剂，并且在丝状伪足内经历一种新型形式的运动。这使我们推测肌球蛋白-X 可以充当丝状伪足和相关结构内先前未曾怀疑的细胞内运输系统的马达。因此，我们建议：1）确定肌球蛋白-X 诱导丝状伪足的分子机制。 2）研究我们发现的新型丝状足内运动系统的基本特性。 3) 分离全长肌球蛋白-X 并确定其基本生化特性 4) 使用小鼠基因敲除确定肌球蛋白-X 的细胞和组织功能。通过研究肌球蛋白-X（在大多数脊椎动物细胞和组织中表达的 MyTH4-FERM 肌球蛋白），本研究将提供一个模型来研究 MyTH4-FERM 肌球蛋白的基本细胞生物学及其在丝状伪足样结构中的作用。这项研究与耳聋尤其相关，因为听力依赖于静纤毛，即含有肌动蛋白丝核心的类似丝状伪足的机械传感器。此外，已知至少有五种其他非常规肌球蛋白的突变会导致人类耳聋，其中包括亚瑟综合征 1b，它是遗传性聋盲的主要原因。还有越来越多的证据表明，丝状伪足可以充当细胞高速公路，运输关键信号分子和病毒等物质，因此对丝状伪足中肌球蛋白-X功能的研究将有助于我们了解神经再生、血管生成和癌细胞扩散的基础细胞生物学。