Study of Cell Adhesion Through an Analysis of Myosin 7

通过肌球蛋白 7 的分析研究细胞粘附

• 批准号: 6445101
• 负责人: MARGARET A TITUS
• 金额: $ 26.99万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-08-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6445101
• 关键词: Dictyostelium; actins; balance; binding proteins; cell adhesion; gene deletion mutation; hearing; immunoprecipitation; intermolecular interaction; microorganism genetics; molecular genetics; myosins; polymerase chain reaction; protein binding; protein protein interaction; protein structure function; receptor binding; receptor expression

Myosin VII (M7) is an actin-based motor protein known to play an essential role in hearing and balance in humans, mice and zebrafish. The simple eukaryote Dictyostelium expresses a M7 homologue (DdM7) and null mutant analysis has revealed that it plays a critical role in cell substrate adhesion required for phagocytosis and cell migration, a novel function for a myosin. Emerging evidence from mammalian systems is consistent with M7's direct involve involvement in adhesion, indicating that the role of this class of myosins has been conserved throughout evolution. Our analysis of Ddm7 suggests that this myosin plays a role in organizing receptors into a high affinity complex (the adhesion complex) that is capable of binding to surfaces and is not involved in the transport of proteins to the plasma membrane. Furthermore, we have found that the tail region of Ddm7 is essential for the formation of this adhesion complex. The goal of our work is to identify the molecular basis of DdM7-based adhesion by answering the following major questions: 1) What are the proteins that link DdM7 to the adhesion complex? Both biochemical and genetic approaches will be used to identify proteins that bind to DdM7 and participate in cell adhesion; and 2) How do the linker proteins interact with DdM7 to make an adhesion complex. A complementation analysis will be employed to identify regions of the DdM7 molecule required for linking this myosin to the adhesion complex. Given the conservation of M7 function throughout evolution, the detailed molecular analysis of M7 function in a genetically tractable system such as Dictyostelium shall offer a unique opportunity to gain insight into how M7-based adhesion functions in the specialized cells of the auditory and vestibular system and how mutations in M7, such as occur in Usher's syndrome type IB, might lead to deafness.

肌球蛋白VII（M7）是一种基于肌动蛋白的运动蛋白，已知在人类，小鼠和斑马鱼中起着至关重要的作用。简单的真核生物Dictyostelium表达了M7同源物（DDM7），无效突变体分析表明，它在吞噬作用和细胞迁移所需的细胞底物粘附中起着关键作用，这是肌球蛋白的新功能。来自哺乳动物系统的新兴证据与M7的直接参与粘附一致，这表明这类肌动物的作用在整个进化过程中一直保存。我们对DDM7的分析表明，这种肌球蛋白在组织受体中的作用（粘附复合物）能够与表面结合，并且与蛋白质传输到质膜无关。此外，我们发现DDM7的尾部区域对于这种粘附复合物的形成至关重要。我们工作的目的是通过回答以下主要问题来确定基于DDM7的粘附的分子基础：1）将DDM7与粘附复合物联系起来的蛋白质是什么？生化方法和遗传方法都将用于鉴定与DDM7结合并参与细胞粘附的蛋白质。 2）接头蛋白如何与DDM7相互作用以使粘附复合物。将采用互补分析来确定将这种肌球蛋白与粘附络合物联系起来所需的DDM7分子的区域。鉴于在整个演化过程中保存M7功能，因此在遗传上可触发的系统（例如Dictyostelium）中对M7功能的详细分子分析将提供一个独特的机会，可以深入了解基于M7的粘附如何在听觉和前庭系统的专业单元格中函数如何在M7中以及如何在USHER syndrome syndrome type Ib中引起M7中的突变。