Mechanism of myosin motor-dependent filopodia formation

设备管理补充-GM 122917 Margaret A. Titus，PI 父项目摘要 在组织中迁移的细胞，包括癌细胞，使用丝状伪足引导它们通过3D环境 丝状伪足形成的增加与肿瘤的转移潜能和侵袭性密切相关。 癌细胞丝状伪足是由交联的平行肌动蛋白组成的细长的、充满肌动蛋白的突起 捆起来。它们是高度动态的，长度不同，并在各种细胞类型中发现，如神经元 利用它们进行梯度感应和有效的定向迁移， 从肿瘤转移到邻近组织。 丝状伪足形成的第一步还不太清楚。需要三种保守的蛋白质 它们的形成-MyTH 4-FERM肌球蛋白（MF; MyTH 4 =肌球蛋白尾同源性4; FERM =条带4.1，埃兹蛋白， radixin，膜突蛋白）和两种肌动蛋白聚合调节剂，VASP和Formin。这三个人的行动 蛋白质协调启动丝状伪足形成是未知的。父项目的目标是 定义丝状伪足起始的分子机制，强调MF肌球蛋白在其中的作用， 过程多功能模型系统，Dictyosteoblastoma将用于定义MF肌球蛋白和VASP如何工作 一起组织在膜上的肌动蛋白丝的快速生长末端以引发聚合。一 将采用体内、体外和计算机模拟方法的组合来a）确定功能性的 a）MF肌球蛋白、VASP和肌球蛋白之间的关系，B）鉴定肌球蛋白马达的特定性质 用于丝状伪足起始，c）鉴定与MF肌球蛋白相互作用以促进皮质靶向的蛋白质 在丝状足起始和丝状足尖端形成期间，以及d）开发随机计算模型， 预测能力，将告知实验目标，其结果将用于完善模型。 母项目产生的知识将揭示细胞如何使用肌球蛋白为基础的马达来构建 特殊的肌动蛋白结构，如丝状伪足。了解启动是如何发生的也将揭示细胞如何 控制丝状伪足的形成，使其能够定向迁移或侵入周围组织。

Administrative Supplement for Equipment - GM122917 Margaret A. Titus, PI Abstract of Parent Project Cells migrating in tissues, including cancer cells, use filopodia to guide them through the 3D environment and increased formation of filopodia correlates strongly with the metastatic potential and invasiveness of cancer cells. Filopodia are slender actin-filled projections composed of a core of cross-linked, parallel actin bundles. They are highly dynamic, vary in length and are found in a wide variety of cell types such as neurons that use them for gradient sensing and efficient directional migration and cancer cells that employ them for moving out from tumors into neighboring tissue. The first steps of filopodia formation are not well understood. Three conserved proteins are required for their formation - a MyTH4-FERM myosin (MF; MyTH4 = myosin tail homology 4; FERM = band 4.1, ezrin, radixin, moesin) and two regulators of actin polymerization, VASP and Formin. How the action of these three proteins is coordinated to initiate filopodia formation is unknown. The objective of the parent project is to define the molecular mechanism of filopodia initiation with an emphasis on the role of a MF myosin in this process. The versatile model system, Dictyostelium will be used to define how a MF myosin and VASP work together to organize the fast growing ends of actin filaments at the membrane to initiate polymerization. A combination of in vivo, in vitro and in silico approaches will be employed to a) determine the functional relationship between a MF myosin, VASP and formin, b) identify the specific properties of the myosin motor used for filopodia initiation, c) identify proteins that interact with the MF myosin to promote cortical targeting during filopod initiation and filopod tip formation and d) develop a stochastic computational model with predictive power that will inform the experimental goals, the results of which will be used to refine the model. The knowledge generated by the parent project will reveal how cells use a myosin-based motor to build specific actin-based structures such as filopodia. Understanding how initiation occurs will also reveal how cells control filopodia formation to enable directed migration or invasion of surrounding tissues.