Mechanism of myosin motor-dependent filopodia formation

上级项目摘要 在组织中迁移的细胞，包括癌细胞，使用丝状足引导它们通过3D 环境和丝状足的形成与转移密切相关。 癌细胞的潜能和侵袭力。丝状足是细长的充满肌动蛋白的突起。 由交叉连接的、平行的肌动蛋白束组成的核心。它们是高度动态的，在不同的 在各种各样的细胞类型中都有发现，比如用它们来进行梯度的神经元 感知和有效的定向迁移以及利用它们向外移动的癌细胞 从肿瘤转移到邻近组织。 丝状孢子形成的第一步还不是很清楚。三种保守的蛋白质是 形成它们所需的-MyTH4-ferm肌球蛋白(Mf；MyTH4=肌球蛋白尾部同源4； FERM=带4.1，Ezrin，Radix，moesin)和两个肌动蛋白聚合调节因子，Vasp和 福明。这三种蛋白质是如何协调作用来启动丝状足的形成的 未知。母项目的目标是确定丝状伪足的分子机制 启动，强调肌球蛋白在这一过程中的作用。多功能机型 系统中，将使用Dictyostelials来定义MF肌球蛋白和VASP如何协同工作 在膜上组织肌动蛋白细丝快速生长的末端，以启动聚合。一个 将采用体内、体外和硅胶方法相结合的方法来确定a) 肌球蛋白、血管活性蛋白和福尔明之间的功能关系，b)识别特定的 用于丝状足起始的肌球蛋白马达的性质，c)识别与 肌球蛋白在丝足启动和丝足尖端形成过程中促进皮质靶向 D)开发具有预测能力的随机计算模型，该模型将向 实验目标，其结果将被用来改进模型。 母项目产生的知识将揭示细胞如何使用基于肌球蛋白的 运动，以建立特定的肌动蛋白为基础的结构，如丝状足。了解印心如何 还将揭示细胞如何控制丝状足的形成，以实现定向迁移或 侵入周围组织。

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.