Actin/myosin function in intracellular vesicle transport processes

肌动蛋白/肌球蛋白在细胞内囊泡转运过程中的功能

• 批准号: 355436594
• 负责人: Professor Dr. Eugen Kerkhoff
• 金额: --
• 依托单位: Labor Molekulare Zellbiology (Kerkhoff Lab)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/355436594?language=en
• 关键词: Actin; myosin; function; intracellular; vesicle

Directional membrane transport is the basis of eukaryotic cell organisation and polarisation. A combined transport along microtubule and actin filament tracks allows a specified delivery of molecules in space and time. The Rab11 GTPase is a master regulator of intracellular transport processes of the exocytic and recycling pathways and thereby a key function in the regulation of cell surface protein expression. Acting as a molecular switch, Rab11 builds distinct motor protein complexes at vesicle and endosomal membranes, which enable kinesin and dynein mediated fast and long-range transport along microtubules, as well as slower and local transport by myosin V actin motor proteins along actin filaments.Our recent discovery that Spir actin nucleators and myosin V assemble with Rab11 into a tripartite complex at vesicle membranes indicates a coordinated nucleation of actin filament tracks and myosin force generation on a subset of Rab11 vesicles. This enables actin/MyoV-driven motility in regions of the cell distal from the cortical actin network, such as in the oocyte cytoplasm and most likely in the central region of somatic cells. Based on live cell imaging data showing frequent nanotube formations of Spir/Rab11 vesicles, we propose a model in which the Spir and MyoV cooperation provides forces for vesicular morphological dynamics, which facilitates the attachment of vesicles to microtubule tracks for long-range transport.Novel genome editing technologies should be employed to specifically impair or modify Spir and MyoV functions in mouse fibroblast cells. Fluorescent protein tagged Spir, MyoV and Rab11 should be expressed under the control of their endogenous promoters. Modern fluorescence live cell imaging technologies will then enable us to monitor Rab11 vesicles and correlate morphological dynamics and motility to Spir and MyoV functions.The study proposed here should provide basic knowledge on the yet poorly understood functions of actin/myosin forces in intracellular vesicle transport processes and should thereby be elementary for subsequent mechanistic analysis of cell biological processes depending on these functions, such as the surface expression of adhesion molecules and growth factor receptors.

定向膜转运是真核细胞组织和极化的基础。沿着微管和肌动蛋白丝轨道的联合运输允许在空间和时间上特定的分子递送。Rab11 GTPase是胞外和循环途径的细胞内运输过程的主要调节剂，因此在调节细胞表面蛋白表达中起关键作用。作为分子开关，Rab11在囊泡和内体膜上构建不同的运动蛋白复合物，使运动蛋白和动力蛋白介导的沿着微管的快速和远程运输，以及肌凝蛋白V肌动蛋白运动蛋白沿着肌动蛋白丝的缓慢和局部运输成为可能。我们最近发现Spir肌动蛋白核子和肌凝蛋白V与Rab11在囊泡膜上组装成一个三边复合体，这表明在Rab11囊泡的一个子集上，肌动蛋白丝轨迹和肌凝蛋白力的协调成核。这使得肌动蛋白/ myov驱动的运动发生在远离皮质肌动蛋白网络的细胞区域，如卵母细胞细胞质，很可能发生在体细胞的中心区域。基于显示Spir/Rab11囊泡频繁形成纳米管的活细胞成像数据，我们提出了一个Spir和MyoV合作为囊泡形态动力学提供力量的模型，这有助于囊泡附着在微管轨道上进行远程运输。应该采用新的基因组编辑技术来特异性地破坏或修饰小鼠成纤维细胞中的Spir和MyoV功能。标记Spir、MyoV和Rab11的荧光蛋白应在其内源性启动子的控制下表达。现代荧光活细胞成像技术将使我们能够监测Rab11囊泡，并将形态动力学和运动性与Spir和MyoV功能相关联。这里提出的研究应该提供关于肌动蛋白/肌球蛋白力在细胞内囊泡运输过程中尚未了解的功能的基本知识，因此应该为后续依赖于这些功能的细胞生物学过程的机制分析提供基础，例如粘附分子和生长因子受体的表面表达。