网格蛋白和肌动蛋白介导的内吞作用机制的模块化设计。

A modular design for the clathrin- and actin-mediated endocytosis machinery.

作者信息

Kaksonen Marko, Toret Christopher P, Drubin David G

机构信息

Department of Molecular and Cell Biology, University of California, Berkeley, 94720, USA.

出版信息

Cell. 2005 Oct 21;123(2):305-20. doi: 10.1016/j.cell.2005.09.024.

DOI:10.1016/j.cell.2005.09.024

PMID:16239147

Abstract

Endocytosis depends on an extensive network of interacting proteins that execute a series of distinct subprocesses. Previously, we used live-cell imaging of six budding-yeast proteins to define a pathway for association of receptors, adaptors, and actin during endocytic internalization. Here, we analyzed the effects of 61 deletion mutants on the dynamics of this pathway, revealing functions for 15 proteins, and we analyzed the dynamics of 8 of these proteins. Our studies provide evidence for four protein modules that cooperate to drive coat formation, membrane invagination, actin-meshwork assembly, and vesicle scission during clathrin/actin-mediated endocytosis. We found that clathrin facilitates the initiation of endocytic-site assembly but is not needed for membrane invagination or vesicle formation. Finally, we present evidence that the actin-meshwork assembly that drives membrane invagination is nucleated proximally to the plasma membrane, opposite to the orientation observed for previously studied actin-assembly-driven motility processes.

摘要

内吞作用依赖于一个由相互作用的蛋白质构成的广泛网络，这些蛋白质执行一系列不同的子过程。此前，我们利用对六种芽殖酵母蛋白的活细胞成像来定义内吞内化过程中受体、衔接蛋白和肌动蛋白的关联途径。在此，我们分析了61个缺失突变体对该途径动力学的影响，揭示了15种蛋白质的功能，并且我们分析了其中8种蛋白质的动力学。我们的研究为四个蛋白质模块提供了证据，它们在网格蛋白/肌动蛋白介导的内吞作用过程中协同驱动衣被形成、膜内陷、肌动蛋白网络组装和囊泡切割。我们发现网格蛋白促进内吞位点组装的起始，但膜内陷或囊泡形成并不需要它。最后，我们提供证据表明，驱动膜内陷的肌动蛋白网络组装在质膜近端成核，这与之前研究的肌动蛋白组装驱动的运动过程中观察到的方向相反。