Sechi Antonio S, Wehland Juergen
Department of Cell Biology, Gesellschaft fuer Biotechnologische Forschung, Mascheroder Weg, 1a, D-38124 Braunschweig, Germany.
Front Biosci. 2004 May 1;9:1294-310. doi: 10.2741/1324.
The spatial and temporal regulation of the actin cytoskeleton is fundamental to several cellular processes as diverse as cell motility and immune responses. At the molecular level, the remodelling of the actin cytoskeleton depends on two key events: actin filament nucleation and elongation. Seminal studies on the actin-based intracellular motility of the bacterial pathogen Listeria monocytogenes have been instrumental for the characterisation of a class of actin filament elongating factors, the proteins of the Ena/VASP family. Ena/VASP proteins enhance actin filament elongation via the recruitment of profilin:actin complexes to sites of active actin remodelling such as the tips of spreading lamellipodia and the surface of intracellular Listeria. Moreover, Ena/VASP proteins not only enhance actin filament elongation but also influence the activity of the Arp2/3 complex and counteract the inhibition of actin polymerisation by capping proteins. These findings, taken together with the observation that Ena/VASP proteins can influence actin filament architecture by affecting the actin filament branching activity of the Arp2/3 complex, define Ena/VASP proteins as multifunctional organisers of the actin cytoskeleton.
肌动蛋白细胞骨架的时空调节对于多种细胞过程至关重要，这些过程包括细胞运动和免疫反应等。在分子水平上，肌动蛋白细胞骨架的重塑依赖于两个关键事件：肌动蛋白丝的成核和延伸。对细菌病原体单核细胞增生李斯特菌基于肌动蛋白的细胞内运动的开创性研究，对于一类肌动蛋白丝延伸因子（Ena/VASP家族蛋白）的表征起到了重要作用。Ena/VASP蛋白通过将肌动蛋白结合蛋白：肌动蛋白复合物招募到活跃的肌动蛋白重塑位点，如伸展的片状伪足尖端和细胞内李斯特菌的表面，来增强肌动蛋白丝的延伸。此外，Ena/VASP蛋白不仅增强肌动蛋白丝的延伸，还影响Arp2/3复合物的活性，并抵消帽蛋白对肌动蛋白聚合的抑制作用。这些发现，连同Ena/VASP蛋白可通过影响Arp2/3复合物的肌动蛋白丝分支活性来影响肌动蛋白丝结构的观察结果，将Ena/VASP蛋白定义为肌动蛋白细胞骨架的多功能组织者。
