Zoological Institute, Braunschweig University of Technology, Spielmannstrasse 7, 38106 Braunschweig, Germany; Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
Zoological Institute, Braunschweig University of Technology, Spielmannstrasse 7, 38106 Braunschweig, Germany; Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany.
Curr Opin Cell Biol. 2019 Feb;56:53-63. doi: 10.1016/j.ceb.2018.09.004. Epub 2018 Oct 1.
Cell migration entails a plethora of activities combining the productive exertion of protrusive and contractile forces to allow cells to push and squeeze themselves through cell clumps, interstitial tissues or tissue borders. All these activities require the generation and turnover of actin filaments that arrange into specific, subcellular structures. The most prominent structures mediating the protrusion at the leading edges of cells include lamellipodia and filopodia as well as plasma membrane blebs. Moreover, in cells migrating on planar substratum, mechanical support is being provided by an additional, more proximally located structure termed the lamella. Here, we systematically dissect the literature concerning the mechanisms driving actin filament nucleation and elongation in the best-studied protrusive structure, the lamellipodium. Recent work has shed light on open questions in lamellipodium protrusion, including the relative contributions of nucleation versus elongation to the assembly of both individual filaments and the lamellipodial network as a whole. However, much remains to be learned concerning the specificity and relevance of individual factors, their cooperation and their site-specific functions relative to the importance of global actin monomer and filament homeostasis.
细胞迁移需要一系列的活动，包括有效地发挥伸出和收缩的力量，使细胞能够通过细胞团、间质组织或组织边界推动和挤压自己。所有这些活动都需要产生和转换肌动蛋白丝，这些肌动蛋白丝排列成特定的亚细胞结构。在细胞前缘介导突出的最突出的结构包括片状伪足和丝状伪足以及质膜泡。此外，在在平面基底上迁移的细胞中，由另一个更靠近的结构称为片层提供机械支撑。在这里，我们系统地分析了文献中关于在研究最深入的突起结构——片状伪足中驱动肌动蛋白丝成核和延伸的机制。最近的工作揭示了片状伪足突出的一些悬而未决的问题，包括成核与延伸对单个纤维和整个片状伪足网络组装的相对贡献。然而，关于单个因素的特异性和相关性、它们的合作以及它们相对于全局肌动蛋白单体和纤维动态平衡的重要性的特定功能，仍有许多需要了解。
