Eukaryotic cells use actin polymerization to change shape, move, and internalize extracellular materials by phagocytosis and endocytosis, and to form contractile structures. In addition, several pathogens have evolved to use host cell actin assembly for attachment, internalization, and cell-to-cell spread. Although cells possess multiple mechanisms for initiating actin polymerization, attention in the past five years has focused on the regulation of actin nucleation-the formation of new actin filaments from actin monomers. The Arp2/3 complex and the multiple nucleation-promoting factors (NPFs) that regulate its activity comprise the only known cellular actin-nucleating factors and may represent a universal machine, conserved across eukaryotic phyla, that nucleates new actin filaments for various cellular structures with numerous functions. This review focuses on our current understanding of the mechanism of actin nucleation by the Arp2/3 complex and NPFs and how these factors work with other cytoskeletal proteins to generate structurally and functionally diverse actin arrays in cells.

中文翻译：

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肌动蛋白成核的细胞控制。

真核细胞利用肌动蛋白聚合反应通过吞噬作用和内吞作用改变细胞外物质的形状，移动和内在化，并形成收缩结构。另外，一些病原体已经进化为使用宿主细胞肌动蛋白装配体进行附着，内在化和细胞间扩散。尽管细胞具有多种引发肌动蛋白聚合的机制，但在过去的五年中，注意力集中在肌动蛋白成核的调控上-由肌动蛋白单体形成新的肌动蛋白丝。Arp2 / 3复合物和调节其活性的多个成核促进因子（NPF）构成了唯一已知的细胞肌动蛋白成核因子，可能代表了一个在真核生物门中保守的通用机器，该机器为各种细胞结构成核了新的肌动蛋白丝。众多功能。