Filopodia, a finger-like structure and actin-rich plasma-membrane protrusion at the leading edge of the cell, has important roles in cell motility. However, the mechanisms of filopodia generation are not well-understood via the actin-related protein 2/3 (ARP2/3) complex in Non-Small Cell Lung Cancer (NSCLC) cells. We previously have demonstrated that PRR11 associates with the ARP2/3 complex to regulate cytoskeleton-nucleoskeleton assembly and chromatin remodeling. In this study, we further demonstrate that PRR11 involves in filopodia formation, focal adhesion turnover and cell motility through ARP2/3 complex. Cell phenotype assays revealed that the silencing of PRR11 increased cellular size and inhibited cell motility in NSCLC cells. Mechanistically, PRR11 recruited and co-localized with Arp2 at the membrane protrusion to promote filopodia formation but not lamellipodia formation. Notably, PRR11 mutant deletion of the proline-rich region 2 (amino acid residues 185–200) abrogated the effect of filopodia formation. In addition, PRR11-depletion inhibited filopodial actin filaments assembly and increased the level of active integrin β1 in the cell surface, whereas reduced the phosphorylation level of focal adhesion kinase (FAK^Y397) to repress focal adhesion turnover and cell motility in NSCLC cells. Taken together, our findings indicate that PRR11 has critical roles in controlling filopodia formation, focal adhesion turnover and cell motility by recruiting ARP2/3 complex, thus dysregualted expression of PRR11 potentially facilitates tumor metastasis in NSCLC cells.

丝状伪足是一种指状结构和细胞前缘富含肌动蛋白的质膜突起，在细胞运动中具有重要作用。然而，通过非小细胞肺癌 (NSCLC) 细胞中的肌动蛋白相关蛋白 2/3 (ARP2/3) 复合物产生丝状伪足的机制尚不清楚。我们之前已经证明 PRR11 与 ARP2/3 复合物结合以调节细胞骨架-核骨架组装和染色质重塑。在这项研究中，我们进一步证明 PRR11 通过 ARP2/3 复合物参与丝状伪足形成、粘着斑周转和细胞运动。细胞表型分析显示，PRR11 的沉默增加了 NSCLC 细胞的细胞大小并抑制了细胞运动。机械地，PRR11 在膜突起处招募并与 Arp2 共定位，以促进丝状伪足的形成，但不促进片状伪足的形成。值得注意的是，富含脯氨酸的区域 2（氨基酸残基 185-200）的 PRR11 突变体缺失消除了丝状伪足形成的影响。此外，PRR11 耗竭抑制丝状肌动蛋白丝组装并增加细胞表面活性整合素 β1 的水平，而降低粘着斑激酶 (FAK) 的磷酸化水平^Y397 ) 抑制 NSCLC 细胞中的粘着斑更新和细胞运动。总之，我们的研究结果表明，PRR11 通过募集 ARP2/3 复合物在控制丝状伪足形成、粘着斑周转和细胞运动中起关键作用，因此 PRR11 的异常表达可能促进 NSCLC 细胞中的肿瘤转移。