Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany.
CytoMorphoLab, Laboratoire de Physiologie cellulaire et Végétale, Interdisciplinary ResearchInstitute of Grenoble, CEA, CNRS, INRA, Grenoble-Alpes University, Grenoble, France.
Elife. 2020 May 11;9:e55351. doi: 10.7554/eLife.55351.
Cell migration entails networks and bundles of actin filaments termed lamellipodia and microspikes or filopodia, respectively, as well as focal adhesions, all of which recruit Ena/VASP family members hitherto thought to antagonize efficient cell motility. However, we find these proteins to act as positive regulators of migration in different murine cell lines. CRISPR/Cas9-mediated loss of Ena/VASP proteins reduced lamellipodial actin assembly and perturbed lamellipodial architecture, as evidenced by changed network geometry as well as reduction of filament length and number that was accompanied by abnormal Arp2/3 complex and heterodimeric capping protein accumulation. Loss of Ena/VASP function also abolished the formation of microspikes normally embedded in lamellipodia, but not of filopodia capable of emanating without lamellipodia. Ena/VASP-deficiency also impaired integrin-mediated adhesion accompanied by reduced traction forces exerted through these structures. Our data thus uncover novel Ena/VASP functions of these actin polymerases that are fully consistent with their promotion of cell migration.
细胞迁移需要网络和束状肌动蛋白丝，分别称为片状伪足和微刺或丝状伪足，以及粘着斑，所有这些都招募了以前被认为拮抗有效细胞运动的 Ena/VASP 家族成员。然而，我们发现这些蛋白质在不同的小鼠细胞系中作为迁移的正调节剂发挥作用。CRISPR/Cas9 介导的 Ena/VASP 蛋白缺失减少了片状伪足的肌动蛋白组装，并扰乱了片状伪足的结构，这表现在网络几何形状的改变，以及纤维长度和数量的减少，伴随着异常的 Arp2/3 复合物和异二聚体盖帽蛋白的积累。Ena/VASP 功能的丧失也取消了通常嵌入片状伪足的微刺的形成，但不能形成没有片状伪足的丝状伪足。Ena/VASP 缺陷也损害了整合素介导的粘附，同时通过这些结构施加的牵引力减小。因此，我们的数据揭示了这些肌动蛋白聚合酶的新型 Ena/VASP 功能，这完全符合它们促进细胞迁移的作用。
