Filopodia assemble unique integrin-adhesion complexes to sense the extracellular matrix. However, the mechanisms of integrin regulation in filopodia are poorly defined. Here, we report that active integrins accumulate at the tip of myosin-X (MYO10)-positive filopodia, while inactive integrins are uniformly distributed. We identify talin and MYO10 as the principal integrin activators in filopodia. In addition, deletion of MYO10’s FERM domain, or mutation of its β1-integrin-binding residues, reveals MYO10 as facilitating integrin activation, but not transport, in filopodia. However, MYO10’s isolated FERM domain alone cannot activate integrins, potentially because of binding to both integrin tails. Finally, because a chimera construct generated by swapping MYO10-FERM by talin-FERM enables integrin activation in filopodia, our data indicate that an integrin-binding FERM domain coupled to a myosin motor is a core requirement for integrin activation in filopodia. Therefore, we propose a two-step integrin activation model in filopodia: receptor tethering by MYO10 followed by talin-mediated integrin activation.

丝状伪足组装独特的整合素-粘附复合物以感知细胞外基质。然而，丝状伪足中整合素调控的机制尚不明确。在这里，我们报告活性整合素聚集在肌球蛋白-X (MYO10) 阳性丝状伪足的尖端，而非活性整合素均匀分布。我们将 talin 和 MYO10 确定为丝状伪足中的主要整合素激活剂。此外，MYO10 的 FERM 结构域的缺失，或其 β1-整合素结合残基的突变，揭示了 MYO10 在丝状伪足中促进整合素激活，但不促进整合素的激活。然而，单独的 MYO10 分离的 FERM 结构域不能激活整合素，可能是因为与两个整合素尾部结合。最后，因为通过 talin-FERM 交换 MYO10-FERM 生成的嵌合体结构能够在丝状伪足中激活整合素，我们的数据表明，结合肌球蛋白马达的整合素结合 FERM 结构域是丝状伪足中整合素激活的核心要求。因此，我们提出了丝状伪足中的两步整合素激活模型：MYO10 的受体束缚，然后是 talin 介导的整合素激活。