Juanes M Angeles, Bouguenina Habib, Eskin Julian A, Jaiswal Richa, Badache Ali, Goode Bruce L
Department of Biology, Brandeis University, Waltham, MA
Centre de Recherche en Cancérologie de Marseille, Institut National de la Santé et de la Recherche Médicale, Institut Paoli-Calmettes, Aix-Marseille Université, Centre National de la Recherche Scientifique, Marseille, France.
J Cell Biol. 2017 Sep 4;216(9):2859-2875. doi: 10.1083/jcb.201702007. Epub 2017 Jun 29.
Cell motility depends on tight coordination between the microtubule (MT) and actin cytoskeletons, but the mechanisms underlying this MT-actin cross talk have remained poorly understood. Here, we show that the tumor suppressor protein adenomatous polyposis coli (APC), which is a known MT-associated protein, directly nucleates actin assembly to promote directed cell migration. By changing only two residues in APC, we generated a separation-of-function mutant, APC (m4), that abolishes actin nucleation activity without affecting MT interactions. Expression of full-length APC carrying the m4 mutation (APC (m4)) rescued cellular defects in MT organization, MT dynamics, and mitochondrial distribution caused by depletion of endogenous APC but failed to restore cell migration. Wild-type APC and APC (m4) localized to focal adhesions (FAs), and APC (m4) was defective in promoting actin assembly at FAs to facilitate MT-induced FA turnover. These results provide the first direct evidence for APC-mediated actin assembly in vivo and establish a role for APC in coordinating MTs and actin at FAs to direct cell migration.
细胞运动性取决于微管（MT）和肌动蛋白细胞骨架之间的紧密协调，但这种MT-肌动蛋白相互作用的潜在机制仍知之甚少。在这里，我们表明肿瘤抑制蛋白腺瘤性息肉病大肠杆菌（APC），一种已知的MT相关蛋白，直接促进肌动蛋白组装成核以促进细胞定向迁移。通过仅改变APC中的两个残基，我们产生了一个功能分离突变体，APC（m4），它消除了肌动蛋白成核活性而不影响MT相互作用。携带m4突变的全长APC（APC（m4））的表达挽救了由内源性APC耗竭引起的MT组织、MT动力学和线粒体分布中的细胞缺陷，但未能恢复细胞迁移。野生型APC和APC（m4）定位于粘着斑（FAs），并且APC（m4）在促进FAs处的肌动蛋白组装以促进MT诱导的FA周转方面存在缺陷。这些结果为体内APC介导的肌动蛋白组装提供了首个直接证据，并确立了APC在协调FAs处的MT和肌动蛋白以指导细胞迁移中的作用。
