Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada.
J Cell Sci. 2013 Feb 1;126(Pt 3):722-31. doi: 10.1242/jcs.112375. Epub 2012 Dec 21.
Cells inversely adjust the plasma membrane levels of integrins and cadherins during cell migration and cell-cell adhesion but the regulatory mechanisms that coordinate these trafficking events remain unknown. Here, we demonstrate that the small GTPase Rab35 maintains cadherins at the cell surface to promote cell-cell adhesion. Simultaneously, Rab35 supresses the activity of the GTPase Arf6 to downregulate an Arf6-dependent recycling pathway for β1-integrin and EGF receptors, resulting in inhibition of cell migration and attenuation of signaling downstream of these receptors. Importantly, the phenotypes of decreased cell adhesion and increased cell migration observed following Rab35 knock down are consistent with the epithelial-mesenchymal transition, a feature of invasive cancer cells, and we show that Rab35 expression is suppressed in a subset of cancers characterized by Arf6 hyperactivity. Our data thus identify a key molecular mechanism that efficiently coordinates the inverse intracellular sorting and cell surface levels of cadherin and integrin receptors for cell migration and differentiation.
细胞在迁移和细胞间黏附中会反向调节质膜上整合素和钙黏蛋白的水平,但协调这些运输事件的调节机制尚不清楚。在这里,我们证明小 GTPase Rab35 将钙黏蛋白保持在细胞表面以促进细胞间黏附。同时,Rab35 抑制 GTPase Arf6 的活性,下调依赖于 Arf6 的β1 整合素和表皮生长因子受体的回收途径,从而抑制细胞迁移,并减弱这些受体下游的信号转导。重要的是,Rab35 敲低后观察到的细胞黏附减少和细胞迁移增加的表型与上皮-间充质转化一致,这是侵袭性癌细胞的特征,我们还表明,在一组以 Arf6 过度活跃为特征的癌症中,Rab35 的表达受到抑制。因此,我们的数据确定了一种关键的分子机制,该机制有效地协调了细胞迁移和分化过程中钙黏蛋白和整合素受体的反向细胞内分拣和细胞表面水平。