G Protein βγ Subunits Regulate Cell Adhesion through Rap1a and Its Effector Radil

The activation of several G protein-coupled receptors is known to regulate the adhesive properties of cells in different contexts. Here, we reveal that G beta gamma subunits of heterotrimeric G proteins regulate cell-matrix adhesiveness by activating Rap1a-dependent inside-out signals and integrin activation. We show that G beta gamma subunits enter in a protein complex with activated Rap1a and its effector Radil and establish that this complex is required downstream of receptor stimulation for the activation of integrins and the positive modulation of cell-matrix adhesiveness. Moreover, we demonstrate that G beta gamma and activated Rap1a promote the translocation of Radil to the plasma membrane at sites of cell-matrix contacts. These results add to the molecular understanding of how G protein-coupled receptors impinge on cell adhesion and suggest that the G beta gamma.Rap1.Radil complex plays important roles in this process.