Phosphatidylinositol 5-phosphate regulates invasion through binding and activation of Tiam1

Phosphatidylinositol 5-phosphate (PtdIns5P) is known to induce actin depolymerisation and cell migration; however, the mechanisms by which this occurs remain unclear. Viaud et al. show that PtdIns5P regulates actin dynamics and invasiveness by recruiting and activating the Rac-GTPase exchange factor Tiam1.