The Rho GTPase Rnd1 suppresses mammary tumorigenesis and EMT by restraining Ras-MAPK signalling

Giancotti and colleagues report that the Rnd1 Rho GTPase suppresses the epithelial–mesenchymal transition and mammary tumorigenesis by inhibiting Ras-MAPK signalling through a Plexin B1–Rap1–p120 Ras-GAP signalling axis.