Rice GDP dissociation inhibitor 3 inhibits OsMAPK2 activity through physical interaction

► OsGDI3 is a Rab-specific regulator and OsGDI3 interacts with OsMAPK2. ► OsGDI3 inhibits the autophosphorylation activity of OsMAPK2. ► OsGDI3 reduces kinase activity of plant MAPKs. ► OsGDI3 does not have dephosphorylation activity. ► SCR regions in OsGDI3 are necessary to the inhibition of OsMAPK2 activity and physical interaction with OsMAPK2.