Nitric oxide cell signaling: S-nitrosation of Ras superfamily GTPases.

The Ras superfamily of small GTPases cycle between inactive GDP-bound and active GTP-bound states to modulate a diverse array of processes involved in cellular growth control. While the basic mechanisms by which GTPase regulatory proteins regulate GTPase substrates have been revealed through numerous studies, detailed studies into the mechanism(s) of free radical-mediated GTPase regulation have only more recently been tackled. This article reviews the mechanism of free radical-mediated GTPase regulation and shows nitric oxide can serve as important regulator of small GTPase proteins (i.e. Ras and RhoA) through protein modifications such as S-nitrosation.