signal By Ivan Suarez Robles 15 Nov, 2010 A protein in a molecular pathway that can activate or deactivate another protein.Related Articles: Stories of HOPES: "Bryan's Dad Plays the Game"Maladies of My Mind - Ch. 1 Father's Praying RoomMaladies of My Mind - Ch. 3 DrowningHelp4HD Second Annual Symposium13th Annual Huntington Disease Research Symposium