Two types of intracellular signaling proteins that act as Molecular Switches SIGNAL OFF SIGNAL OFF IN IN GDP ATP protein protein GDP GTP GTP kinase phosphatase GTP binding hydrolysis ADP ON ON GTP SIGNAL SIGNAL OUT OUT (A)SIGNALING BY PHOSPHORYLATION (B) SIGNALING BY GTP-BINDING This document is produced by trial version of Print2Flash.Visit www.print2flash.com for more information