GTPases Are Molecular Switches that Follow a Characteristic Cyclic Pattern (image) Aarhus University Share Print E-Mail Caption When a GTPase is bound to GTP (right), it is active or 'on'. In this state, the GTPase can bind to so-called effector molecules (below), which transmit the GTPase's signal further within the cell. The interaction with the effector causes the GTPase to hydrolyse the bound GTP, thereby rendering the GTPase to its inactive "off" GDP-bound form (left). The GTPase can be reactivated via interaction with a guanine-nucleotide exchange factor that promotes the replacement of the bound GDP with GTP (top). Credit Charlotte Rohde Knudsen Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. Share Print E-Mail Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.