D4-GDI(GDPdissociationinhibitor)isanegativeregulatoroftherasrelatedRhoFamilyofGTPases.SincetherhoGTPasespromotecytoskeletalandmembranechangesassociatedwithapoptoticcelldeath,theremovaloftheD4-GDIblockthroughitscleavageisimportantforinducingapoptosis.Caspase-3cleavesthe28kDamatureformofD4-GDItogivea5kDaand23kDaSizefragment.The23kDafragmentthentranslocatestothenucleus.ThemechanismsinvolvingcleavageofD4-GDIwithapoptosisarenotpresentlyknown.ActivationoftheJunN-Terminalkinase,aregulatorofapoptosis,maybeoneofthemechanisms. Contributor:SujaySinghandPeterDias REFERENCES: