ZAKisamemberoftheMAPKKKfamilyofsignaltransductionmoleculesandmediatesgammar
ADIationsignalingleadingtocellcyclearrest.TheactivityofZAKplaysaroleincellcyclecheckpointregulationaswellasbeinginvolvedinregulatingactinorganization(1).Expressionofkinase-deadZAKinmousefibroblastsdisruptsactinstressfibersandcausesmorphologicchanges.ZAKcanactivateJNKthroughMKK4/MKK7andERK5/p38-gammaviaMKK3/MKK6.ExpressionofZAKincreasesthepopulationofcellsintheG2/Mphaseofthecellcycle,whereasdominant-negativeZAKattenuatedtheG2arrestcausedbygammaradiation(2).