The synaptic overgrowth at the neuromuscular junction seen in third instar larvae lacking Cdk5 function (Df(2R)Exel9026 homozygotes with all deleted gene functions except Cdk5 restored using P{Flo-1wt.Cdk5Δ.CG30466wt.CG8204wt}) is rescued by expression of Cdk5Scer\UAS.P\T.cKa under the control of either Scer\GAL4D42 or Scer\GAL4elav.PLu but is not rescued by expression under the control of Scer\GAL4Mhc.PW.