The final serine residue (the third from the end) was mutated to alanine to prohibit PDZ protein (post synaptic density protein (PSD95, Dlg4), Drosophila disc large tumor suppressor (DlgA; Dlg1), and zonula occludens-1 protein (Zo-1; Tjp1)) binding. A residual loxP site is located in the 3' UTR after excision of a loxP-flanked neomycin cassette. (J:166050)