CK2α and CK2β localize to the presynaptic nerve terminal. (A and B) Analysis of endogenous CK2α localization. CK2α (green) is present within the presynaptic nerve terminal marked by Hrp (red; A). In CK2αP1/TikR mutant animals presynaptic CK2α staining is absent (B). (C–F) Analysis of the synaptic localization of GFP-tagged CK2α and CK2β. (C) GFP-tagged wild-type CK2α (green) localized to synaptic bouton and interbouton regions marked by the synaptic vesicle marker DvGlut (blue). (D) A comparable distribution was observed when GFP-CK2α was expressed in CK2α mutant animals. GFP-tagged CK2α completely restored synapse stability in these animals, indicating functional distribution. (E) Presynaptic CK2α localization did not depend on kinase activity. (F) Neuronal expression of GFP-tagged CK2β (green) resulted in a similar presynaptic localization. Bar, 5 µm.
