Fife localizes to the active zone cytomatrix. (A) Single optical section (0.4 µm) of C155-Gal4/Y; UAS-RIM-GFP/+; UAS-FLAG-Fife/+ NMJ boutons colabeled with antibodies against GFP (green) and FLAG (purple). (B) Single optical section (1.2 µm) of a larval ventral ganglion homozygous for Fife endogenously tagged at an internal site common to all isoforms (Fife^Int-HA) and colabeled with antibodies against HA (green) and Bruchpilot (nc82, purple). (C) Single optical section (0.1 µm) of NMJ boutons homozygous for the same internal endogenous tag as in B and colabeled with antibodies against HA (green) and Bruchpilot (purple). (D) Single optical section (0.4 µm) of NMJ boutons homozygous for Fife endogenously tagged at the N-terminus (Fife^Nterm-GFP) and colabeled with antibodies against HA (green) and Bruchpilot (nc82, purple).