Colocalization of TMEM16A and TRPV6 in epididymal principal cells. (A and B) Confocal projections of serial stack images showing the double-immunofluorescent labeling for TMEM16A (red) and TRPV6 (green). The merged panels show that TMEM16A colocalizes with TRPV6 in the apical membrane of principal cells (yellow) in the cauda epididymis and in the vesicle-like structures in the apical pole of intermediate zone (interzone) and on the surface of sperm (arrows; B, insets). (C–E) No colocalization was observed in the initial segment (IS), caput (CPT), and corpus (CPS) epididymis. Nuclei were counterstained with DAPI in blue. Bar, 20 µm.