USH1 and USH2 proteins are located in different compartments of the photoreceptors. (A and B) Flat-mount retina. A single confocal z-section illustrating the immunostainings of cadherin-23 and protocadherin-15 (green) in the calyceal processes surrounding the proximal region of the outer segment. Cone labeling (red) from several confocal stacks was used to delineate the outer segment. (C and D) In longitudinal sections of the adult macaque retina, protocadherin-15 (C), cadherin-23 (C), myosin VIIa (D), sans (D), and harmonin (D), but not Vlgr1 (D), are detected along the calyceal processes. Note the intense protocadherin-15 labeling (green) at the inner–outer segment junction in rod photoreceptors (C, left panel, arrows). (D) Vlgr1 immunostaining is restricted to the periciliary membrane complex region, whereas the labeling for myosin VIIa, sans, and harmonin extend further, spreading along the calyceal processes surrounding the cone opsin-labeled outer segment. (E) Double-staining of protocadherin-15 and Vlgr1 (left panels), or sans and Vlgr1 (right panels), further confirms the location of USH1 and USH2 proteins in different subcellular compartments of the photoreceptor cell. Bars: (A and B, left panels) 10 µm; (A and B, right panel, and C–E) 2 µm.