Figure 6.

Domain-specific distribution of the Na⁺, K⁺-ATPase isoforms in ARPE-19 cells. Immunofluorescence assays of ARPE-19 cells cultured for 4 weeks with ITS. (A–E) Fluorescence images of immunostaining with isoform-specific antibodies against the α and β subunits of Na⁺, K⁺-ATPase; co-staining with anti-ezrin as an apical marker (A,C,D) or counterstaining with propidium iodide for the detection of nuclei (B,E). β₃ (A) and α₁ (D) subunit expression was detected mainly in the lateral domain. The distribution pattern of the β₂ and α₂ subunits (B,E) suggests an apical localization. The distribution pattern of the β₁ subunit (C) in both the lateral and apical domains suggests non-polarized expression. Minor co-localization with ezrin at the apical domain is observed. The α₁/β₂ (F), α₂/β₁ (G) and α₁/ α₂ subunits (H) do not co-localize. Scale bar: 10 μm.