Fig. 3. In polarised MDCKI cells, kAE1 is localised to the basolateral membrane. MDCKI cells stably expressing kAE1 were seeded at high density and allowed to polarise. (A) Cells were incubated with anti-AE1 Bric 170, then a biotin-conjugated anti-mouse antibody and visualised using a FITC-labelled anti-biotin antibody. The upper and lower images show focal planes parallel and perpendicular to the cell monolayer, respectively. (B,C) MDCKI-kAE1 cells were double-stained with anti-AE1-Bric 170, and either a tight junction marker anti-ZO-1 antibody (B) or an anti-Na⁺/K⁺ATPase antibody (C). Merged images show kAE1 located on the lateral side of the ZO-1 (B) and colocalises with the basolateral marker Na⁺/K⁺-ATPase (C). Scale bars, 10 µm. AP, apical; BL, basolateral.