Drosophila Zip1 (dZip1) and dZip2 are localized to the plasma membrane. (A-C) Specific localization of dZip1 on the apical side in the larval midgut constriction. dZip1 immunofluorescence staining is red, and nuclear DAPI staining is blue. (A) Specific distribution of dZip1 immunofluorescence (red) in the larval midgut constriction. Arrows denote the midgut constriction. Scale bars = 50 μm. (B) dZip1 (red) is located on the apical membrane of cells in the midgut constriction. Arrowheads and arrows indicate the basal and the apical membranes, respectively. Scale bars = 10 μm. (C) A surface view of the midgut constriction clearly shows the plasma membrane localization of dZip1 (red). Scale bars = 10 μm. (D) Membrane localization of dZip2 expressed in Caco-2 cells. To facilitate visualization, enhanced green fluorescent protein (eGFP)-tagged dZip2 (green) was used. Scale bars = 10 μm. (E) Immunofluorescence (red) against hemagglutinin (HA) reveals apical distribution of dZip2-HA in the midgut cells. DAPI (blue) shows the nucleus. Arrowheads and arrows indicate the basal and the apical membranes, respectively. Scale bars = 10 μm. Flies used are NP3084/UAS-dZip2-HA.