Fig. 7. The dileucine-like and WE motifs are necessary for intracellular targeting of OA1 in MNT1 cells. (A) Immunofluorescence analysis of MNT1 cells transiently transfected with expression vectors for mycHis-tagged OA1 wild-type (OA1 WT), single mutant (OA1 SY and OA1/WEAA) or double mutant (OA1 SY/WEAA) and immunodecorated with anti-His₆ antibodies. OA1 SY/WEAA was colocalized by confocal microscopy with endogenous Na⁺/K⁺ ATPase, a marker of the plasma membrane. In the merge, areas of colocalization can be observed in yellow/orange. Bar, 10 µm. (B) Quantitative immunofluorescence analysis of the subcellular distribution displayed by full-length OA1 constructs in transiently transfected MNT1 cells. Following immunodecoration with anti-His₆ antibodies, transfected cells were counted and classified as described in Fig. 5A. Results represent the mean ± s.e.m. of 3-10 independent experiments. The total number of cells counted is indicated.