Fig. 2. Two independent motifs determine AQP4 basolateral targeting. (A) Confocal microscopy images of VSV-AQP4 mutants missing the 3 (321 Stop), 21 (303 Stop), 42 (282 Stop) and 52 (272 Stop) C-terminal amino acids, respectively. (B) Confocal microscopy images of AQP4-Δ272–302, Δ272–281 and Δ282–302 mutants bearing internal deletion of 31, 10 and 21 amino acid residues, respectively. An example of quantification of apical versus basolateral expression of the mutants by specific membrane biotinylation and western blotting (see Materials and methods) is shown together with the mean ± SD of at least three experiments.