Di?lysine motif?like sequences formed by deleting the C?terminal domain of aquaporin?4 prevent its trafficking to the plasma membrane

Aquaporin-4 is a transmembrane water channel protein, the C-terminal domain of which facing cytosol. In process investigating role aquaporin-4 with regard to intracellular trafficking, we observed that derivative aquaporin-4, in 53 amino acids had been removed (?271-323), was localized compartments, including endoplasmic reticulum, but not expressed on plasma membranes. This determined by immunofluorescence staining and labeling cells monoclonal antibody specifically recognizing extracellular followed confocal microscopy flow cytometry. Deletion additional led its redistribution membrane. suggests effect 53-amino acid deletion subcellular localization could be attributed formation signal at C terminus retained rather than loss required for membrane targeting. Substitution lysine position 268 alanine rescue ?271-323-associated retention cytosol, suggesting sequence mutant served as similar di-lysine motif.