Relative membrane expression of AQP4 phosphorylation mutants in response to hypotonic stimulus
Translocation of phosphomimetic and phospho-blocking mutants of AQP4-GFP in HEK293 cells, measured by confocal microscopy and subsequent image analysis, is shown. Cells were imaged before and after reduction of the extracellular osmolality to 85 mosm/kg of H2O. Each RME value is an average over three independent experiments, with each experiment analyzing at least 3 cells/micrograph and 3 line profiles/cell. Constitutive surface expression was measured by cell surface biotinylation and normalized to wild-type expression. p < 0.05 was considered statistically significant (*). Abbreviation: NA, not applicable.