Expression and functional characterization of five v2 vasopressin receptor gene mutations identified in families with x-linked nephrogenic diabetes insipidus

The function of five recently identified V2 vasopressin receptor mutations [Y280C, L292P, R337stop, V277A, and G12E (the latter found in the same kindred with L292P)] found in subjects with Xlinked nephtogenic diabetes insipidus (NDI) was studied in COS7 cells transiently transfected with corresponding plasmids. cAMP response to dDAVP and AVP, saturation binding experiments with [3H]-AVP, immunofluorescence, and indirect ELISA studies were performed to characterize receptor targeting to the cell membrane, hormone binding, and signal transduction. These studies show that Y280C, L292P, and R337stop mutations abolish receptor expression and function, V277A subtly but definitely impairs receptor function, and G12E results in a normally functioning receptor. These results provide insight into residues critical for V2 receptor expression and function and define mutations responsible for causing X-linked NDI in affected subjects.