Mutation of the histidin residue of the DRH motif in vasopressin V2 receptor expression and function

Background and the purpose of the study: Vasopressin type 2 receptor (V2R), a G protein coupled receptor (GPCR), plays an important role in the regulation of renal antidiuretic function. The highly conserved DRH motif is essential for G protein signaling of V2R; however its role especially regarding the histidin residue is not fully understood.. Methods: Site directed mutagenesis was performed with replacements of the histidin to isoleucine by using nested polymerase chain reaction. ELISA was performed for receptor expression assay and the adenylyl cyclase activity assay was performed for functional characterization of DRI mutation on V2R signaling.Results and major conclusion: The adenylyl cyclase activity assay in COS-7 cells showed no difference in the amount of cAMP production between the wild type and the mutant V2 receptors. The V2 receptor expression was not changed in the presence of this mutation using ELISA assay. These results suggest that the role of histidin residue is not critical in the V2 receptor function, however further mutagenesis studies are required to define the role of this motif in V2R function.