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CHARACTERIZATION OF MUTANT V2 RECEPTORS ASSOCIATED WITH PARTIAL CONGENITAL NEPHROGENIC DIABETES INSIPIDUS
Author(s) -
Faerch Mia,
Christensen Jane Hvarregaard,
Corydon Thomas Juhl,
Gregersen Niels,
Johansson JanOve,
Zegher Francis,
Rittig Søren
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.748.3
Subject(s) - receptor , mutant , arginine vasopressin receptor 2 , nephrogenic diabetes insipidus , vasopressin , mutation , endocrinology , biology , medicine , microbiology and biotechnology , extracellular , antidiuretic , chemistry , biochemistry , gene , antagonist
X‐linked recessive congenital nephrogenic diabetes insipidus (CNDI) is a disease causing a defective renal response to the effects of the antidiuretic hormone arginine vasopressin (AVP). Two mutations (Arg104Cys and Ser329Arg) associated with partial CNDI were characterized by expression in human embryotic kidney cells. The Arg104Cys mutation in the first extracellular loop and the Ser329Arg mutation in the intracellular C‐terminal demonstrate that despite differences in localization, they have the same effect on receptor processing. Western blotting showed equal amount of receptor protein in WT and mutants. Confocal laser scanning microscopy established that WT receptors were localized on the cellular surface whereas mutant receptors accumulate in a diffuse pattern in the cells. Ligand binding assay demonstrated that the B max for the Arg104Cys and the Ser329Arg mutant receptors were 10‐fold and 2‐fold lower than the WT. There was no difference in AVP affinity (1/K d ) between WT and Ser329Arg mutant receptors, while affinity for Arg104Cys mutant receptors was improved. cAMP assay revealed that the Arg104Cys mutation located in the first extracellular loop produced a lower amount of cAMP compared to WT, but still 4‐fold higher than the Ser329Arg mutation. The mutation Arg104Cys and Ser329Arg of the AVPR2 gene seems to have completely different effects on receptor functionality despite similar phenotypes.