Nephrogenic diabetes insipidus caused by mutation of Tyr205: A key residue of V2 vasopressin receptor function

Abstract

Mutations in the V2 vasopressin receptor (AVPR2) are the most frequent genetic cause of the inherited nephrogenic diabetes insipidus (NDI). About 50% of all missense mutations found in extracellular loops of AVPR2 introduce additional cysteine residues, e.g. R181C, G185C, and Y205C. To explain the loss of receptor function two mechanistic models were suggested: First, the introduction of an additional extracellular Cys residue disrupts the conserved disulfide bond connecting the first and the second extracellular loop. And second, the mutationally introduced Cys residue forms a second disulfide bond with a free Cys residue within the second exoloop. Herein, we took advantage of a new NDI-causing mutation Y205H which affects a codon frequently found to be mutated to Cys in NDI patients. In contrast to Y205C the two mechanisms described above cannot account for the loss of receptor function of Y205H. In-depth functional characterization of mutant AVPR2 showed that also for Y205C the lack of a Tyr residue at position 205 is responsible for the abolished receptor function rather than the formation of a disastrous second disulfide bond. The concerted experimental and phylogenetic analysis emphasizes that Y205 is a key residue in maintaining the structure of AVPR2 and other members of the vasopressin receptor family.

Sildenafil for the Treatment of Congenital Nephrogenic Diabetes Insipidus

“…The sister was heterozygous for the 12 bp-deletion mutation. This deletion of 4 amino acids (Arg-247 to Gly-250) has been previously described and it was suggested that it does not cause effects on receptor function [25] . Having 1 X chromosomal allele mutated in a female, it usually causes symptom of mild NDI.…”

“…Rapid correction of hypernatremia may also predispose these patients toward seizures and cerebral edema [14][15][16] . Severe dehydration and hypernatremia in congenital NDI are avoided by offering free access to water, while urine output can partially be reduced by a combination of treatments including low-salt and low-protein diet, hydrochlorothiazide (HCTZ)-amiloride, and non-steroidal anti-inflammatory drugs [17,18] .…”

Functional characterization of novel loss-of-function mutations in the vasopressin type 2 receptor gene causing nephrogenic diabetes insipidus

“…cAMP content of cell extracts was determined by a non-radioactive cAMP accumulation assay based on the ALPHAScreenä technology according to the manufacturer's protocol (Perkin Elmer LAS, Rodgau-Jügesheim, Germany) [26]. Stimulation with various AVP concentrations ([Arg8]vasopressin acetate salt, Sigma-Aldrich, Seelze, Germany) was performed 48 h after transfection for 1 h at 37°C.…”

Structural and functional evolution of the P2Y12-like receptor group

“…On the basis of available sequence data for validated P2Y receptors, key residues were extracted to define P2Y 12 -like and P2Y 1 -like receptor groups [ 11 , 38 , 39 ]. In recent studies, we have shown for several GPCR that a significant number of orthologs is required for identification of functional motifs and key residues [ 33 , 40 – 42 ]. By mining public databases and by amplifying and sequencing P2Y 12 -like orthologs we have acquired large sets of sequences of P2Y 12 (74 orthologs), P2Y 13 (31 orthologs), P2Y 14 (38 orthologs), GPR87 (51 orthologs), GPR171 (41 orthologs), GPR82 (34 orthologs), and GPR34 (133 orthologs) to determine structural conservation of the members and to identify amino acid sequence motifs and key residues that are unique for the P2Y 12 -like receptor group and the individual members (Fig.…”