Functional studies of twelve mutant V2 vasopressin receptors related to nephrogenic diabetes insipidus

Abstract

X-linked nephrogenic diabetes insipidus (NDI) is a rare disease with defective renal and extrarenal arginine vasopressin V2 receptor responses due to mutations in the AVPR2 gene in Xq28. To study the cause of loss of function of mutant V2 receptors, we expressed 12 mutations (N55H, L59P, L83Q, V88M, 497CC-->GG, deltaR202, I209F, 700delC, 908insT, A294P, P322H, P322S) in COS-7 cells. Eleven of these, including P322H, were characterized by a complete loss of function, but the mutation P322S demonstrated a mild clinical and in vitro phenotype. This was characterized by a late diagnosis without any growth or developmental delay and a significant increase in urine osmolality after intravenous 1-deamino[D-Arg8]AVP administration. In vitro, the P322S mutant was able to partially activate the Gs/adenylyl cyclase system in contrast to the other V2R mutants including P322H, which were completely inactive in this regard. This showed not only that Pro 322 is important for proper V2R coupling, but also that the degree of impairment is strongly dependent on the identity of the substituting amino acid. Three-dimensional modeling of the P322H and P322S mutant receptors suggested that the complete loss of function of the P322H receptor could be due, in part, to hydrogen bond formation between the His 322 side chain and the carboxyl group of Asp 85, which does not occur in the P322S receptor.

Structure of the vasopressin hormone-V2 receptor-β-arrestin1 ternary complex

“…S2 ). Indeed, the Ki for AVP was 3.17 ± 0.97 nM (n=3), and the Kact for AVP-induced cAMP production and arrestin recruitment were 0.22 ± 0.09 nM (n=3) and 2.02 ± 0.28 nM (n=4) respectively, in accordance with those determined for a wild-type V2R ( 22, 48, 49 ).…”

Cryo–electron microscopy structure of the antidiuretic hormone arginine-vasopressin V2 receptor signaling complex

“…The cryo-EM version of the V2R bound a fluorescent nonpeptide antagonist and AVP with high affinity [dissociation constant (K d ) and inhibition constant (K i ) = 2.27 ± 0.24 nM (n = 3) and 1.12 ± 0.5 nM (n = 3), respectively], close to the values determined for a wild-type V2R (16). Moreover, the receptor was proven to be functional as it was able to stimulate cAMP accumulation upon AVP binding [K act = 2.05 ± 0.11 nM (n = 4), similar to the wild-type V2R in transfected cells (17)].…”

Association of Calnexin with Wild Type and Mutant AVPR2 that Cause Nephrogenic Diabetes Insipidus

“…Inactivating mutations in the gene coding for the AVPR2 are responsible for an X-linked hereditary disease known as nephrogenic diabetes insipidus (NDI) (). Over 150 different mutations in this gene have been reported to date and of these, over 79 have been expressed in heterologous expression systems ( − ). Surprisingly, over 70% of the expressed mutations lead to receptor proteins that are not expressed on the cell surface.…”