Conformational Change in the Ligand-Binding Pocket via a KISS1R Mutation (P147L) Leads to Isolated Gonadotropin-Releasing Hormone Deficiency

Abstract

Context:Kisspeptin receptor (KISS1R) is expressed in hypothalamic gonadotropin-releasing hormone neurons and responsible for pubertal onset and reproductive functions. KISS1R mutations remain a rare cause of congenital hypogonadotropic hypogonadism (CHH).Objective:The aim of this study was to identify the genetic cause of CHH in a patient and to functionally characterize a KISS1R mutation.Design:The patient was a 47-year-old Japanese man whose parents were first cousins. He lacked secondary sexual characteristics owing to normosmic CHH. Exon segments for the KISS1R gene in this patient were screened for mutations. Functional analyses were performed using HEK293 cells expressing KISS1R mutants. Molecular dynamics simulations were performed to compare the ligand-KISS1R mutant complex with those of wild-type KISS1R variants.Results:A homozygous mutation (c.440C>T, p.P147L) in KISS1R was identified. The P147L mutation did not affect either receptor expression level or subcellular localization in the recombinant expression system. Intracellular calcium measurements and cellular dielectric spectroscopy demonstrated that the P147L mutation impaired receptor function to an extent more severe than that of a previously reported L148S mutation. A receptor-ligand binding assay showed the P147L mutation causes a substantial loss of ligand-binding affinity. Molecular dynamics simulations revealed the P147L mutation decreases the contact surface area of the ligand-receptor complex in an expanded ligand-binding pocket.Conclusion:We identified a loss-of-function mutation in KISS1R associated with CHH. Our results demonstrated that the P147L mutation causes a severe phenotype and functional impairment resulting from the loss of ligand-binding affinity due to an expanded ligand-binding pocket.

Heterocyclic Substitutions Greatly Improve Affinity and Stability of Folic Acid towards FRα. an In Silico Insight

“…This could explain the sudden increase in the RMSD plot of FRα in the FA–FRα system at 65 ns ( Figure 7 a). Expansion in the binding pocket may also be an indication of the loss of ligand interactions where the ligand exited from the pocket [ 71 ], as observed in PTX after 80 ns of the MD simulation. It is also observed that after 65 ns, the volumes of binding sites for FOL03–FRα and FOL08–FRα were smaller than for the FA–FRα system.…”

Congenital hypogonadotropic hypogonadism complicated by neuroblastoma

“…The minor allele frequency of the p.P147L (c.C440T) variant in KISS1R , as reported by the Tohoku Medical Megabank Organization (ToMMo), was 0.0005. Moreover, the P147L- KISS1R mutation reportedly causes an almost complete loss of function due to loss of ligand-binding affinity ( 9 ). Based on the 2015 American College of Medical Genetics and Genomics and the Association of Molecular Pathology (ACMG-AMP) guidelines ( 10 ), the P147L- KISS1R mutation was likely pathogenic.…”