title: Germline prokineticin receptor 2 (PROKR2) variants associated with central hypogonadism cause differental modulation of distinct intracellular pathways.
abstract: BACKGROUND
  Defects of prokineticin pathway affect the neuroendocrine control of reproduction, but their role in the pathogenesis of central hypogonadism remains undefined, and the functional impact of the missense PROKR2 variants has been incompletely characterized.
  
  
  METHODS
  In a series of 246 idiopathic central hypogonadism patients, we found three novel (p.V158I, p.V334M, and p.N15TfsX30) and six already known (p.L173R, p.T260M, p.R268C, p.V274D, p.V331M, and p.H20MfsX23) germline variants in the PROKR2 gene. We evaluated the effects of seven missense alterations on two different prokineticin receptor 2 (PROKR2)-dependent pathways: inositol phosphate-Ca(2+) (Gq coupling) and cAMP (Gs coupling).
  
  
  RESULTS
  PROKR2 variants were found in 16 patients (6.5%). Expression levels of variants p.V158I and p.V331M were moderately reduced, whereas they were markedly impaired in the remaining cases, except p.V334M, which was significantly overexpressed. The variants p.T260M, p.R268C, and p.V331M showed no remarkable changes in cAMP response (EC50) whereas the IP signaling appeared more profoundly affected. In contrast, cAMP accumulation cannot be stimulated through the p.L173R and p.V274D, but IP EC50 was similar to wt inp.L173R and increased by 10-fold in p.V274D. The variant p.V334M led to a 3-fold increase of EC50 for both cAMP and IP.
  
  
  CONCLUSIONS
  Our study shows that single PROKR2 missense allelic variants can either affect both signaling pathways differently or selectively. Thus, the integrity of both PROKR2-dependent cAMP and IP signals should be evaluated for a complete functional testing of novel identified allelic variants.
authors.affiliation: Unità di Medicina Generale ad Indirizzo Endocrino-Metabolico e Laboratorio di Ricerche Endocrino-Metaboliche (D.V.L., F.G., L.P., M.Bo.), Istituto Auxologico Italiano, 20149 Milano, Italy; Institute of Experimental Pediatric Endocrinology (G.K.), Charité-Universitätsmedizin, 10117 Berlin, Germany; Dipartimento di Scienze Cliniche e di Comunità (V.V., P.B.-P., L.P.), Università degli Studi di Milano, 20122 Milano, Italy; Consiglio Nazionale delle Ricerche (M.Bu.), Istituto di Neuroscienze, 20129 Milano, Italy; Dipartimento di Scienze Cardiotoraciche e Respiratorie (A.A.S.), Seconda Università di Napoli, 81100 Napoli, Italy; Clinica Medica, AO "San Gerardo dei Tintori" (A.I.P.), Università Milano-Bicocca, 20126 Monza, Italy; Divisione di Endocrinologia (A.M.), Dipartimento di Medicina Interna, Università del Sacro Cuore, 00168 Roma, Italy; Dipartimento di Pediatria (G.R.), Ospedale San Raffaele, 20132 Milano, Italy; Unità di Endocrinologia e Diabetologia (P.B.-P.), Fondazione Policlinico "Cà Granda," 20122 Milano, Italy; Servizio di Endocrinologia Pediatrica (S.L.), Ospedale Microcitemico, ASL Cagliari, 09121 Cagliari, Italy; Ospedale Regionale di Bolzano, 39100 Bolzano, Italy; Dipartimento di Pediatria (M.M.), G. Gaslini, Università di Genova, 16147 Genova, Italy; and Dipartimento di Fisiopatologia Clinica (C.K.), Unità di Andrologia, Università di Firenze, 50121 Firenze, Italy.
authors.forename: Domenico Vladimiro
authors.initials: DV
authors.lastname: Libri
authors.forename: Gunnar
authors.initials: G
authors.lastname: Kleinau
authors.forename: Valeria
authors.initials: V
authors.lastname: Vezzoli
authors.forename: Marta
authors.initials: M
authors.lastname: Busnelli
authors.forename: Fabiana
authors.initials: F
authors.lastname: Guizzardi
authors.forename: Antonio Agostino
authors.initials: AA
authors.lastname: Sinisi
authors.forename: Angela Ida
authors.initials: AI
authors.lastname: Pincelli
authors.forename: Antonio
authors.initials: A
authors.lastname: Mancini
authors.forename: Gianni
authors.initials: G
authors.lastname: Russo
authors.forename: Paolo
authors.initials: P
authors.lastname: Beck-Peccoz
authors.forename: Sandro
authors.initials: S
authors.lastname: Loche
authors.forename: Claudio
authors.initials: C
authors.lastname: Crivellaro
authors.forename: Mohamad
authors.initials: M
authors.lastname: Maghnie
authors.forename: Csilla
authors.initials: C
authors.lastname: Krausz
authors.forename: Luca
authors.initials: L
authors.lastname: Persani
authors.forename: Marco
authors.initials: M
authors.lastname: Bonomi
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D015331:Cohort Studies; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D056726:Genetic Association Studies; D018095:Germ-Line Mutation; D006801:Humans; D007006:Hypogonadism / Q000453:epidemiology / Q000235:genetics*; D007295:Inositol Phosphates / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D043562:Receptors, G-Protein-Coupled / Q000235:genetics*; D018000:Receptors, Peptide / Q000235:genetics*; D015398:Signal Transduction / Q000235:genetics; D055815:Young Adult
chemical_list: D007295:Inositol Phosphates; C470838:PROKR2 protein, human; D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; D000242:Cyclic AMP