Histidine7.36(305) in the conserved peptide receptor activation domain of the gonadotropin releasing hormone receptor couples peptide binding and receptor activation. (15th February 2015)

• Record Type: Journal Article
• Authors: Mayevu, Nkateko M.I.; Choe, Han; Abagyan, Ruben; Seong, Jae Young; Millar, Robert P.; Katz, Arieh A.; Flanagan, Colleen A.
• Is Part Of: Molecular and cellular endocrinology. Volume 402(2015)
• Page Start: 95
• Page End: 106
• Publication Date: 2015-02-15
• Subjects: 2-Nal 2-naphthylalanine -- B0 radio-ligand bound in the absence of competing unlabeled ligand -- DMEM Dulbecco's modified Eagle's medium -- FCS fetal calf serum -- GnRH gonadotropin releasing hormone -- GPCR G protein-coupled receptor -- IP inositol phosphate -- EC50 half maximal effective concentration -- Emax maximal response -- IC50 half maximal inhibitory concentration -- pEC50 negative log value of EC50 -- PEI polyethylenimine -- pIC50 negative log value of IC50 -- rNTR1 rat neurotensin receptor type 1 -- TM transmembrane helix; G protein-coupled receptor (GPCR) -- Peptide hormone -- Hormone receptor -- Receptor structure-function -- Peptide interaction -- GnRH; Endocrinology -- Periodicals; Molecular biology -- Periodicals; Cytology -- Periodicals; Endocrinology -- Periodicals; Hormones -- Periodicals; Endocrinologie -- Périodiques; Cytology; Endocrinology; Molecular biology; Periodicals; 573.4
• DOI: 10.1016/j.mce.2015.01.008
• Languages: English
• ISSNs: 0303-7207

Abstract

Highlights: His 7.36(305) is proposed to couple GnRH receptor agonist binding with activation. Trp 3 is important for full agonist potency of the GnRH peptide. His 7.36(305) determines GnRH receptor recognition of Trp 3 of GnRH. Both His 7.36(305) and Trp 3 are required for full GnRH signaling potency. His 7.36(305) may indirectly couple Trp 3 binding to the receptor activation mechanism. Abstract: Transmembrane helix seven residues of G protein-coupled receptors (GPCRs) couple agonist binding to a conserved receptor activation mechanism. Amino-terminal residues of the GnRH peptide determine agonist activity. We investigated GnRH interactions with the His 7.36(305) residue of the GnRH receptor, using functional and computational analysis of modified GnRH receptors and peptides. Non-polar His 7.36(305) substitutions decreased receptor affinity for GnRH four- to forty-fold, whereas GnRH signaling potency was more decreased (~150-fold). Uncharged polar His 7.36(305) substitutions decreased GnRH potency, but not affinity. [2-Nal 3 ]-GnRH retained high affinity at receptors with non-polar His 7.36(305) substitutions, supporting a role for His 7.36(305) in recognizing Trp 3 of GnRH. Compared with GnRH, [2-Nal 3 ]-GnRH potency was lower at the wild type GnRH receptor, but unchanged or higher at mutant receptors. Results suggest that His 7.36(305) of the GnRH receptor forms two distinct interactions that determine binding to Trp 3 and couple agonist binding to the conserved transmembrane domain network that activates GPCRs.