title: Pharmacological lineage analysis revealed the binding affinity of broad-spectrum substance P antagonists to receptors for gonadotropin-releasing peptide.
abstract: A group of synthetic substance P (SP) antagonists, such as [Arg(6),D-Trp(7,9),N(Me)Phe(8)]-substance P(6-11) and [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]-substance P, bind to a range of distinct G-protein-coupled receptor (GPCR) family members, including V1a vasopressin receptors, and they competitively inhibit agonist binding. This extended accessibility enabled us to identify a GPCR subset with a partially conserved binding site structure. By combining pharmacological data and amino acid sequence homology matrices, a pharmacological lineage of GPCRs that are sensitive to these two SP antagonists was constructed. We found that sensitivity to the SP antagonists was not limited to the Gq-protein-coupled V1a and V1b receptors; Gs-coupled V2 receptors and oxytocin receptors, which couple with both Gq and Gi, also demonstrated sensitivity. Unexpectedly, a dendrogram based on the amino acid sequences of 222 known GPCRs showed that a group of receptors sensitive to the SP antagonists are located in close proximity to vasopressin/oxytocin receptors. Gonadotropin-releasing peptide receptors, located near the vasopressin receptors in the dendrogram, were also sensitive to the SP analogs, whereas α1B adrenergic receptors, located more distantly from the vasopressin receptors, were not sensitive. Our finding suggests that pharmacological lineage analysis is useful in selecting subsets of candidate receptors that contain a conserved binding site for a ligand with broad-spectrum binding abilities. The knowledge that the binding site of the two broad-spectrum SP analogs partially overlaps with that of distinct peptide agonists is valuable for understanding the specificity/broadness of peptide ligands.
authors.affiliation: Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Kazune
authors.initials: K
authors.lastname: Arai
authors.affiliation: Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Aki
authors.initials: A
authors.lastname: Kashiwazaki
authors.affiliation: Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Fujiwara
authors.affiliation: Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0498, Japan.
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Tsuchiya
authors.affiliation: Department of Functional Genomics, Graduate School of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo 670-8524, Japan.
authors.forename: Nobuya
authors.initials: N
authors.lastname: Sakai
authors.affiliation: Department of Functional Genomics, Graduate School of Pharmaceutical Sciences, Himeji Dokkyo University, Hyogo 670-8524, Japan.
authors.forename: Katsushi
authors.initials: K
authors.lastname: Shibata
authors.affiliation: Division of Molecular Pharmacology, Department of Pharmacology, Jichi Medical University, Tochigi 329-0498, Japan. Electronic address: t_koshi@jichi.ac.jp.
authors.forename: Taka-aki
authors.initials: TA
authors.lastname: Koshimizu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism; D010455:Peptides / Q000378:metabolism; D018045:Receptors, Oxytocin / Q000737:chemistry / Q000378:metabolism*; D017483:Receptors, Vasopressin / Q000737:chemistry / Q000378:metabolism*; D017385:Sequence Homology; D013373:Substance P / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors*
chemical_list: D010455:Peptides; D018045:Receptors, Oxytocin; D017483:Receptors, Vasopressin; D013373:Substance P; D007987:Gonadotropin-Releasing Hormone
keywords: Arginine vasopressin (PubChem CID: 644077); Broad-spectrum antagonists; Gonadotropin-releasing hormone (PubChem CID: 36523); Ligand affinity; Pharmacological lineage analysis; Substance P (6-11), Arg(6)-Trp(7,9)-Me-Phe(8)- (PubChem CID: 131091); Substance P antagonist; Substance P, Phe(5)-Trp(7,9)-Leu(11)- (PubChem CID: 25077998); Vasopressin/oxytocin receptors