Agonist binding to peptide hormone receptors

2003 ◽  
Vol 31 (1) ◽  
pp. 35-39 ◽  
Author(s):  
M. Wheatley ◽  
S.R. Hawtin ◽  
V.J. Wesley ◽  
H.C. Howard ◽  
J. Simms ◽  
...  
Keyword(s):  
Hormone Receptors ◽  
Specific Binding ◽  
Peptide Hormone ◽  
Receptor Activation ◽  
Site Directed Mutagenesis ◽  
Receptor Interaction ◽  
Agonist Binding ◽  
Absolute Requirement ◽  
N Terminus ◽  
Peptide Hormone Receptors

A fundamental issue in molecular pharmacology is to define how agonist–receptor interaction differs from that of antagonist–receptor interaction. The V1a vasopressin receptor (V1aR) is a member of a family of related G-protein-coupled receptors (GPCRs) that are activated by vasopressin, oxytocin (OT) and related peptides. A segment of the N-terminus that was required for agonist binding, but not antagonist binding, was identified by characterizing truncated V1aR constructs. Site-directed mutagenesis revealed that a single residue (Arg46) was critical for agonist binding and receptor activation. The N-terminus of the related OT receptor (OTR) could recover agonist binding in a chimaeric OTRN–V1aR construct. Furthermore, Arg34 of the human OTR, which corresponds to Arg46 of the rat V1aR, provided agonist-specific binding epitopes in the OTR, indicating a conserved function of this locus throughout this GPCR subfamily. Mutation of Arg46 revealed that high-affinity agonist binding had an absolute requirement for arginine at this position.

Dual actions of lanthanides on ACTH-inhibited leak K+ channels

2002 ◽  
Vol 282 (6) ◽  
pp. E1255-E1266 ◽  
Author(s):  
John J. Enyeart ◽  
Lin Xu ◽  
Judith A. Enyeart
Keyword(s):  
Binding Sites ◽  
Hormone Receptors ◽  
Peptide Hormone ◽  
Receptor Activation ◽  
Zona Fasciculata ◽  
Ionic Radii ◽  
Whole Cell Patch Clamp ◽  
Acth Receptor ◽  
Dependent Inhibition ◽  
Peptide Hormone Receptors

Bovine adrenal zona fasciculata cells express background K+ channels ( I ACchannels) whose activity is potently inhibited by ACTH. In whole cell patch clamp recordings, it was discovered that the trivalent lanthanides (Ln3+s) lanthanum and ytterbium interact with two binding sites to modulate K+ flow through these channels. Despite large differences in ionic radii, these Ln3+s inhibited I AC channels half-maximally with IC50 values near 50 μM. In addition, these Ln3+s blocked and reversed ACTH-mediated inhibition of I AC K+ channels at similar concentrations. The Ln3+s did not alter inhibition of I AC by angiotensin II or cAMP. Ln3+-induced uncoupling of ACTH receptor activation from I AC inhibition was prevented by raising the external Ca2+ concentration from 2 to 10 mM. The divalent cation Ni2+ (500 μM) also blocked ACTH-dependent inhibition of I AC through a Ca2+-sensitive mechanism. The results are consistent with a model in which Ln3+s produce opposing actions on I AC K+ currents through two separate binding sites. In addition to directly inhibiting I AC, Ln3+s (and Ni2+) bind with high affinity to a Ca2+-selective site associated with the ACTH receptor. By displacing Ca2+ from this site, Ln3+s prevent ACTH from binding and accelerate its dissociation. These results identify Ln3+s as a relatively potent group of noncompetitive ACTH receptor antagonists. Allosteric actions of trivalent and divalent metal cations on hormone binding, mediated through Ca2+-specific sites, may be common to a variety of peptide hormone receptors.

Peptide Hormone “Receptors”: Specific Binding of3H-FSH to Testis

Endocrinology ◽  
1972 ◽  
Vol 90 (1) ◽  
pp. 39-46 ◽  
Author(s):  
ANTHONY R. MEANS ◽  
JUDITH VAITUKAITIS
Keyword(s):  
Hormone Receptors ◽  
Specific Binding ◽  
Peptide Hormone ◽  
Peptide Hormone Receptors

Identification of an extracellular segment of the oxytocin receptor providing agonist-specific binding epitopes

2001 ◽  
Vol 354 (2) ◽  
pp. 465-472 ◽  
Author(s):  
Stuart R. HAWTIN ◽  
Helen C. HOWARD ◽  
Mark WHEATLEY
Keyword(s):  
Specific Binding ◽  
Large Family ◽  
Peptide Hormone ◽  
Distal Portion ◽  
Terminal Segment ◽  
Target Tissue ◽  
Agonist Binding ◽  
Unrelated Sequence ◽  
N Terminus ◽  
Vasopressin V1a Receptor

The effects of the peptide hormone oxytocin are mediated by oxytocin receptors (OTRs) expressed by the target tissue. The OTR is a member of the large family of G-protein-coupled receptors. Defining differences between the interaction of agonists and antagonists with the OTR at the molecular level is of fundamental importance, and is addressed in this study. Using truncated and chimaeric receptor constructs, we establish that a small 12-residue segment in the distal portion of the N-terminus of the human OTR provides important epitopes which are required for agonist binding. In contrast, this segment does not contribute to the binding site for antagonists, whether peptide or non-peptide. It does, however, have a role in agonist-induced OTR signalling. Oxytocin is also an agonist at the vasopressin V1a receptor (V1aR). A chimaeric receptor (V1aRN-OTR) was engineered in which the N-terminus of the OTR was substituted by the corresponding, but unrelated, sequence from the N-terminus of the V1aR. We show that the V1aR N-terminus present in V1aRN-OTR fully restored both agonist binding and intracellular signalling to a dysfunctional truncated OTR construct. The N-terminal segment does not, however, contribute to receptor-selective agonism between the OTR and the V1aR. Our data establish a key role for the distal N-terminus of the OTR in providing agonist-specific binding epitopes.

Peptide Hormone Receptors

1977 ◽  
Vol 39 (1) ◽  
pp. 529-557 ◽  
Author(s):  
K J Catt ◽  
M L Dufau
Keyword(s):  
Hormone Receptors ◽  
Peptide Hormone ◽  
Peptide Hormone Receptors

scholarly journals EXPRESSION OF STEROID AND PEPTIDE HORMONE RECEPTORS, METABOLIC ENZYMES AND EMT-RELATED GENES IN PROSTATE TUMORS IN RELATION TO THE PRESENCE OF THE TMPRSS2/ERG FUSION

2018 ◽  
Vol 40 (2) ◽  
pp. 101-108 ◽  
Author(s):  
G V Gerashchenko ◽  
L V Mevs ◽  
L I Chashchina ◽  
M V Pikul ◽  
O P Gryzodub ◽  
...  
Keyword(s):  
Gene Expression ◽  
Prostate Cancer ◽  
Expression Pattern ◽  
Hormone Receptors ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Peptide Hormone ◽  
Metabolic Enzymes ◽  
Prostate Tumors ◽  
Peptide Hormone Receptors

Aim: To analyze an expression pattern of the steroid and peptide hormone receptors, metabolic enzymes and EMT-related genes in prostate tumors in relation to the presence of the TMPRSS2/ERG fusion; and to examine a putative correlation between gene expression and clinical characteristics, to define the molecular subtypes of prostate cancer. Materials and Methods: The relative gene expression (RE) of 33 transcripts (27 genes) and the presence/absence of the TMPRSS2/ERG fusion were analyzed by a quantitative PCR. 37 prostate cancer tissues (T) paired with conventionally normal prostate tissue (CNT) and 21 samples of prostate adenomas were investigated. RE changes were calculated, using different protocols of statistics. Results: We demonstrated differences in RE of seven genes between tumors and CNT, as was calculated, using the 2−ΔCT model and the Wilcoxon matched paired test. Five genes (ESR1, KRT18, MKI67, MMP9, PCA3) showed altered expression in adenocarcinomas, in which the TMPRSS2/ERG fusion was detected. Two genes (INSR, isoform B and HOTAIR) expressed differently in tumors without fusion. Comparison of the gene expression pattern in adenomas, CNT and adenocarcinomas demonstrated that in adenocarcinomas, bearing the TMPRSS2/ ERG fusion, genes KRT18, PCA3, and SCHLAP1 expressed differently. At the same time, we detected differences in RE of AR (isoform 2), MMP9, PRLR and HOTAIR in adenocarcinomas without the TMPRSS2/ERG fusion. Two genes (ESR1 and SRD5A2) showed differences in RE in both adenocarcinoma groups. Fourteen genes, namely AR (isoforms 1 and 2), CDH1, OCLN, NKX3-1, XIAP, GCR (ins AG), INSR (isoform A), IGF1R, IGF1R tr, PRLR, PRL, VDR and SRD5A2 showed correlation between RE and tumor stage. RE of four genes (CDH2, ESR2, VDR and SRD5A2) correlated with differentiation status of tumors (Gleason score). Using the K-means clustering, we could cluster adenocarcinomas in three groups, according to gene expression profiles. A specific subtype of prostate tumors is characterized by the activated ERG signaling, due to the presence of TMPRSS2/ERG fusion, and also by high levels of the androgen receptor, prolactin, IGF, INSR and PCA3. Conclusions: We have found the specific differences in expression of the steroid and peptide hormone receptors, metabolic enzymes and EMT-related genes, depending on the presence/absence of the TMPRSS2/ERG fusion in prostate adenocarcinomas, CNT and adenomas. We showed three different gene expression profiles of prostate adenocarcinomas. One of them is characteristic for adenocarcinomas with the TMPRSS2/ERG fusion. Further experiments are needed to confirm these data in a larger cohort of patients.

scholarly journals Molecular insights into differentiated ligand recognition of the human parathyroid hormone receptor 2

2021 ◽  
Author(s):  
Xi Wang ◽  
Xi Cheng ◽  
Lihua Zhao ◽  
Yuzhe Wang ◽  
Chenyu Ye ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Hormone Receptor ◽  
Binding Pocket ◽  
Receptor Activation ◽  
Site Directed Mutagenesis ◽  
Hereditary Diseases ◽  
Ligand Specificity ◽  
Parathyroid Hormone Receptor ◽  
N Terminus ◽  
Tuberoinfundibular Peptide

The parathyroid hormone receptor 2 (PTH2R) is a class B1 G protein-coupled receptor (GPCR) involved in regulation of calcium transport, nociception mediation, and wound healing. Naturally occurring mutations in PTH2R were reported to cause hereditary diseases, including syndromic short stature. Here we report the cryo-electron microscopy structure of PTH2R bound to its endogenous ligand, tuberoinfundibular peptide (TIP39), and a heterotrimeric Gs protein at a global resolution of 2.8 Å. The structure reveals that TIP39 adopts a unique loop conformation at N terminus and deeply inserts into the orthosteric ligand-binding pocket in the transmembrane (TM) domain. Molecular dynamics (MD) simulation and site-directed mutagenesis studies uncover the basis of ligand specificity relative to three PTH2R agonists, TIP39, PTH, and PTH-related peptide (PTHrP). We also compare the action of TIP39 with an antagonist lacking six residues from the peptide N terminus, TIP(7-39), which underscores the indispensable role of the N terminus of TIP39 in PTH2R activation. Additionally, we unveil that a disease-associated mutation G258D significantly diminished cAMP accumulation induced by TIP39. Together, these results not only provide structural insights into ligand specificity and receptor activation of class B1 GPCRs, but also offer a foundation to systematically rationalize the available pharmacological data to develop novel therapies for various disorders associated with PTH2R.

scholarly journals Mechanistic basis for the activation of plant membrane receptor kinases by SERK-family coreceptors

2018 ◽  
Vol 115 (13) ◽  
pp. 3488-3493 ◽  
Author(s):  
Ulrich Hohmann ◽  
Julia Santiago ◽  
Joël Nicolet ◽  
Vilde Olsson ◽  
Fabio M. Spiga ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Specific Binding ◽  
Peptide Hormone ◽  
Receptor Activation ◽  
Kinase Domain ◽  
Membrane Receptor ◽  
Activation Mechanism ◽  
In Planta ◽  
Affinity Ligand ◽  
Receptor Kinases

Plant-unique membrane receptor kinases with leucine-rich repeat ectodomains (LRR-RKs) can sense small molecule, peptide, and protein ligands. Many LRR-RKs require SERK-family coreceptor kinases for high-affinity ligand binding and receptor activation. How one coreceptor can contribute to the specific binding of distinct ligands and activation of different LRR-RKs is poorly understood. Here we quantitatively analyze the contribution of SERK3 to ligand binding and activation of the brassinosteroid receptor BRI1 and the peptide hormone receptor HAESA. We show that while the isolated receptors sense their respective ligands with drastically different binding affinities, the SERK3 ectodomain binds the ligand-associated receptors with very similar binding kinetics. We identify residues in the SERK3 N-terminal capping domain, which allow for selective steroid and peptide hormone recognition. In contrast, residues in the SERK3 LRR core form a second, constitutive receptor–coreceptor interface. Genetic analyses of protein chimera between BRI1 and SERK3 define that signaling-competent complexes are formed by receptor–coreceptor heteromerization in planta. A functional BRI1–HAESA chimera suggests that the receptor activation mechanism is conserved among different LRR-RKs, and that their signaling specificity is encoded in the kinase domain of the receptor. Our work pinpoints the relative contributions of receptor, ligand, and coreceptor to the formation and activation of SERK-dependent LRR-RK signaling complexes regulating plant growth and development.

Sign in / Sign up

Export Citation Format

Share Document