GO:0031857 type 1 parathyroid hormone receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0031857 (type 1 parathyroid hormone receptor binding) is a molecular_function term defined as binding to a type 1 parathyroid hormone receptor (PTH1R).
• PTH1R is a class B1 G protein-coupled receptor that binds parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) to regulate calcium homeostasis and bone metabolism.
• Ligand binding to PTH1R triggers both plasma membrane and endosomal cAMP signaling, which can be biased by ligand and receptor conformation.
• PTH1R signaling is implicated in hepatic fibrosis, osteosarcoma growth, and rare skeletal dysplasias such as Eiken syndrome.
• Caveolin-1 and arrestin proteins modulate PTH1R binding and downstream signaling in bone cells.
• CRISPR-based knockout, point-mutation, knock-in, and overexpression models are essential to dissect PTH1R ligand-binding mechanisms and disease relevance.
Description
GO:0031857, type 1 parathyroid hormone receptor binding, is a molecular_function term that describes the binding of a ligand to the type 1 parathyroid hormone receptor (PTH1R). PTH1R is a class B1 G protein-coupled receptor (GPCR) that mediates the actions of parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP), two peptides critical for calcium homeostasis and bone metabolism. The binding event is the first step in a signaling cascade that can occur at the plasma membrane and in endosomes, leading to diverse cellular responses. Understanding this binding function is fundamental for researchers studying bone biology, calcium regulation, and related diseases. The term is also relevant to cancer biology, as PTH1R signaling has been shown to aggravate hepatic fibrosis and regulate osteosarcoma cell growth. Moreover, mutations in PTH1R can cause rare skeletal disorders such as Eiken syndrome, highlighting the clinical importance of this binding interaction. This article provides a research-grade overview of GO:0031857, covering its definition, mechanism, key genes, disease associations, and experimental methods, with all facts supported by published literature.
type 1 parathyroid hormone receptor binding At A Glance
| GO ID | GO:0031857 |
|---|---|
| GO term | type 1 parathyroid hormone receptor binding |
| Ontology | molecular_function |
| Synonym | type 1 parathyroid hormone receptor ligand |
| Major function | Binding to PTH1R, initiating receptor activation and downstream signaling |
| Receptor | PTH1R (parathyroid hormone type 1 receptor), a class B1 GPCR |
| Ligands | PTH and PTHrP |
| Signaling | Plasma membrane and endosomal cAMP signaling |
| Disease relevance | Hepatic fibrosis, osteosarcoma, Eiken syndrome |
What Is GO:0031857?
According to the QuickGO definition, GO:0031857 (type 1 parathyroid hormone receptor binding) is the binding to a type 1 parathyroid hormone receptor. In other words, it is the molecular function of a ligand (such as PTH or PTHrP) physically interacting with PTH1R. This binding event is the initial step that triggers receptor activation and downstream signaling.
Why Is type 1 parathyroid hormone receptor binding Important in Cell Biology?
GO:0031857 is important because PTH1R binding is the gateway to a signaling axis that controls calcium homeostasis, bone turnover, and multiple disease processes. Dysregulation of PTH1R signaling is linked to hepatic fibrosis, where PTH1R aggravates fibrosis through CREB-like 2 upregulation, and to osteosarcoma growth, where PTH1R interacts with angiotensinogen. Rare mutations in PTH1R cause Eiken syndrome with parathyroid hormone resistance, underscoring the clinical significance of this binding function. Additionally, the binding event is a target for drug development, as biased ligands can differentially activate plasma membrane versus endosomal signaling. Therefore, studying this molecular function is essential for understanding both normal physiology and disease pathogenesis.
• PTH1R binding initiates signaling that regulates calcium and phosphate homeostasis.
• It is the first step in PTH/PTHrP-mediated bone remodeling and skeletal development.
• Endosomal PTH1R signaling prolongs cAMP responses and contributes to sustained biological effects.
• PTH1R signaling aggravates hepatic fibrosis via CREB-like 2, suggesting a role in liver disease.
• PTH1R regulates osteosarcoma cell growth by interacting with angiotensinogen, linking binding to cancer.
• Mutations in PTH1R cause Eiken syndrome, a rare skeletal dysplasia with PTH resistance.
• Caveolin-1 regulates PTHrP actions on PTH1R in bone cells, affecting binding and downstream signaling.
• Arrestin coupling to PTH1R determines desensitization and internalization, impacting drug design.
• Class B1 GPCR activation by intracellular agonists reveals novel binding modes for PTH1R.
• Targeting PTH1R binding is a therapeutic strategy for bone and mineral disorders.
Molecular Mechanism of type 1 parathyroid hormone receptor binding
Ligand Recognition and Binding to PTH1R
In simple terms: PTH or PTHrP docks onto the PTH1R receptor like a key in a lock.
The binding of PTH or PTHrP to PTH1R involves the extracellular domain and transmembrane helices of the receptor. This interaction is highly specific and initiates conformational changes that activate the receptor. The binding affinity and selectivity are influenced by the ligand's N-terminal region and the receptor's extracellular loops.
Receptor Activation and G Protein Coupling
In simple terms: Once the ligand binds, the receptor changes shape and turns on G proteins inside the cell.
Ligand binding to PTH1R induces a conformational shift that allows the receptor to act as a guanine nucleotide exchange factor for Gs and other G proteins. This leads to activation of adenylyl cyclase and production of cAMP. The activation mechanism is characteristic of class B1 GPCRs, as shown by structural studies of intracellular agonist binding.
Plasma Membrane versus Endosomal Signaling
In simple terms: The signal can start at the cell surface or continue after the receptor is internalized into endosomes.
PTH1R signaling is not limited to the plasma membrane; the receptor can be internalized into endosomes where it continues to produce cAMP. This endosomal signaling prolongs the cAMP response and can lead to distinct downstream effects compared to plasma membrane signaling. The balance between these two modes is regulated by ligand properties and receptor trafficking.
Regulation by Caveolin-1 and Arrestins
In simple terms: Other proteins like caveolin-1 and arrestins can tweak how the receptor binds and signals.
Caveolin-1 regulates PTHrP actions on PTH1R in bone cells, affecting ligand binding and downstream signaling. Arrestins couple to PTH1R and mediate desensitization and internalization, with recent structural insights into the core conformation of arrestin coupling. These regulatory proteins fine-tune the duration and intensity of PTH1R signaling.
Downstream Effectors and Transcriptional Responses
In simple terms: The signal travels to the nucleus to change gene expression.
PTH1R activation leads to activation of protein kinase A and exchange protein directly activated by cAMP (EPAC), which in turn regulate transcription factors such as CREB. In hepatic fibrosis, PTH1R signaling upregulates CREB-like 2, contributing to disease progression. In osteosarcoma, PTH1R interacts with angiotensinogen to regulate cell growth.
Key Genes Involved in GO:0031857 type 1 parathyroid hormone receptor binding
The following genes and proteins are directly involved in type 1 parathyroid hormone receptor binding and its downstream signaling.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PTH1R | Receptor for PTH and PTHrP; mediates binding and signaling | Mutations cause Eiken syndrome; target for bone disease |
| PTH | Ligand that binds PTH1R to regulate calcium | Therapeutic use in osteoporosis; studied in bone metabolism |
| PTHLH | Encodes PTHrP, a ligand for PTH1R | Involved in bone development and cancer |
| GNAS | G protein alpha subunit coupled to PTH1R | Mediates cAMP signaling downstream of binding |
| ARRB1 | Arrestin beta 1; regulates PTH1R desensitization | Structural studies of arrestin coupling |
| ARRB2 | Arrestin beta 2; regulates PTH1R internalization | Modulates endosomal signaling |
| CAV1 | Caveolin-1; regulates PTHrP actions on PTH1R | Affects binding and signaling in bone cells |
| CREB1 | Transcription factor activated by PTH1R signaling | Mediates gene expression changes |
| CREBL2 | CREB-like 2; upregulated by PTH1R in hepatic fibrosis | Potential therapeutic target in liver fibrosis |
| AGT | Angiotensinogen; interacts with PTH1R in osteosarcoma | Regulates osteosarcoma cell growth |
| PRKACA | Protein kinase A catalytic subunit; downstream of cAMP | Mediates PTH1R signaling |
| EPAC1 | Exchange protein directly activated by cAMP | Alternative downstream effector |
| EPAC2 | Exchange protein directly activated by cAMP | Alternative downstream effector |
| GNAQ | Gq alpha subunit; may couple to PTH1R | Modulates calcium signaling |
| GNA11 | G11 alpha subunit; may couple to PTH1R | Modulates calcium signaling |
| GRK2 | G protein-coupled receptor kinase 2; phosphorylates PTH1R | Regulates desensitization |
| GRK3 | G protein-coupled receptor kinase 3; phosphorylates PTH1R | Regulates desensitization |
| SLC9A3R1 | NHERF1; scaffolds PTH1R to signaling complexes | Regulates receptor trafficking |
How Is type 1 parathyroid hormone receptor binding Regulated?
The binding of PTH to PTH1R is regulated at multiple levels. Ligand availability is controlled by systemic calcium and phosphate levels, as well as by PTHrP expression in local tissues. Receptor desensitization and internalization are mediated by phosphorylation by G protein-coupled receptor kinases (GRKs) and subsequent arrestin binding. Caveolin-1 modulates PTHrP actions on PTH1R in bone cells, affecting the binding event and downstream signaling. Additionally, endosomal signaling is regulated by the rate of receptor internalization and the activity of endosomal phosphatases. These regulatory mechanisms ensure appropriate physiological responses and are often dysregulated in disease.
type 1 parathyroid hormone receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PTH1R | Eiken syndrome, parathyroid hormone resistance | Knock-in mouse with patient mutation |
| PTH1R | Hepatic fibrosis | Liver-specific knockout or overexpression |
| PTH1R | Osteosarcoma | Xenograft with PTH1R knockout or overexpression |
| CAV1 | Bone metabolism disorders | Caveolin-1 knockout mice |
| ARRB1/ARRB2 | Receptor desensitization defects | Arrestin knockout cell lines |
PTH1R Binding in Hepatic Fibrosis
PTH1R signaling aggravates hepatic fibrosis through upregulating cAMP response element-binding protein-like 2 (CREBL2). This suggests that PTH1R binding and downstream signaling contribute to liver fibrosis progression, and targeting this pathway may offer therapeutic benefits.
PTH1R Binding in Osteosarcoma
Parathyroid hormone type 1 receptor regulates osteosarcoma K7M2 cell growth by interacting with angiotensinogen. This indicates that PTH1R binding and its interaction with angiotensinogen play a role in osteosarcoma proliferation, providing a potential target for cancer therapy.
PTH1R Mutations and Eiken Syndrome
Eiken syndrome with parathyroid hormone resistance is caused by a novel PTH1R mutation. Functional analysis of this mutation reveals impaired binding and signaling, leading to skeletal abnormalities. This highlights the critical role of PTH1R binding in skeletal development.
PTH1R Binding in Bone Metabolism Disorders
PTH and its related peptides are key regulators of bone metabolism. Abnormal PTH1R binding can lead to disorders such as osteoporosis and hyperparathyroidism. Understanding the binding mechanism is essential for developing anabolic therapies for bone.
From type 1 parathyroid hormone receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PTH1R binding mediate hepatic fibrosis? | Liver-specific PTH1R knockout mice |
| How does PTH1R mutation affect ligand binding? | Knock-in mice expressing mutant PTH1R |
| What is the role of PTH1R in osteosarcoma growth? | PTH1R knockout osteosarcoma cell lines |
| How does caveolin-1 regulate PTHrP binding? | CAV1 knockout bone cells |
| What is the structural basis of arrestin coupling? | Point mutations in PTH1R and arrestins |
| Can biased ligands alter endosomal signaling? | Tagged PTH1R knock-in for imaging |
How to Study the type 1 parathyroid hormone receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Radioligand binding | Binding affinity and kinetics | Characterizing PTH1R mutants |
| cAMP ELISA | Intracellular cAMP levels | Assessing Gs activation |
| Luciferase reporter | CRE-driven transcription | Downstream signaling |
| Cryo-EM | 3D structure of receptor-ligand complex | Understanding binding mechanism |
| FRET/BRET | Real-time conformational changes | Endosomal signaling dynamics |
| Immunoprecipitation | Protein-protein interactions | Identifying binding partners |
| RNA-seq | Transcriptional changes | Downstream gene expression |
| CRISPR screening | Genes affecting PTH1R signaling | Identifying novel regulators |
Binding Assays
Radioligand binding assays using 125I-PTH or 125I-PTHrP are standard to measure binding affinity and kinetics to PTH1R. These assays can be performed on cell membranes or whole cells and are used to characterize mutant receptors.
cAMP Signaling Assays
cAMP accumulation assays, such as ELISA or luciferase reporter assays, measure downstream signaling after PTH1R binding. These are used to assess biased agonism and endosomal signaling.
Structural Biology
Cryo-EM and X-ray crystallography have been used to determine structures of PTH1R in complex with ligands and arrestins, revealing the conformational changes upon binding.
Live-Cell Imaging
Fluorescence resonance energy transfer (FRET) and bioluminescence resonance energy transfer (BRET) sensors can monitor PTH1R conformational changes and endosomal cAMP in real time.
How CRISPR Can Be Used to Study GO:0031857 type 1 parathyroid hormone receptor binding
Knockout
CRISPR knockout of PTH1R or its ligands (PTH, PTHLH) can abolish binding and signaling, providing a clean background to study downstream effects. For example, PTH1R knockout in osteosarcoma cells reduces cell growth.
Point Mutation
Introducing point mutations in PTH1R that mimic patient mutations (e.g., Eiken syndrome) allows functional analysis of binding and signaling defects. This approach can reveal critical residues for ligand interaction.
Knock-in
Knock-in of tagged PTH1R (e.g., GFP or HA) enables imaging and biochemical studies of receptor trafficking and binding in live cells. This is useful for studying endosomal signaling.
Overexpression
Overexpression of PTH1R or its ligands can enhance binding signals and is used to study gain-of-function effects. For instance, overexpression of PTH1R in hepatic stellate cells aggravates fibrosis.
How EDITGENE Supports type 1 parathyroid hormone receptor binding Research
Researchers studying type 1 parathyroid hormone receptor binding-related genes often need to determine whether a candidate gene is causally involved in receptor function, signaling, or disease. EDITGENE provides a comprehensive suite of CRISPR services to generate precisely engineered cell and animal models, enabling rigorous functional studies.
Contact EDITGENE today to design your custom CRISPR model for type 1 parathyroid hormone receptor binding research.
Frequently Asked Questions About type 1 parathyroid hormone receptor binding
What is GO:0031857?
GO:0031857 is the Gene Ontology molecular_function term for type 1 parathyroid hormone receptor binding, defined as binding to a type 1 parathyroid hormone receptor (PTH1R).
What genes are involved in type 1 parathyroid hormone receptor binding?
Key genes include PTH1R (the receptor), PTH and PTHLH (ligands), GNAS (G protein), ARRB1/2 (arrestins), and CAV1 (caveolin-1).
What is the function of PTH1R?
PTH1R is a class B1 GPCR that binds PTH and PTHrP to regulate calcium homeostasis, bone metabolism, and other processes.
How does PTH1R signaling work?
Ligand binding to PTH1R activates Gs and cAMP signaling at the plasma membrane and in endosomes, leading to downstream effects.
What diseases are associated with PTH1R mutations?
Mutations in PTH1R can cause Eiken syndrome with parathyroid hormone resistance, and dysregulated signaling is linked to hepatic fibrosis and osteosarcoma.
What is the role of caveolin-1 in PTH1R binding?
Caveolin-1 regulates PTHrP actions on PTH1R in bone cells, affecting binding and downstream signaling.
How do arrestins regulate PTH1R?
Arrestins couple to PTH1R to mediate desensitization and internalization, with structural insights into their binding.
What research methods are used to study PTH1R binding?
Common methods include radioligand binding assays, cAMP assays, cryo-EM, FRET/BRET, and CRISPR-based gene editing.
Can CRISPR be used to study PTH1R function?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect PTH1R binding and signaling.
What is the clinical significance of PTH1R binding?
PTH1R binding is critical for bone health and calcium regulation, and its dysregulation contributes to skeletal disorders, fibrosis, and cancer.
Conclusion
GO:0031857, type 1 parathyroid hormone receptor binding, is a fundamental molecular function that initiates PTH1R signaling, controlling calcium homeostasis, bone metabolism, and diverse disease processes. Understanding the binding mechanism, key genes, and regulatory networks is essential for developing targeted therapies. CRISPR-based models and advanced biochemical assays provide powerful tools to dissect this interaction. EDITGENE offers comprehensive services to support research on PTH1R binding and its role in health and disease.
References
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- 2. Chen T et al.. 2021. Parathyroid hormone and its related peptides in bone metabolism.. Biochem Pharmacol 192:114669 PMID: 34224692
- 3. Peña KA. 2022. Endosomal parathyroid hormone receptor signaling.. Am J Physiol Cell Physiol 323(3):C783-C790 PMID: 35912987
- 4. Heredero-Jiménez S et al.. 2025. Caveolin-1 Regulates Parathyroid Hormone (PTH)-Related Protein (PTHrP) Actions on PTH Receptor Type 1 in Bone Cells.. J Cell Physiol 240(7):e70067 PMID: 40665637
- 5. Zhai X et al.. 2026. Core conformation of arrestin coupling to parathyroid hormone type 1 receptor.. Nat Commun 17(1) PMID: 42034616
- 6. Li S et al.. 2021. Parathyroid hormone type 1 receptor regulates osteosarcoma K7M2 Cell growth by interacting with angiotensinogen.. J Cell Mol Med 25(6):2841-2850 PMID: 33511766
- 7. Calder AD et al.. 2024. Eiken syndrome with parathyroid hormone resistance due to a novel parathyroid hormone receptor type 1 mutation: clinical features and functional analysis.. J Bone Miner Res 39(11):1596-1605 PMID: 39276366
- 8. Kobayashi K et al.. 2023. Class B1 GPCR activation by an intracellular agonist.. Nature 618(7967):1085-1093 PMID: 37286611
