Subtopic Deep Dive
LGR7 and LGR8 Receptor Signaling
Research Guide
What is LGR7 and LGR8 Receptor Signaling?
LGR7 (RXFP1) and LGR8 (RXFP2) are leucine-rich repeat-containing G-protein-coupled receptors activated by relaxin and INSL3 ligands to mediate cAMP/PKA signaling in reproductive tissues.
RXFP1 and RXFP2 possess unique N-terminal low-density lipoprotein class A modules critical for ligand binding and signaling (Scott et al., 2006, 149 citations). INSL3 via RXFP2 drives testicular descent during gestation (Ivell and Anand-Ivell, 2009, 139 citations). Relaxin via RXFP1 regulates matrix metalloproteinases through pERK-nNOS pathways (Chow et al., 2012, 128 citations). Over 10 key papers characterize splice variants, binding sites, and anti-fibrotic effects.
Why It Matters
RXFP1 agonists reduce fibrosis in pregnancy-related cardiovascular disorders by upregulating matrix metalloproteinases via RXFP1-pERK-nNOS-NO-cGMP pathways (Chow et al., 2012). INSL3-RXFP2 signaling supports testicular descent, with disruptions linked to cryptorchidism (Ivell and Anand-Ivell, 2009). RXFP1 suppression inhibits prostate cancer metastasis, suggesting therapeutic targeting (Feng et al., 2010). Selective single-chain RXFP1 agonists treat fibrosis without side effects (Hossain et al., 2016). Halls et al. (2015) detail pharmacology for agonist/antagonist development in reproductive health.
Key Research Challenges
Ligand Binding Specificity
RXFP1 and RXFP2 exhibit multiple binding sites with distinct A-chain roles, complicating selective agonist design (Halls et al., 2005, 112 citations; Hossain et al., 2008, 92 citations). Chimeric receptor studies reveal homology-dependent interactions (Halls et al., 2005).
Splice Variant Signaling
Novel LGR7/LGR8 splice variants mediate signaling via LDL-A modules, but functional impacts remain unclear (Scott et al., 2006, 149 citations). Variability affects cAMP/PKA pathway efficiency.
Downstream Pathway Complexity
RXFP1 signals via pre-assembled complexes with AKAP79, AC2, and PDE4D3 at sub-picomolar levels (Halls and Cooper, 2010, 76 citations). Integrating iNOS and nNOS effects challenges therapeutic modeling (Chow et al., 2012).
Essential Papers
Characterization of Novel Splice Variants of LGR7 and LGR8 Reveals That Receptor Signaling Is Mediated by Their Unique Low Density Lipoprotein Class A Modules
Daniel J. Scott, Sharon Layfield, Yan Yan et al. · 2006 · Journal of Biological Chemistry · 149 citations
The relaxin and insulin-like peptide 3 receptors, LGR7 and LGR8, respectively, are unique members of the leucine-rich repeat-containing G-protein-coupled receptor (LGR) family, because they possess...
Biology of insulin-like factor 3 in human reproduction
Richard Ivell, Ravinder Anand‐Ivell · 2009 · Human Reproduction Update · 139 citations
BACKGROUND Insulin-like factor 3 (INSL3) is a neohormone that has evolved to address specific mammalian traits, in particular, the first phase of testicular descent towards the scrotum during mid-g...
International Union of Basic and Clinical Pharmacology. XCV. Recent Advances in the Understanding of the Pharmacology and Biological Roles of Relaxin Family Peptide Receptors 1–4, the Receptors for Relaxin Family Peptides
Michelle L. Halls, Ross A. D. Bathgate, Steve W. Sutton et al. · 2015 · Pharmacological Reviews · 133 citations
Relaxin Signals through a RXFP1-pERK-nNOS-NO-cGMP-Dependent Pathway to Up-Regulate Matrix Metalloproteinases: The Additional Involvement of iNOS
Bryna Suet Man Chow, Elaine Guo Yan Chew, Chongxin Zhao et al. · 2012 · PLoS ONE · 128 citations
The hormone, relaxin, inhibits aberrant myofibroblast differentiation and collagen deposition by disrupting the TGF-β1/Smad2 axis, via its cognate receptor, Relaxin Family Peptide Receptor 1 (RXFP1...
Anti‐fibrotic actions of relaxin
Chrishan S. Samuel, Simon G. Royce, Tim D. Hewitson et al. · 2016 · British Journal of Pharmacology · 126 citations
Abstract Fibrosis refers to the hardening or scarring of tissues that usually results from aberrant wound healing in response to organ injury, and its manifestations in various organs have collecti...
Multiple Binding Sites Revealed by Interaction of Relaxin Family Peptides with Native and Chimeric Relaxin Family Peptide Receptors 1 and 2 (LGR7 and LGR8)
Michelle L. Halls, C. Bond, Satoko Sudo et al. · 2005 · Journal of Pharmacology and Experimental Therapeutics · 112 citations
The A-chain of Human Relaxin Family Peptides Has Distinct Roles in the Binding and Activation of the Different Relaxin Family Peptide Receptors
Mohammed Akhter Hossain, K. Johan Rosengren, Linda M. Haugaard‐Kedström et al. · 2008 · Journal of Biological Chemistry · 92 citations
The relaxin peptides are a family of hormones that share a structural fold characterized by two chains, A and B, that are cross-braced by three disulfide bonds. Relaxins signal through two differen...
Reading Guide
Foundational Papers
Start with Scott et al. (2006) for splice variants and LDL-A modules, then Halls et al. (2005) for binding sites, Ivell and Anand-Ivell (2009) for INSL3 roles.
Recent Advances
Halls et al. (2015) for RXFP pharmacology; Samuel et al. (2016) for anti-fibrotic actions; Hossain et al. (2016) for single-chain agonists.
Core Methods
LDL-A module assays (Scott et al., 2006); chimeric receptors (Halls et al., 2005); pERK-nNOS-cGMP pathway tracking (Chow et al., 2012); AKAP complex analysis (Halls and Cooper, 2010).
How PapersFlow Helps You Research LGR7 and LGR8 Receptor Signaling
Discover & Search
Research Agent uses searchPapers and exaSearch to find core papers like Scott et al. (2006) on LGR7/LGR8 splice variants. citationGraph maps connections from Halls et al. (2015) pharmacology review to 133 citing works. findSimilarPapers expands from Ivell and Anand-Ivell (2009) to INSL3 reproduction studies.
Analyze & Verify
Analysis Agent applies readPaperContent to extract binding affinities from Halls et al. (2005). verifyResponse with CoVe and GRADE grading checks cAMP pathway claims against Scott et al. (2006). runPythonAnalysis plots dose-response curves from Chow et al. (2012) MMP data using pandas/matplotlib for statistical verification.
Synthesize & Write
Synthesis Agent detects gaps in RXFP1 agonist selectivity via contradiction flagging across Hossain et al. (2008, 2016). Writing Agent uses latexEditText, latexSyncCitations for Scott et al. (2006), and latexCompile to generate pathway diagrams. exportMermaid visualizes RXFP1-pERK-nNOS cascades.
Use Cases
"Analyze INSL3-RXFP2 dose-response data from Ivell 2009 and plot signaling efficiency."
Research Agent → searchPapers(Ivell 2009) → Analysis Agent → readPaperContent → runPythonAnalysis(pandas curve fitting, matplotlib plots) → researcher gets quantified cAMP efficiency graph with R² stats.
"Draft LaTeX review on RXFP1 anti-fibrotic pathways citing Samuel 2016."
Synthesis Agent → gap detection → Writing Agent → latexEditText(manuscript) → latexSyncCitations(Samuel 2016, Chow 2012) → latexCompile → researcher gets compiled PDF with figures and synced bibliography.
"Find code for RXFP1 molecular dynamics simulations from recent papers."
Research Agent → paperExtractUrls(Halls 2015) → paperFindGithubRepo → githubRepoInspect → researcher gets validated simulation scripts linked to receptor binding models.
Automated Workflows
Deep Research workflow conducts systematic review of 50+ RXFP papers: searchPapers → citationGraph → GRADE grading → structured report on signaling pathways. DeepScan applies 7-step analysis with CoVe checkpoints to verify splice variant claims from Scott et al. (2006). Theorizer generates hypotheses on RXFP1 knockout phenotypes from Ivell (2009) and Feng (2010) data.
Frequently Asked Questions
What defines LGR7 and LGR8 receptor signaling?
LGR7 (RXFP1) binds relaxin via LDL-A modules to activate cAMP/PKA; LGR8 (RXFP2) binds INSL3 for reproductive descent signaling (Scott et al., 2006).
What are key methods in this subtopic?
Chimeric receptor assays reveal binding sites (Halls et al., 2005); ERK phosphorylation tracks downstream pathways (Chow et al., 2012).
What are foundational papers?
Scott et al. (2006, 149 citations) on splice variants; Ivell and Anand-Ivell (2009, 139 citations) on INSL3 biology.
What open problems exist?
Selective agonist design for RXFP1 without off-target effects; full mapping of sub-picomolar complex signaling (Halls and Cooper, 2010).
Research Pregnancy-related medical research with AI
PapersFlow provides specialized AI tools for Medicine researchers. Here are the most relevant for this topic:
Systematic Review
AI-powered evidence synthesis with documented search strategies
AI Literature Review
Automate paper discovery and synthesis across 474M+ papers
Find Disagreement
Discover conflicting findings and counter-evidence
Paper Summarizer
Get structured summaries of any paper in seconds
See how researchers in Health & Medicine use PapersFlow
Field-specific workflows, example queries, and use cases.
Start Researching LGR7 and LGR8 Receptor Signaling with AI
Search 474M+ papers, run AI-powered literature reviews, and write with integrated citations — all in one workspace.
See how PapersFlow works for Medicine researchers