{"gene":"GUCY1A2","run_date":"2026-04-28T18:06:53","timeline":{"discoveries":[{"year":1991,"finding":"The GUCY1A2 gene (encoding the α2 subunit of soluble guanylyl cyclase) was cloned and sequenced. Coexpression experiments in COS cells demonstrated that the α2 subunit can substitute for the α1 subunit (but not the β1 subunit) to form a catalytically active, NO-sensitive heterodimer, establishing the interchangeability of α-subunit isoforms of sGC.","method":"cDNA cloning, sequence analysis, coexpression in COS cells with activity assays","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 — reconstitution of enzymatic activity with defined subunit combinations; foundational cloning paper","pmids":["1683630"],"is_preprint":false},{"year":1995,"finding":"A splice variant of GUCY1A2 (designated α2i) was identified that contains a 31-amino-acid in-frame insert within the catalytic domain, homologous to a region in adenylyl cyclases. When coexpressed with β1, the α2i/β1 heterodimer shows no guanylyl or adenylyl cyclase activity yet retains heterodimerization ability. α2i competes with α2 for β1 dimerization and thereby reduces α2/β1-catalyzed guanylyl cyclase activity, functioning as a dominant negative protein and representing a post-transcriptional regulatory mechanism.","method":"Identification by molecular cloning, coexpression in Sf9 and COS-7 cells, copurification, activity assays, competitive coexpression experiments","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — reconstitution of activity with multiple subunit combinations, mutagenesis-equivalent variant characterization, copurification","pmids":["7673142"],"is_preprint":false},{"year":1998,"finding":"The α2β1 isoform of soluble guanylyl cyclase (containing GUCY1A2/α2 subunit) was demonstrated for the first time to exist naturally at the protein level in human placenta, shown by co-precipitation of α2 with β1. The purified α2β1 heterodimer contains a prosthetic haem group with identical spectral characteristics to α1β1, exhibits indistinguishable kinetic properties and NO sensitivity, and responds similarly to ODQ inhibition and YC-1 activation (including CO sensitization).","method":"Co-precipitation from human placenta, expression and purification from Sf9 cells, UV-vis spectral analysis, kinetic assays, concentration-response measurements with NO/CO/YC-1/ODQ","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 — purified protein, multiple orthogonal biochemical methods, in vitro reconstitution","pmids":["9742221"],"is_preprint":false},{"year":1999,"finding":"The tissue distribution of human GUCY1A2 (α2 subunit of sGC) mRNA was characterized, revealing a more restricted expression pattern compared to α1 and β1 subunits, with high expression specifically in brain, placenta, spleen, and uterus, and the existence of multiple α2 transcripts.","method":"mRNA tissue distribution analysis (Northern blot/RT-PCR across human tissues)","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 2 — direct mRNA expression profiling across tissues; single lab, single method","pmids":["10512742"],"is_preprint":false},{"year":2001,"finding":"The α2β1 isoform (containing GUCY1A2/α2) interacts with the scaffold protein PSD-95 in rat brain, mediated by the α2 C-terminal peptide binding to the third PDZ domain of PSD-95. This interaction recruits the otherwise 'soluble' α2β1 heterodimer to synaptic membranes (membrane fraction of synaptosomes), while α1β1 remains cytosolic, establishing distinct subcellular compartmentalization of the two sGC isoforms and suggesting α2β1 as the NO sensor coupled to PSD-95-associated neuronal NOS.","method":"Coprecipitation from rat brain, recombinant PDZ domain interaction assays, subcellular fractionation of synaptosomes","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — reciprocal coprecipitation from native tissue plus functional localization consequence; multiple methods, mechanistically defined","pmids":["11572861"],"is_preprint":false},{"year":2001,"finding":"The GUCY1A2 (α2) subunit protein was localized in human placenta by immunohistochemistry using novel subunit-specific antibodies, found in syncytiotrophoblast, villous and umbilical blood vessels, and strongly in extravillous (intermediate) trophoblast—sites known for NO and CO production. The alternatively spliced α2i variant was confirmed absent from placenta by RNase protection assay.","method":"Western blot with novel α2-specific antibodies, immunohistochemistry, RNase protection assay","journal":"The Journal of clinical endocrinology and metabolism","confidence":"Medium","confidence_rationale":"Tier 2 — direct protein localization with validated specific antibodies; single lab, multiple methods","pmids":["11158065"],"is_preprint":false},{"year":2007,"finding":"The E3 ubiquitin ligase CHIP ubiquitinates soluble guanylyl cyclase (sGC, which includes the GUCY1A2/α2 subunit) and mediates its proteasomal degradation. CHIP associates with sGC, HSP90, and HSP70 in a chaperone complex; both the tetratricopeptide repeat domain (for chaperone interaction) and U-box domain (for E3 ligase activity) of CHIP are required. In vitro ubiquitination assays with purified proteins confirmed direct CHIP-mediated sGC ubiquitination, and geldanamycin (HSP90 inhibitor) potentiated this ubiquitination and degradation.","method":"Transient overexpression in COS-7 cells, proteasome inhibitor (MG-132) rescue, domain-mutant CHIP constructs, immunoprecipitation, in vitro ubiquitination assay with purified proteins, adenoviral infection of rat aortic smooth muscle cells, rat aortic ring relaxation assay","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"High","confidence_rationale":"Tier 1 — in vitro ubiquitination with purified proteins plus multiple cell-based and tissue-level validations; single lab but multiple orthogonal methods","pmids":["17873020"],"is_preprint":false},{"year":2014,"finding":"Large-scale PDZ domain interaction screening (ProP-PD) identified the C-terminus of GUCY1A2 (guanylate cyclase soluble subunit α-2) as a binding motif for the PDZ domains of Scribble. This interaction was confirmed by colocalization and coimmunoprecipitation of full-length Scribble with GUCY1A2, with PDZ domain affinities in the 1–40 μM range.","method":"Proteomic peptide-phage display (ProP-PD), coimmunoprecipitation, colocalization experiments, recombinant PDZ domain affinity measurements","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"Medium","confidence_rationale":"Tier 2 — phage display discovery confirmed by reciprocal CoIP and colocalization; single study","pmids":["24550280"],"is_preprint":false},{"year":2014,"finding":"X-ray crystallography and native mass spectrometry of human sGC isolated catalytic domains (including the α2 catalytic domain) demonstrated that heterodimerization is necessary but not sufficient for full catalytic activity. Key interfacial residues in an 'interfacial flap' and a hydrogen bond network are required to align the catalytic subunits in a productive conformation; loss of regulatory domains markedly reduces activity even when heterodimers form, indicating that additional domain interactions tune sGC activity by modulating catalytic subunit orientation.","method":"X-ray crystallography, in vitro activity measurements, native mass spectrometry","journal":"Biochemistry","confidence":"High","confidence_rationale":"Tier 1 — crystal structure plus in vitro activity assays plus native MS; multiple orthogonal methods, structural validation","pmids":["24669844"],"is_preprint":false},{"year":2024,"finding":"A de novo heterozygous gain-of-function variant in GUCY1A2, p.(E486D), was identified in a patient with precocious peripheral puberty (resembling autonomous ovarian puberty) and severe intellectual disability. In vitro activity assays of the α2(E486D)/β1 enzyme showed increased nitric oxide affinity (gain-of-function), unchanged response to CO, and decreased thermostability compared to wild-type. Heme content, susceptibility to oxidation, and subcellular localization upon overexpression were unchanged, indicating the activating effect is specific to NO-binding affinity and consequent cGMP elevation.","method":"Exome sequencing, concentration-response measurements in HEK293T cytosolic fractions (wild-type vs. variant), UV-vis absorbance spectroscopy of purified enzymes, confocal laser scanning microscopy of fluorescent protein-tagged constructs","journal":"European journal of endocrinology","confidence":"High","confidence_rationale":"Tier 1 — purified enzyme biochemistry plus cellular assays with multiple orthogonal methods; direct variant characterization","pmids":["38578777"],"is_preprint":false}],"current_model":"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes obligatorily with the β1 subunit to form the catalytically active, NO-sensitive α2β1 isoform; the α2 C-terminal PDZ-binding motif recruits this isoform to synaptic membranes via PSD-95 (and also interacts with Scribble), positioning it near neuronal NOS; a dominant-negative splice variant (α2i) competes for β1 and suppresses activity; sGC protein stability is regulated by the CHIP E3 ligase through HSP90/HSP70-dependent ubiquitination and proteasomal degradation; interfacial residues in the catalytic domain are required for productive subunit alignment and full activity beyond heterodimerization alone; and gain-of-function mutations (e.g., p.E486D) increase NO affinity, elevate cGMP, and cause a syndrome of autonomous ovarian puberty with intellectual disability."},"narrative":{"teleology":[{"year":1991,"claim":"Cloning of GUCY1A2 established that an alternative α subunit can substitute for α1 to form a catalytically active, NO-responsive sGC heterodimer with β1, resolving whether sGC subunit composition is flexible.","evidence":"cDNA cloning and coexpression activity assays in COS cells","pmids":["1683630"],"confidence":"High","gaps":["No information on native protein expression or tissue-specific function","Relative contribution of α2β1 versus α1β1 in vivo unknown"]},{"year":1995,"claim":"Discovery of a catalytically dead splice variant (α2i) that retains β1 heterodimerization and acts as a dominant negative revealed a post-transcriptional mechanism for tuning sGC output.","evidence":"Molecular cloning, coexpression in Sf9 and COS-7 cells, copurification, and competitive coexpression activity assays","pmids":["7673142"],"confidence":"High","gaps":["In vivo expression levels and tissue distribution of α2i not determined","Physiological contexts where dominant-negative regulation is operative remain undefined"]},{"year":1998,"claim":"Purification of native α2β1 from human placenta proved this isoform exists as a functional heme-containing enzyme in vivo, with spectral and kinetic properties identical to α1β1.","evidence":"Co-precipitation from human placenta, Sf9-expressed protein purification, UV-vis spectroscopy, kinetic assays with NO/CO/YC-1/ODQ","pmids":["9742221"],"confidence":"High","gaps":["Whether α2β1 has any unique regulatory properties in native tissue not addressed","Relative abundance of α2β1 versus α1β1 in placenta not quantified"]},{"year":2001,"claim":"Identification of the α2–PSD-95 interaction via the α2 C-terminal PDZ-binding motif explained how α2β1, but not α1β1, is recruited to synaptic membrane fractions, establishing isoform-specific subcellular compartmentalization near neuronal NOS.","evidence":"Coprecipitation from rat brain, recombinant PDZ domain binding assays, synaptosome subcellular fractionation","pmids":["11572861"],"confidence":"High","gaps":["Functional consequence of synaptic targeting for cGMP signaling not directly tested","Whether other PDZ scaffold partners contribute to α2β1 localization in neurons unknown"]},{"year":2007,"claim":"Demonstration that CHIP ubiquitinates sGC (including the α2-containing form) in an HSP90/HSP70-dependent manner and targets it for proteasomal degradation revealed a chaperone-coupled quality-control pathway governing sGC protein stability.","evidence":"In vitro ubiquitination with purified proteins, domain-mutant CHIP constructs, MG-132 rescue, geldanamycin treatment in COS-7 and rat aortic smooth muscle cells, aortic ring relaxation assay","pmids":["17873020"],"confidence":"High","gaps":["Relative susceptibility of α2β1 versus α1β1 to CHIP-mediated degradation not compared","In vivo relevance of this pathway to α2β1 turnover in brain or placenta not examined"]},{"year":2014,"claim":"Structural and biophysical studies showed that heterodimerization of catalytic domains is necessary but insufficient for full activity, with an interfacial flap and hydrogen-bond network required for productive subunit alignment — explaining why regulatory-domain interactions tune catalytic output beyond simple subunit assembly.","evidence":"X-ray crystallography of isolated catalytic domains, native mass spectrometry, in vitro activity measurements","pmids":["24669844"],"confidence":"High","gaps":["Full-length α2β1 structure not resolved","How NO-induced conformational changes propagate through the interfacial flap unknown"]},{"year":2014,"claim":"Identification of Scribble as a second PDZ-scaffold partner for the α2 C-terminus expanded the repertoire of compartmentalization mechanisms and suggested polarity-related signaling roles for α2β1.","evidence":"Proteomic peptide-phage display, coimmunoprecipitation and colocalization of full-length proteins, recombinant PDZ affinity measurements","pmids":["24550280"],"confidence":"Medium","gaps":["Functional consequence of the α2–Scribble interaction on cGMP signaling not tested","Tissue context where this interaction is physiologically relevant not defined","Single study without independent replication"]},{"year":2024,"claim":"A de novo gain-of-function GUCY1A2 variant (p.E486D) causing increased NO affinity and elevated cGMP was linked to precocious peripheral puberty and intellectual disability, providing the first direct human disease association and demonstrating that even modest shifts in NO sensitivity have major physiological consequences.","evidence":"Exome sequencing, concentration-response assays in HEK293T, UV-vis spectroscopy of purified enzyme, confocal microscopy","pmids":["38578777"],"confidence":"High","gaps":["Mechanism by which elevated cGMP causes both ovarian and neurological phenotypes not delineated","Whether loss-of-function variants produce a reciprocal human phenotype unknown"]},{"year":null,"claim":"A full-length structure of the α2β1 heterodimer, the in vivo signaling consequences of synaptic targeting via PSD-95/Scribble, and the tissue-specific physiological roles distinguishing α2β1 from α1β1 remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No full-length α2β1 cryo-EM or crystal structure","Genetic models specifically disrupting α2β1 in brain are lacking","Relative in vivo contribution of α2β1 versus α1β1 to NO–cGMP signaling in each tissue not quantified"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0009975","term_label":"cyclase activity","supporting_discovery_ids":[0,1,2,9]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[0,2,4]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[4]}],"pathway":[{"term_id":"GO:0009975","term_label":"cyclase activity","supporting_discovery_ids":[0,2]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,2,4,9]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[4]}],"complexes":["sGC α2β1 heterodimer"],"partners":["GUCY1B1","DLG4","SCRIB","STUB1","HSP90AA1"],"other_free_text":[]},"mechanistic_narrative":"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes with the β1 subunit to form a heme-containing, NO-sensitive cyclase (α2β1) with kinetic properties and pharmacological responses indistinguishable from the canonical α1β1 isoform [PMID:9742221, PMID:1683630]. A C-terminal PDZ-binding motif unique to α2 recruits the α2β1 heterodimer to synaptic membranes via PSD-95 and also mediates interaction with the scaffold protein Scribble, establishing a compartmentalized NO–cGMP signaling module distinct from cytosolic α1β1 [PMID:11572861, PMID:24550280]. Activity of the α2β1 complex is regulated post-transcriptionally by a dominant-negative splice variant (α2i) that competes for β1 binding without catalytic output, and post-translationally by CHIP E3 ligase-mediated, HSP90/HSP70-dependent ubiquitination and proteasomal degradation [PMID:7673142, PMID:17873020]. A de novo gain-of-function missense variant (p.E486D) that increases NO affinity causes a syndrome of autonomous ovarian puberty with intellectual disability, directly linking α2β1 hyperactivity to human disease [PMID:38578777]."},"prefetch_data":{"uniprot":{"accession":"P33402","full_name":"Guanylate cyclase soluble subunit alpha-2","aliases":[],"length_aa":732,"mass_kda":81.8,"function":"Has guanylyl cyclase on binding to the beta-1 subunit Isoform 2 acts as a negative regulator of guanylyl cyclase activity as it forms non-functional heterodimers with the beta subunits","subcellular_location":"Cytoplasm","url":"https://www.uniprot.org/uniprotkb/P33402/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GUCY1A2","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/GUCY1A2","total_profiled":1310},"omim":[{"mim_id":"601244","title":"GUANYLATE CYCLASE 1, SOLUBLE, ALPHA-2; GUCY1A2","url":"https://www.omim.org/entry/601244"},{"mim_id":"139397","title":"GUANYLATE CYCLASE, SOLUBLE, BETA-1; GUCY1B1","url":"https://www.omim.org/entry/139397"},{"mim_id":"139396","title":"GUANYLATE CYCLASE, SOLUBLE, ALPHA-1; GUCY1A1","url":"https://www.omim.org/entry/139396"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"placenta","ntpm":16.8}],"url":"https://www.proteinatlas.org/search/GUCY1A2"},"hgnc":{"alias_symbol":["GC-SA2"],"prev_symbol":["GUC1A2"]},"alphafold":{"accession":"P33402","domains":[{"cath_id":"3.90.1520.10","chopping":"88-278_285-296","consensus_level":"medium","plddt":80.0861,"start":88,"end":296},{"cath_id":"3.30.450.260","chopping":"320-395_402-447","consensus_level":"medium","plddt":87.8593,"start":320,"end":447},{"cath_id":"3.30.70.1230","chopping":"512-700","consensus_level":"high","plddt":91.9472,"start":512,"end":700}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P33402","model_url":"https://alphafold.ebi.ac.uk/files/AF-P33402-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P33402-F1-predicted_aligned_error_v6.png","plddt_mean":76.06},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GUCY1A2","jax_strain_url":"https://www.jax.org/strain/search?query=GUCY1A2"},"sequence":{"accession":"P33402","fasta_url":"https://rest.uniprot.org/uniprotkb/P33402.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P33402/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P33402"}},"corpus_meta":[{"pmid":"35277538","id":"PMC_35277538","title":"Computational identification of host genomic biomarkers highlighting their functions, pathways and regulators that influence SARS-CoV-2 infections and drug repurposing.","date":"2022","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/35277538","citation_count":32,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"27300296","id":"PMC_27300296","title":"Genome-Wide Association Study between Single Nucleotide Polymorphisms and Flight Speed in Nellore Cattle.","date":"2016","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/27300296","citation_count":29,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38714721","id":"PMC_38714721","title":"Genetic polymorphisms associated with adverse pregnancy outcomes in nulliparas.","date":"2024","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/38714721","citation_count":17,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"28767591","id":"PMC_28767591","title":"Identification of key genes associated with rheumatoid arthritis with bioinformatics approach.","date":"2017","source":"Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28767591","citation_count":14,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38503760","id":"PMC_38503760","title":"Identification of key genes for atherosclerosis in different arterial beds.","date":"2024","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/38503760","citation_count":9,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38001896","id":"PMC_38001896","title":"Role of Pericytes in Cardiomyopathy-Associated Myocardial Infarction Revealed by Multiple Single-Cell Sequencing Analysis.","date":"2023","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/38001896","citation_count":6,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36712057","id":"PMC_36712057","title":"Integrative Multiomics to Dissect the Lung Transcriptional Landscape of Pulmonary Arterial Hypertension.","date":"2023","source":"bioRxiv : the preprint server for biology","url":"https://pubmed.ncbi.nlm.nih.gov/36712057","citation_count":6,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36506088","id":"PMC_36506088","title":"Reduced LYNX1 expression in transcriptome of human iPSC-derived neural progenitors modeling fragile X syndrome.","date":"2022","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/36506088","citation_count":5,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"37277119","id":"PMC_37277119","title":"circ-Gucy1a2 Protects Mice from Cerebral Ischemia-Reperfusion Injury by Attenuating Neuronal Apoptosis and Mitochondrial Membrane Potential Loss.","date":"2023","source":"Journal of investigative surgery : the official journal of the Academy of Surgical Research","url":"https://pubmed.ncbi.nlm.nih.gov/37277119","citation_count":3,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"40596054","id":"PMC_40596054","title":"CXCL8 is essential for cervical cancer cell acquired radioresistance and acts as a promising therapeutic target in cervical cancer.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/40596054","citation_count":3,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38947400","id":"PMC_38947400","title":"Acting mechanism and clinical significance of hsa_circ_0005927 in the invasion and metastasis of gastric cancer.","date":"2024","source":"Journal of Cancer","url":"https://pubmed.ncbi.nlm.nih.gov/38947400","citation_count":3,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"39901736","id":"PMC_39901736","title":"Integrated Transcriptomic and Metabolomic Analysis of Rat PASMCs Reveals the Underlying Mechanism for Pulmonary Arterial Hypertension.","date":"2025","source":"American journal of hypertension","url":"https://pubmed.ncbi.nlm.nih.gov/39901736","citation_count":2,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"36504560","id":"PMC_36504560","title":"Identification of Diagnostic Markers in Infantile Hemangiomas.","date":"2022","source":"Journal of oncology","url":"https://pubmed.ncbi.nlm.nih.gov/36504560","citation_count":2,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"38578777","id":"PMC_38578777","title":"Heterozygous gain of function variant in GUCY1A2 may cause autonomous ovarian hyperfunction.","date":"2024","source":"European journal of endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/38578777","citation_count":1,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"40187516","id":"PMC_40187516","title":"Shared and unique genes and pathways between neuropathic and inflammatory pain assays.","date":"2025","source":"Brain research","url":"https://pubmed.ncbi.nlm.nih.gov/40187516","citation_count":1,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"39473384","id":"PMC_39473384","title":"Soluble Guanylate Cyclase Dysfunction and Nitric Oxide Pathway in Chronic Rhinosinusitis With Nasal Polyps: Predictive Markers for Postoperative Recurrence.","date":"2024","source":"American journal of rhinology & allergy","url":"https://pubmed.ncbi.nlm.nih.gov/39473384","citation_count":1,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"41511324","id":"PMC_41511324","title":"Multi-Omics Mechanism of Chronic Gout Arthritis and Discovery of the Thyroid Hormone-AMPK-Taurine Metabolic Axis.","date":"2025","source":"Cells","url":"https://pubmed.ncbi.nlm.nih.gov/41511324","citation_count":1,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"40551439","id":"PMC_40551439","title":"Genomic Adaptation of Marine Medaka (Oryzias melastigma) Under Artificial Life-History Selection.","date":"2025","source":"Molecular ecology","url":"https://pubmed.ncbi.nlm.nih.gov/40551439","citation_count":0,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"12477932","id":"PMC_12477932","title":"Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.","date":"2002","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/12477932","citation_count":1479,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"28514442","id":"PMC_28514442","title":"Architecture of the human interactome defines protein communities and disease networks.","date":"2017","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/28514442","citation_count":1085,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"32296183","id":"PMC_32296183","title":"A reference map of the human binary protein interactome.","date":"2020","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/32296183","citation_count":849,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"14702039","id":"PMC_14702039","title":"Complete sequencing and characterization of 21,243 full-length human cDNAs.","date":"2003","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/14702039","citation_count":754,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"33961781","id":"PMC_33961781","title":"Dual proteome-scale networks reveal cell-specific remodeling of the human interactome.","date":"2021","source":"Cell","url":"https://pubmed.ncbi.nlm.nih.gov/33961781","citation_count":705,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"21873635","id":"PMC_21873635","title":"Phylogenetic-based propagation of functional annotations within the Gene Ontology consortium.","date":"2011","source":"Briefings in bioinformatics","url":"https://pubmed.ncbi.nlm.nih.gov/21873635","citation_count":656,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"23251661","id":"PMC_23251661","title":"Novel genetic loci identified for the pathophysiology of childhood obesity in the Hispanic population.","date":"2012","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/23251661","citation_count":312,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"22589738","id":"PMC_22589738","title":"Genome-wide association for abdominal subcutaneous and visceral adipose reveals a novel locus for visceral fat in women.","date":"2012","source":"PLoS genetics","url":"https://pubmed.ncbi.nlm.nih.gov/22589738","citation_count":222,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"9742221","id":"PMC_9742221","title":"Functional properties of a naturally occurring isoform of soluble guanylyl cyclase.","date":"1998","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/9742221","citation_count":177,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11572861","id":"PMC_11572861","title":"Guanylyl cyclase/PSD-95 interaction: targeting of the nitric oxide-sensitive alpha2beta1 guanylyl cyclase to synaptic membranes.","date":"2001","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11572861","citation_count":170,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19240061","id":"PMC_19240061","title":"Coeliac disease-associated risk variants in TNFAIP3 and REL implicate altered NF-kappaB signalling.","date":"2009","source":"Gut","url":"https://pubmed.ncbi.nlm.nih.gov/19240061","citation_count":157,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"1683630","id":"PMC_1683630","title":"Molecular cloning and expression of a new alpha-subunit of soluble guanylyl cyclase. Interchangeability of the alpha-subunits of the enzyme.","date":"1991","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/1683630","citation_count":149,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24550280","id":"PMC_24550280","title":"Large-scale interaction profiling of PDZ domains through proteomic peptide-phage display using human and viral phage peptidomes.","date":"2014","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/24550280","citation_count":114,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20379614","id":"PMC_20379614","title":"Personalized smoking cessation: interactions between nicotine dose, dependence and quit-success genotype score.","date":"2010","source":"Molecular medicine (Cambridge, Mass.)","url":"https://pubmed.ncbi.nlm.nih.gov/20379614","citation_count":108,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"10512742","id":"PMC_10512742","title":"Tissue distribution of the human soluble guanylate cyclases.","date":"1999","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/10512742","citation_count":102,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11752394","id":"PMC_11752394","title":"On the activation of soluble guanylyl cyclase by nitric oxide.","date":"2001","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/11752394","citation_count":92,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24366813","id":"PMC_24366813","title":"Interaction proteome of human Hippo signaling: modular control of the co-activator YAP1.","date":"2013","source":"Molecular systems biology","url":"https://pubmed.ncbi.nlm.nih.gov/24366813","citation_count":84,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15123239","id":"PMC_15123239","title":"An improved method for the synthesis of cellulose membrane-bound peptides with free C termini is useful for PDZ domain binding studies.","date":"2004","source":"Chemistry & biology","url":"https://pubmed.ncbi.nlm.nih.gov/15123239","citation_count":75,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"7673142","id":"PMC_7673142","title":"A variant of the alpha 2 subunit of soluble guanylyl cyclase contains an insert homologous to a region within adenylyl cyclases and functions as a dominant negative protein.","date":"1995","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/7673142","citation_count":64,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15094474","id":"PMC_15094474","title":"Expression of nNOS and soluble guanylate cyclase in schizophrenic brain.","date":"2004","source":"Neuroreport","url":"https://pubmed.ncbi.nlm.nih.gov/15094474","citation_count":62,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19948239","id":"PMC_19948239","title":"Role of soluble guanylyl cyclase-cyclic GMP signaling in tumor cell proliferation.","date":"2009","source":"Nitric oxide : biology and chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19948239","citation_count":54,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"30126976","id":"PMC_30126976","title":"Proteome-wide analysis of phospho-regulated PDZ domain interactions.","date":"2018","source":"Molecular systems biology","url":"https://pubmed.ncbi.nlm.nih.gov/30126976","citation_count":48,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24666322","id":"PMC_24666322","title":"HIV-1 protein Tat produces biphasic changes in NMDA-evoked increases in intracellular Ca2+ concentration via activation of Src kinase and nitric oxide signaling pathways.","date":"2014","source":"Journal of neurochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24666322","citation_count":47,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"35575683","id":"PMC_35575683","title":"In-Depth In Vivo Crosslinking in Minutes by a Compact, Membrane-Permeable, and Alkynyl-Enrichable Crosslinker.","date":"2022","source":"Analytical chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/35575683","citation_count":38,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"24669844","id":"PMC_24669844","title":"Interfacial residues promote an optimal alignment of the catalytic center in human soluble guanylate cyclase: heterodimerization is required but not sufficient for activity.","date":"2014","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24669844","citation_count":37,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"36115835","id":"PMC_36115835","title":"Quantitative fragmentomics allow affinity mapping of interactomes.","date":"2022","source":"Nature communications","url":"https://pubmed.ncbi.nlm.nih.gov/36115835","citation_count":33,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"17873020","id":"PMC_17873020","title":"Chaperone-dependent E3 ligase CHIP ubiquitinates and mediates proteasomal degradation of soluble guanylyl cyclase.","date":"2007","source":"American journal of physiology. Heart and circulatory physiology","url":"https://pubmed.ncbi.nlm.nih.gov/17873020","citation_count":29,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"32393512","id":"PMC_32393512","title":"SUMOylation of DDX39A Alters Binding and Export of Antiviral Transcripts to Control Innate Immunity.","date":"2020","source":"Journal of immunology (Baltimore, Md. : 1950)","url":"https://pubmed.ncbi.nlm.nih.gov/32393512","citation_count":27,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"25390645","id":"PMC_25390645","title":"Genome-wide and gene-based association studies of anxiety disorders in European and African American samples.","date":"2014","source":"PloS one","url":"https://pubmed.ncbi.nlm.nih.gov/25390645","citation_count":25,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"11158065","id":"PMC_11158065","title":"Expression and tissue localization of soluble guanylyl cyclase in the human placenta using novel antibodies directed against the alpha(2) subunit.","date":"2001","source":"The Journal of clinical endocrinology and metabolism","url":"https://pubmed.ncbi.nlm.nih.gov/11158065","citation_count":22,"is_preprint":false,"source_track":"gene2pubmed"}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":12190,"output_tokens":1399,"usd":0.028778},"stage2":{"model":"claude-opus-4-6","input_tokens":4639,"output_tokens":2189,"usd":0.11688},"total_usd":0.362089,"stage1_batch_id":"msgbatch_01DzrsgVgYngY1hvM3DU1yF2","stage2_batch_id":"msgbatch_01KA9b7iRzKFdhoBUT7vCvSe","note":"batch pricing = 50% of standard","round2_stage1":{"model":"claude-sonnet-4-6","input_tokens":26427,"output_tokens":5271,"usd":0.079173},"round2_rules_fired":"R3","round2_stage2":{"model":"claude-opus-4-6","input_tokens":6686,"output_tokens":2323,"usd":0.137258}},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2024,\n      \"finding\": \"A heterozygous de novo gain-of-function variant p.(E486D) in GUCY1A2 increases nitric oxide (NO) affinity of the soluble guanylate cyclase α2/β1 heterodimer, leading to elevated cGMP production. The mutant enzyme showed unchanged response to carbon monoxide, decreased thermostability, and unchanged heme content, oxidation susceptibility, and subcellular localization compared to wild-type, establishing that E486D specifically enhances NO sensitivity.\",\n      \"method\": \"In vitro activity assays (concentration-response measurements) in HEK293 cell cytosolic fractions expressing wild-type vs. variant enzyme; UV-vis absorbance spectroscopy of purified enzymes; confocal laser scanning microscopy of fluorescent protein-tagged constructs\",\n      \"journal\": \"European journal of endocrinology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro enzymatic assay with mutagenesis, multiple orthogonal methods (activity, spectroscopy, imaging) in a single rigorous study\",\n      \"pmids\": [\"38578777\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The gain-of-function GUCY1A2 variant p.(E486D) causing increased cGMP was associated with autonomous ovarian hyperfunction (precocious peripheral puberty), suggesting GUCY1A2-driven cGMP elevation impacts the cAMP pathway in ovarian tissue, phenotypically overlapping with McCune-Albright syndrome.\",\n      \"method\": \"Exome sequencing identifying de novo variant; in vitro functional characterization of variant enzyme; clinical phenotyping\",\n      \"journal\": \"European journal of endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis supported by in vitro functional data, but single case report limits causal certainty\",\n      \"pmids\": [\"38578777\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Regulatory network analysis in PAH lung tissue revealed that BMPR2 regulates GUCY1A2 (the α2 subunit of soluble guanylate cyclase, the main target of FDA-approved riociguat) within a co-expression module associated with PAH severity, placing GUCY1A2 downstream of BMPR2 in a vascular remodeling gene network.\",\n      \"method\": \"RNA-seq co-expression network analysis integrated with lung Bayesian regulatory networks and GWAS data from a large PAH biobank\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 4 — computational/network inference only, no direct experimental validation of BMPR2→GUCY1A2 regulation\",\n      \"pmids\": [\"36712057\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"circ-Gucy1a2 (a circular RNA derived from the Gucy1a2 locus) was downregulated in mouse brain tissue after cerebral ischemia-reperfusion injury; overexpression of circ-Gucy1a2 in primary cortical neurons reduced OGD/R-induced apoptosis, mitochondrial membrane potential loss, and oxidative stress, and increased neuronal proliferation.\",\n      \"method\": \"Lentiviral overexpression in vivo (tMCAO mouse model); plasmid overexpression in primary cortical neurons (OGD/R model); CCK-8, flow cytometry, JC-1 staining, H2DFFDA staining; RT-qPCR\",\n      \"journal\": \"Journal of investigative surgery\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — clean loss/gain-of-function with multiple cellular readouts, but mechanism is attributed to a circular RNA from the locus rather than the protein itself\",\n      \"pmids\": [\"37277119\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"GUCY1A2 protein expression was upregulated in nasal polyp tissue of chronic rhinosinusitis with nasal polyps (CRSwNP) patients compared to healthy controls, as validated by Western blotting and immunohistochemistry, implicating soluble guanylate cyclase dysfunction and the NO signaling pathway in CRSwNP pathology.\",\n      \"method\": \"Western blotting and immunohistochemistry in two independent cohorts; protein chip array; ROC curve analysis\",\n      \"journal\": \"American journal of rhinology & allergy\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — protein-level validation but no functional mechanistic experiment on GUCY1A2 activity or pathway\",\n      \"pmids\": [\"39473384\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which forms an α2/β1 heterodimer that converts GTP to cGMP upon nitric oxide binding; a gain-of-function variant p.(E486D) specifically increases NO affinity of the enzyme, elevating intracellular cGMP and causing autonomous ovarian hyperfunction, while a circular RNA derived from the locus (circ-Gucy1a2) independently protects neurons from ischemia-reperfusion injury by reducing apoptosis and mitochondrial membrane potential loss.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\nI'll systematically classify each paper before extracting discoveries.\n\n**CLASSIFICATION:**\n\nRetrieved papers:\n1. PMID:35277538 — GUCY1A2 as hub gene in COVID-19 bioinformatics. Expression/computational only. EXCLUDE (no mechanistic finding).\n2. PMID:27300296 — GWAS in cattle, GUCY1A2 as candidate gene. EXCLUDE (GWAS association only).\n3. PMID:38714721 — GWAS of pregnancy outcomes. EXCLUDE (GWAS association only).\n4. PMID:28767591 — Bioinformatics RA study. EXCLUDE (computational/expression only).\n5. PMID:38503760 — Bioinformatics atherosclerosis study. EXCLUDE (computational only).\n6. PMID:38001896 — Single-cell data, GUCY1A2 listed as expressed in pericytes. EXCLUDE (expression only).\n7. PMID:36712057 — PAH multiomics; mentions BMPR2 regulates GUCY1A2 (riociguat target) in a regulatory network. EXCLUDE (computational regulatory network inference, no direct experiment on GUCY1A2).\n8. PMID:36506088 — FXS transcriptomics; GUCY1A2 altered expression. EXCLUDE (expression only).\n9. PMID:37277119 — circ-Gucy1a2. EXCLUDE (case B: alt-locus product, circular RNA, not canonical protein).\n10. PMID:40596054 — Radioresistance study; GUCY1A2 listed as differentially expressed. EXCLUDE (expression only).\n11. PMID:38947400 — circRNA/gastric cancer; GUCY1A2 as downstream target gene. EXCLUDE (expression/computational only).\n12. PMID:39901736 — PAH transcriptomics/metabolomics in rat PASMCs; GUCY1A2 listed as speculative target. EXCLUDE (speculative/computational).\n13. PMID:36504560 — IH diagnostic markers; GUCY1A2 as diagnostic gene. EXCLUDE (expression/bioinformatics only).\n14. PMID:38578777 — **KEEP**: Direct functional characterization of GUCY1A2 variant p.(E486D); in vitro activity assays, UV-vis spectra, confocal microscopy. Mechanistic study of GUCY1A2 protein.\n15. PMID:40187516 — Pain model RNA-seq; Gucy1a2 differentially expressed. EXCLUDE (expression only).\n16. PMID:39473384 — CRSwNP; GUCY1A2 protein upregulated by WB/IHC. EXCLUDE (expression/biomarker only, no mechanism).\n17. PMID:41511324 — Gout proteomics; GUCY1A2 listed as dysregulated protein. EXCLUDE (expression only).\n18. PMID:40551439 — Marine medaka GWAS; gucy1a2 associated with body weight. EXCLUDE (GWAS association, possible symbol collision with fish ortholog, no mechanistic data).\n\nGene2pubmed curated papers:\n1. PMID:12477932 — MGC cDNA sequencing. EXCLUDE (no mechanistic finding about GUCY1A2).\n2. PMID:28514442 — BioPlex 2.0 interactome. Potentially includes GUCY1A2 interactions but no specific mechanistic finding about GUCY1A2 described. EXCLUDE.\n3. PMID:32296183 — HuRI interactome. Same issue. EXCLUDE.\n4. PMID:14702039 — FLJ cDNA collection. EXCLUDE.\n5. PMID:33961781 — BioPlex 3.0. EXCLUDE (no specific GUCY1A2 mechanism described).\n6. PMID:21873635 — GO phylogenetic propagation. EXCLUDE.\n7. PMID:23251661 — GWAS childhood obesity. EXCLUDE.\n8. PMID:22589738 — GWAS adipose. EXCLUDE.\n9. PMID:9742221 — **KEEP**: First demonstration of α2β1 sGC isoform at protein level; purification, spectral analysis, kinetic characterization, NO/CO/YC-1 responses. Direct biochemical mechanistic study of GUCY1A2 (α2 subunit).\n10. PMID:11572861 — **KEEP**: Demonstrates α2β1 interaction with PSD-95 via α2 C-terminal PDZ-binding motif; coprecipitation, membrane targeting in synaptosomes. Direct mechanistic study of GUCY1A2.\n11. PMID:19240061 — Coeliac disease GWAS. EXCLUDE.\n12. PMID:1683630 — **KEEP**: Cloning of α2 subunit (GUCY1A2); coexpression experiments showing α2 can replace α1 but not β1; catalytic activity demonstrated.\n13. PMID:24550280 — ProP-PD PDZ screen; confirms interaction between GUCY1A2 C-terminus and Scribble PDZ via coIP/colocalization. **KEEP**.\n14. PMID:20379614 — Smoking cessation GWAS. EXCLUDE.\n15. PMID:10512742 — **KEEP**: Tissue distribution of human sGC isoforms including α2 (GUCY1A2); restricted expression pattern demonstrated by mRNA analysis.\n16. PMID:11752394 — Mechanism of NO activation of sGC (α1β1 primarily discussed). Relevant to sGC family mechanism but primarily α1β1. EXCLUDE (focuses on α1β1, not specifically GUCY1A2/α2).\n17. PMID:24366813 — Hippo signaling interactome. EXCLUDE (no specific GUCY1A2 mechanism).\n18. PMID:15123239 — SPOT synthesis PDZ. EXCLUDE (no specific GUCY1A2 finding).\n19. PMID:7673142 — **KEEP**: Characterization of α2i splice variant (dominant negative); insert homologous to adenylyl cyclases; dominant negative mechanism demonstrated by coexpression.\n20. PMID:15094474 — Expression of nNOS and sGC in schizophrenic brain. EXCLUDE (expression only).\n21. PMID:19948239 — sGC-cGMP in tumor proliferation; mentions sGC subunits differentially expressed. EXCLUDE (primarily expression + pharmacology, no specific GUCY1A2 mechanism).\n22. PMID:30126976 — Phospho-PDZ interactions; may include GUCY1A2. EXCLUDE (no specific GUCY1A2 mechanistic finding described).\n23. PMID:24666322 — HIV Tat/NMDA/sGC pathway. EXCLUDE (sGC mentioned as pathway component, no specific GUCY1A2 mechanism).\n24. PMID:35575683 — CXMS crosslinking. EXCLUDE (no specific GUCY1A2 finding described).\n25. PMID:24669844 — **KEEP**: Structural/biochemical study of sGC catalytic domains; X-ray crystallography + activity measurements + native MS; interfacial residues; heterodimerization required but not sufficient. This covers the catalytic domain shared by α2/GUCY1A2 and is directly relevant (human sGC including α2 catalytic domain).\n26. PMID:36115835 — Quantitative fragmentomics PDZ; may include GUCY1A2. EXCLUDE (no specific mechanistic finding described for GUCY1A2).\n27. PMID:17873020 — **KEEP**: CHIP E3 ligase ubiquitinates sGC and mediates proteasomal degradation; direct biochemical mechanism including in vitro ubiquitination assay with purified proteins.\n28. PMID:32393512 — DDX39A SUMOylation. EXCLUDE (not about GUCY1A2).\n29. PMID:25390645 — GWAS anxiety. EXCLUDE.\n30. PMID:11158065 — **KEEP**: Novel antibodies against α2 subunit; localization in human placenta by IHC/Western blot; absence of α2i splice variant confirmed; expression in syncytiotrophoblast and extravillous trophoblast.\n\nNow for PMID:24669844 — this paper studies human sGC catalytic domains. It references both α subunits in the context of heterodimerization. The abstract mentions \"human isolated catalytic domains\" and discusses the sGC heterodimer mechanism. This is relevant to GUCY1A2 as it describes the shared catalytic mechanism. KEEP.\n\nFor PMID:17873020 — CHIP ubiquitinates sGC. The abstract says \"sGC\" generally. It uses COS-7 cells with heterologous sGC expression and rat aortic smooth muscle cells with endogenous sGC. The specific subunit isn't always specified but sGC is the target. Since sGC is a heterodimer of α and β subunits and GUCY1A2 (α2) is a component, this is relevant. KEEP but note it applies to sGC generally.\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1991,\n      \"finding\": \"The GUCY1A2 gene (encoding the α2 subunit of soluble guanylyl cyclase) was cloned and sequenced. Coexpression experiments in COS cells demonstrated that the α2 subunit can substitute for the α1 subunit (but not the β1 subunit) to form a catalytically active, NO-sensitive heterodimer, establishing the interchangeability of α-subunit isoforms of sGC.\",\n      \"method\": \"cDNA cloning, sequence analysis, coexpression in COS cells with activity assays\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution of enzymatic activity with defined subunit combinations; foundational cloning paper\",\n      \"pmids\": [\"1683630\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"A splice variant of GUCY1A2 (designated α2i) was identified that contains a 31-amino-acid in-frame insert within the catalytic domain, homologous to a region in adenylyl cyclases. When coexpressed with β1, the α2i/β1 heterodimer shows no guanylyl or adenylyl cyclase activity yet retains heterodimerization ability. α2i competes with α2 for β1 dimerization and thereby reduces α2/β1-catalyzed guanylyl cyclase activity, functioning as a dominant negative protein and representing a post-transcriptional regulatory mechanism.\",\n      \"method\": \"Identification by molecular cloning, coexpression in Sf9 and COS-7 cells, copurification, activity assays, competitive coexpression experiments\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution of activity with multiple subunit combinations, mutagenesis-equivalent variant characterization, copurification\",\n      \"pmids\": [\"7673142\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"The α2β1 isoform of soluble guanylyl cyclase (containing GUCY1A2/α2 subunit) was demonstrated for the first time to exist naturally at the protein level in human placenta, shown by co-precipitation of α2 with β1. The purified α2β1 heterodimer contains a prosthetic haem group with identical spectral characteristics to α1β1, exhibits indistinguishable kinetic properties and NO sensitivity, and responds similarly to ODQ inhibition and YC-1 activation (including CO sensitization).\",\n      \"method\": \"Co-precipitation from human placenta, expression and purification from Sf9 cells, UV-vis spectral analysis, kinetic assays, concentration-response measurements with NO/CO/YC-1/ODQ\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — purified protein, multiple orthogonal biochemical methods, in vitro reconstitution\",\n      \"pmids\": [\"9742221\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"The tissue distribution of human GUCY1A2 (α2 subunit of sGC) mRNA was characterized, revealing a more restricted expression pattern compared to α1 and β1 subunits, with high expression specifically in brain, placenta, spleen, and uterus, and the existence of multiple α2 transcripts.\",\n      \"method\": \"mRNA tissue distribution analysis (Northern blot/RT-PCR across human tissues)\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct mRNA expression profiling across tissues; single lab, single method\",\n      \"pmids\": [\"10512742\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The α2β1 isoform (containing GUCY1A2/α2) interacts with the scaffold protein PSD-95 in rat brain, mediated by the α2 C-terminal peptide binding to the third PDZ domain of PSD-95. This interaction recruits the otherwise 'soluble' α2β1 heterodimer to synaptic membranes (membrane fraction of synaptosomes), while α1β1 remains cytosolic, establishing distinct subcellular compartmentalization of the two sGC isoforms and suggesting α2β1 as the NO sensor coupled to PSD-95-associated neuronal NOS.\",\n      \"method\": \"Coprecipitation from rat brain, recombinant PDZ domain interaction assays, subcellular fractionation of synaptosomes\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal coprecipitation from native tissue plus functional localization consequence; multiple methods, mechanistically defined\",\n      \"pmids\": [\"11572861\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"The GUCY1A2 (α2) subunit protein was localized in human placenta by immunohistochemistry using novel subunit-specific antibodies, found in syncytiotrophoblast, villous and umbilical blood vessels, and strongly in extravillous (intermediate) trophoblast—sites known for NO and CO production. The alternatively spliced α2i variant was confirmed absent from placenta by RNase protection assay.\",\n      \"method\": \"Western blot with novel α2-specific antibodies, immunohistochemistry, RNase protection assay\",\n      \"journal\": \"The Journal of clinical endocrinology and metabolism\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct protein localization with validated specific antibodies; single lab, multiple methods\",\n      \"pmids\": [\"11158065\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"The E3 ubiquitin ligase CHIP ubiquitinates soluble guanylyl cyclase (sGC, which includes the GUCY1A2/α2 subunit) and mediates its proteasomal degradation. CHIP associates with sGC, HSP90, and HSP70 in a chaperone complex; both the tetratricopeptide repeat domain (for chaperone interaction) and U-box domain (for E3 ligase activity) of CHIP are required. In vitro ubiquitination assays with purified proteins confirmed direct CHIP-mediated sGC ubiquitination, and geldanamycin (HSP90 inhibitor) potentiated this ubiquitination and degradation.\",\n      \"method\": \"Transient overexpression in COS-7 cells, proteasome inhibitor (MG-132) rescue, domain-mutant CHIP constructs, immunoprecipitation, in vitro ubiquitination assay with purified proteins, adenoviral infection of rat aortic smooth muscle cells, rat aortic ring relaxation assay\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro ubiquitination with purified proteins plus multiple cell-based and tissue-level validations; single lab but multiple orthogonal methods\",\n      \"pmids\": [\"17873020\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Large-scale PDZ domain interaction screening (ProP-PD) identified the C-terminus of GUCY1A2 (guanylate cyclase soluble subunit α-2) as a binding motif for the PDZ domains of Scribble. This interaction was confirmed by colocalization and coimmunoprecipitation of full-length Scribble with GUCY1A2, with PDZ domain affinities in the 1–40 μM range.\",\n      \"method\": \"Proteomic peptide-phage display (ProP-PD), coimmunoprecipitation, colocalization experiments, recombinant PDZ domain affinity measurements\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — phage display discovery confirmed by reciprocal CoIP and colocalization; single study\",\n      \"pmids\": [\"24550280\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"X-ray crystallography and native mass spectrometry of human sGC isolated catalytic domains (including the α2 catalytic domain) demonstrated that heterodimerization is necessary but not sufficient for full catalytic activity. Key interfacial residues in an 'interfacial flap' and a hydrogen bond network are required to align the catalytic subunits in a productive conformation; loss of regulatory domains markedly reduces activity even when heterodimers form, indicating that additional domain interactions tune sGC activity by modulating catalytic subunit orientation.\",\n      \"method\": \"X-ray crystallography, in vitro activity measurements, native mass spectrometry\",\n      \"journal\": \"Biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure plus in vitro activity assays plus native MS; multiple orthogonal methods, structural validation\",\n      \"pmids\": [\"24669844\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"A de novo heterozygous gain-of-function variant in GUCY1A2, p.(E486D), was identified in a patient with precocious peripheral puberty (resembling autonomous ovarian puberty) and severe intellectual disability. In vitro activity assays of the α2(E486D)/β1 enzyme showed increased nitric oxide affinity (gain-of-function), unchanged response to CO, and decreased thermostability compared to wild-type. Heme content, susceptibility to oxidation, and subcellular localization upon overexpression were unchanged, indicating the activating effect is specific to NO-binding affinity and consequent cGMP elevation.\",\n      \"method\": \"Exome sequencing, concentration-response measurements in HEK293T cytosolic fractions (wild-type vs. variant), UV-vis absorbance spectroscopy of purified enzymes, confocal laser scanning microscopy of fluorescent protein-tagged constructs\",\n      \"journal\": \"European journal of endocrinology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — purified enzyme biochemistry plus cellular assays with multiple orthogonal methods; direct variant characterization\",\n      \"pmids\": [\"38578777\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes obligatorily with the β1 subunit to form the catalytically active, NO-sensitive α2β1 isoform; the α2 C-terminal PDZ-binding motif recruits this isoform to synaptic membranes via PSD-95 (and also interacts with Scribble), positioning it near neuronal NOS; a dominant-negative splice variant (α2i) competes for β1 and suppresses activity; sGC protein stability is regulated by the CHIP E3 ligase through HSP90/HSP70-dependent ubiquitination and proteasomal degradation; interfacial residues in the catalytic domain are required for productive subunit alignment and full activity beyond heterodimerization alone; and gain-of-function mutations (e.g., p.E486D) increase NO affinity, elevate cGMP, and cause a syndrome of autonomous ovarian puberty with intellectual disability.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes with the β1 subunit to form a nitric oxide (NO)-activated enzyme that converts GTP to cGMP. A de novo gain-of-function variant p.(E486D) specifically increases the NO affinity of the α2/β1 heterodimer without altering heme content, CO responsiveness, or subcellular localization, resulting in elevated cGMP production and autonomous ovarian hyperfunction presenting as peripheral precocious puberty [PMID:38578777]. A circular RNA derived from the locus (circ-Gucy1a2) protects cortical neurons from ischemia-reperfusion injury by reducing apoptosis, mitochondrial membrane potential loss, and oxidative stress [PMID:37277119].\",\n  \"teleology\": [\n    {\n      \"year\": 2023,\n      \"claim\": \"A circular RNA product of the Gucy1a2 locus was shown to have an independent neuroprotective function, establishing that the locus contributes to cerebral ischemia biology through a non-coding RNA mechanism distinct from sGC catalysis.\",\n      \"evidence\": \"Lentiviral overexpression in a tMCAO mouse model and plasmid overexpression in primary cortical neurons subjected to OGD/R, with apoptosis, mitochondrial potential, and oxidative stress readouts\",\n      \"pmids\": [\"37277119\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The downstream molecular targets and miRNA sponging partners of circ-Gucy1a2 are uncharacterized\",\n        \"Whether circ-Gucy1a2 abundance affects sGC protein expression from the same locus is unknown\",\n        \"Findings are from rodent models; relevance to human stroke is unvalidated\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"The first disease-causing variant in GUCY1A2 was identified: p.(E486D) specifically enhances NO sensitivity of the α2/β1 sGC heterodimer, mechanistically linking increased cGMP output to autonomous ovarian hyperfunction and establishing that the α2 subunit tunes NO-dependent activation.\",\n      \"evidence\": \"In vitro activity assays in HEK293 cytosolic fractions, UV-vis spectroscopy of purified enzymes, confocal imaging of tagged constructs, and exome sequencing of an affected patient\",\n      \"pmids\": [\"38578777\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis for how E486D increases NO affinity is unknown; no crystal or cryo-EM structure of the mutant exists\",\n        \"Only a single patient has been reported, limiting genotype-phenotype generalizability\",\n        \"Whether cGMP elevation directly activates the cAMP pathway in ovarian granulosa cells or acts through an intermediate is not resolved\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The tissue-specific regulation, structural determinants of α2 versus α1 subunit utilization, and the full spectrum of human diseases associated with GUCY1A2 loss- or gain-of-function remain uncharacterized.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No loss-of-function human phenotype has been described\",\n        \"No structural model of the full-length α2/β1 heterodimer exists\",\n        \"Upstream transcriptional regulation of GUCY1A2 (e.g., the computationally inferred BMPR2 link) lacks experimental validation\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0009975\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0162582\", \"supporting_discovery_ids\": []},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GUCY1B1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\nWait, let me fix the pathway entry — I accidentally duplicated with wrong ID. Let me provide the corrected JSON:\n\n```json\n{\n  \"mechanistic_narrative\": \"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes with the β1 subunit to form a nitric oxide (NO)-activated enzyme that converts GTP to cGMP. A de novo gain-of-function variant p.(E486D) specifically increases the NO affinity of the α2/β1 heterodimer without altering heme content, CO responsiveness, or subcellular localization, resulting in elevated cGMP production and autonomous ovarian hyperfunction presenting as peripheral precocious puberty [PMID:38578777]. A circular RNA derived from the locus (circ-Gucy1a2) protects cortical neurons from ischemia-reperfusion injury by reducing apoptosis, mitochondrial membrane potential loss, and oxidative stress [PMID:37277119].\",\n  \"teleology\": [\n    {\n      \"year\": 2023,\n      \"claim\": \"A circular RNA product of the Gucy1a2 locus was shown to have an independent neuroprotective function, establishing that the locus contributes to cerebral ischemia biology through a non-coding RNA mechanism distinct from sGC catalysis.\",\n      \"evidence\": \"Lentiviral overexpression in a tMCAO mouse model and plasmid overexpression in primary cortical neurons subjected to OGD/R, with apoptosis, mitochondrial potential, and oxidative stress readouts\",\n      \"pmids\": [\"37277119\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"The downstream molecular targets and miRNA sponging partners of circ-Gucy1a2 are uncharacterized\",\n        \"Whether circ-Gucy1a2 abundance affects sGC protein expression from the same locus is unknown\",\n        \"Findings are from rodent models; relevance to human stroke is unvalidated\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"The first disease-causing variant in GUCY1A2 was identified: p.(E486D) specifically enhances NO sensitivity of the α2/β1 sGC heterodimer, mechanistically linking increased cGMP output to autonomous ovarian hyperfunction and establishing that the α2 subunit tunes NO-dependent activation.\",\n      \"evidence\": \"In vitro activity assays in HEK293 cytosolic fractions, UV-vis spectroscopy of purified enzymes, confocal imaging of tagged constructs, and exome sequencing of an affected patient\",\n      \"pmids\": [\"38578777\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Structural basis for how E486D increases NO affinity is unknown; no crystal or cryo-EM structure of the mutant exists\",\n        \"Only a single patient has been reported, limiting genotype-phenotype generalizability\",\n        \"Whether cGMP elevation directly activates the cAMP pathway in ovarian granulosa cells or acts through an intermediate is not resolved\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The tissue-specific regulation, structural determinants of α2 versus α1 subunit utilization, and the full spectrum of human diseases associated with GUCY1A2 loss- or gain-of-function remain uncharacterized.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\n        \"No loss-of-function human phenotype has been described\",\n        \"No structural model of the full-length α2/β1 heterodimer exists\",\n        \"Upstream transcriptional regulation of GUCY1A2 (e.g., the computationally inferred BMPR2 link) lacks experimental validation\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0009975\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"GUCY1B1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"GUCY1A2 encodes the α2 subunit of soluble guanylate cyclase (sGC), which heterodimerizes with the β1 subunit to form a heme-containing, NO-sensitive cyclase (α2β1) with kinetic properties and pharmacological responses indistinguishable from the canonical α1β1 isoform [PMID:9742221, PMID:1683630]. A C-terminal PDZ-binding motif unique to α2 recruits the α2β1 heterodimer to synaptic membranes via PSD-95 and also mediates interaction with the scaffold protein Scribble, establishing a compartmentalized NO–cGMP signaling module distinct from cytosolic α1β1 [PMID:11572861, PMID:24550280]. Activity of the α2β1 complex is regulated post-transcriptionally by a dominant-negative splice variant (α2i) that competes for β1 binding without catalytic output, and post-translationally by CHIP E3 ligase-mediated, HSP90/HSP70-dependent ubiquitination and proteasomal degradation [PMID:7673142, PMID:17873020]. A de novo gain-of-function missense variant (p.E486D) that increases NO affinity causes a syndrome of autonomous ovarian puberty with intellectual disability, directly linking α2β1 hyperactivity to human disease [PMID:38578777].\",\n  \"teleology\": [\n    {\n      \"year\": 1991,\n      \"claim\": \"Cloning of GUCY1A2 established that an alternative α subunit can substitute for α1 to form a catalytically active, NO-responsive sGC heterodimer with β1, resolving whether sGC subunit composition is flexible.\",\n      \"evidence\": \"cDNA cloning and coexpression activity assays in COS cells\",\n      \"pmids\": [\"1683630\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No information on native protein expression or tissue-specific function\", \"Relative contribution of α2β1 versus α1β1 in vivo unknown\"]\n    },\n    {\n      \"year\": 1995,\n      \"claim\": \"Discovery of a catalytically dead splice variant (α2i) that retains β1 heterodimerization and acts as a dominant negative revealed a post-transcriptional mechanism for tuning sGC output.\",\n      \"evidence\": \"Molecular cloning, coexpression in Sf9 and COS-7 cells, copurification, and competitive coexpression activity assays\",\n      \"pmids\": [\"7673142\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo expression levels and tissue distribution of α2i not determined\", \"Physiological contexts where dominant-negative regulation is operative remain undefined\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"Purification of native α2β1 from human placenta proved this isoform exists as a functional heme-containing enzyme in vivo, with spectral and kinetic properties identical to α1β1.\",\n      \"evidence\": \"Co-precipitation from human placenta, Sf9-expressed protein purification, UV-vis spectroscopy, kinetic assays with NO/CO/YC-1/ODQ\",\n      \"pmids\": [\"9742221\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether α2β1 has any unique regulatory properties in native tissue not addressed\", \"Relative abundance of α2β1 versus α1β1 in placenta not quantified\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Identification of the α2–PSD-95 interaction via the α2 C-terminal PDZ-binding motif explained how α2β1, but not α1β1, is recruited to synaptic membrane fractions, establishing isoform-specific subcellular compartmentalization near neuronal NOS.\",\n      \"evidence\": \"Coprecipitation from rat brain, recombinant PDZ domain binding assays, synaptosome subcellular fractionation\",\n      \"pmids\": [\"11572861\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional consequence of synaptic targeting for cGMP signaling not directly tested\", \"Whether other PDZ scaffold partners contribute to α2β1 localization in neurons unknown\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Demonstration that CHIP ubiquitinates sGC (including the α2-containing form) in an HSP90/HSP70-dependent manner and targets it for proteasomal degradation revealed a chaperone-coupled quality-control pathway governing sGC protein stability.\",\n      \"evidence\": \"In vitro ubiquitination with purified proteins, domain-mutant CHIP constructs, MG-132 rescue, geldanamycin treatment in COS-7 and rat aortic smooth muscle cells, aortic ring relaxation assay\",\n      \"pmids\": [\"17873020\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative susceptibility of α2β1 versus α1β1 to CHIP-mediated degradation not compared\", \"In vivo relevance of this pathway to α2β1 turnover in brain or placenta not examined\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Structural and biophysical studies showed that heterodimerization of catalytic domains is necessary but insufficient for full activity, with an interfacial flap and hydrogen-bond network required for productive subunit alignment — explaining why regulatory-domain interactions tune catalytic output beyond simple subunit assembly.\",\n      \"evidence\": \"X-ray crystallography of isolated catalytic domains, native mass spectrometry, in vitro activity measurements\",\n      \"pmids\": [\"24669844\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full-length α2β1 structure not resolved\", \"How NO-induced conformational changes propagate through the interfacial flap unknown\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Identification of Scribble as a second PDZ-scaffold partner for the α2 C-terminus expanded the repertoire of compartmentalization mechanisms and suggested polarity-related signaling roles for α2β1.\",\n      \"evidence\": \"Proteomic peptide-phage display, coimmunoprecipitation and colocalization of full-length proteins, recombinant PDZ affinity measurements\",\n      \"pmids\": [\"24550280\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the α2–Scribble interaction on cGMP signaling not tested\", \"Tissue context where this interaction is physiologically relevant not defined\", \"Single study without independent replication\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A de novo gain-of-function GUCY1A2 variant (p.E486D) causing increased NO affinity and elevated cGMP was linked to precocious peripheral puberty and intellectual disability, providing the first direct human disease association and demonstrating that even modest shifts in NO sensitivity have major physiological consequences.\",\n      \"evidence\": \"Exome sequencing, concentration-response assays in HEK293T, UV-vis spectroscopy of purified enzyme, confocal microscopy\",\n      \"pmids\": [\"38578777\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which elevated cGMP causes both ovarian and neurological phenotypes not delineated\", \"Whether loss-of-function variants produce a reciprocal human phenotype unknown\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"A full-length structure of the α2β1 heterodimer, the in vivo signaling consequences of synaptic targeting via PSD-95/Scribble, and the tissue-specific physiological roles distinguishing α2β1 from α1β1 remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No full-length α2β1 cryo-EM or crystal structure\", \"Genetic models specifically disrupting α2β1 in brain are lacking\", \"Relative in vivo contribution of α2β1 versus α1β1 to NO–cGMP signaling in each tissue not quantified\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0009975\", \"supporting_discovery_ids\": [0, 1, 2, 9]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [0, 2, 4]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0009975\", \"supporting_discovery_ids\": [0, 2]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 2, 4, 9]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [\n      \"sGC α2β1 heterodimer\"\n    ],\n    \"partners\": [\n      \"GUCY1B1\",\n      \"DLG4\",\n      \"SCRIB\",\n      \"STUB1\",\n      \"HSP90AA1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}