{"gene":"P4HA2","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":2015,"finding":"C-P4H-II (encoded by P4HA2) is an α2β2 tetrameric collagen prolyl 4-hydroxylase that catalyzes formation of 4-hydroxyproline residues required for collagen triple helix formation and thermal stability; C-P4H-II predominates in chondrocytes. P4ha2-/- mice showed no overt phenotype alone, but P4ha1(+/-);P4ha2(-/-) compound mutant mice exhibited chondrodysplasia, kyphosis, reduced 4-hydroxyproline content, decreased collagen II melting temperature, and biomechanically impaired extracellular matrix, demonstrating that C-P4H-I can largely compensate for C-P4H-II loss in endochondral bone development.","method":"Genetic knockout mouse models (P4ha2-/-, P4ha1+/-;P4ha2-/- compound mutants), collagen biochemistry (hydroxyproline quantification, Tm measurement), histology, atomic force microscopy","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 / Strong — multiple orthogonal methods (genetic KO, biochemical collagen assays, mechanical measurements) in one rigorous study with clear phenotypic readouts","pmids":["26001784"],"is_preprint":false},{"year":2006,"finding":"HIF-1 transcriptionally upregulates P4HA2 (and P4HA1) in primary human articular chondrocytes under hypoxia (1% O2); this upregulation is abolished by the HIF-1 inhibitor 2-methoxyestradiol, indicating P4HA2 is a HIF-1 target gene that contributes to increased posttranslational collagen modification under low-oxygen conditions.","method":"Primary human chondrocyte culture under 1% O2, real-time PCR, HIF-1 inhibition with 2-methoxyestradiol, immunohistochemistry on OA cartilage","journal":"The American journal of pathology","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — pharmacological HIF inhibition used to establish pathway; single lab, two methods (qPCR + IHC), but no direct ChIP or promoter assay","pmids":["16877351"],"is_preprint":false},{"year":2007,"finding":"siRNA-mediated silencing of P4HA2 activates HIF-1, which attenuates TNF-α-induced expression of CXC chemokines (KC, LIX), CC chemokine MCP-1, and ICAM-1 in cardiomyocytes in vitro and in postischemic hearts in vivo, reducing neutrophil infiltration and myocardial infarct size by >60%; this places P4HA2 upstream of HIF-1 in cardiac ischemia-reperfusion inflammatory signaling.","method":"siRNA knockdown of P4HA2 in HL-1 cardiomyocytes and murine in vivo I/R model, cytokine/chemokine quantification, infarct size measurement, leukocyte infiltration assay","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo KD with defined phenotypic readouts; single lab, but multiple orthogonal endpoints (molecular + histological + functional)","pmids":["17545479"],"is_preprint":false},{"year":2010,"finding":"Wild-type p53 transcriptionally induces P4HA2 mRNA in glioblastoma cells (demonstrated by p53 overexpression, shRNA knockdown, and chemical induction); however, in glioblastoma this p53-driven P4HA2 mRNA upregulation does not lead to increased P4HA2 protein, increased endostatin production, or antiangiogenic effects on endothelial cells, indicating a silenced downstream signaling pathway specific to this tumor type.","method":"p53 overexpression in TP53-deleted LN-308 cells, shRNA knockdown in LNT-229 cells, camptothecin-induced p53 activation, RT-PCR, western blot, endothelial cell sprouting/viability/transmigration assays","journal":"Neuro-oncology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — three orthogonal approaches to manipulate p53 establish transcriptional regulation of P4HA2; single lab; downstream negative finding rigorously confirmed","pmids":["20504876"],"is_preprint":false},{"year":2018,"finding":"A missense variant c.1147A>G (p.Lys383Glu) in P4HA2 reduces P4HA2 mRNA and protein expression and decreases collagen hydroxylation and deposition in primary mutant fibroblasts compared to healthy cell lines, demonstrating that P4HA2 catalytic activity is required for normal collagen hydroxylation and that loss-of-function causes myopic axial elongation.","method":"Whole-exome sequencing, in vitro studies with primary fibroblast cultures from mutation carriers vs. controls (RT-qPCR, western blot, collagen hydroxylation assay)","journal":"Clinical genetics","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — functional in vitro validation of the variant with multiple molecular readouts; single lab, patient-derived cells","pmids":["29364500"],"is_preprint":false},{"year":2012,"finding":"Overexpression of P4HA2 in the Hs578T breast cancer cell line suppresses cell proliferation and migration, while RNA interference of P4HA2 has the opposite effect, establishing a functional role of P4HA2 in regulating breast cancer cell behavior in vitro.","method":"P4HA2 overexpression and siRNA knockdown in Hs578T cells, proliferation assays, migration assays","journal":"Biochemistry. Biokhimiia","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, single set of cell-based assays, no mechanistic pathway placement beyond the phenotype","pmids":["22813596"],"is_preprint":false},{"year":2023,"finding":"IGF-II induces P4HA2 mRNA and protein expression in primary human lung fibroblasts via the IGF1R/IR hybrid receptor and this induction is regulated downstream in a SOX9-dependent manner, placing P4HA2 in an IGF-II→IGF1R/IR hybrid receptor→SOX9→P4HA2 profibrotic signaling axis.","method":"Primary human lung fibroblast treatment with IGF-II, receptor knockdown/inhibition, SOX9 siRNA knockdown, RT-qPCR, western blot","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2-3 / Moderate — epistasis established by receptor and transcription factor knockdown upstream of P4HA2; single lab, multiple molecular readouts","pmids":["37510994"],"is_preprint":false},{"year":2025,"finding":"P4HA1 and P4HA2 are required for HIF-1α translation and HIF-2α transcription and translation in VHL-deficient clear cell renal cell carcinoma (ccRCC) cells independently of pVHL; this regulation is mediated in part through P4HA1/2-driven collagen production, revealing a pVHL-independent mechanism by which collagen prolyl hydroxylases sustain HIF-α levels.","method":"P4HA1/P4HA2 knockdown/knockout in ccRCC cells, western blot for HIF-1α and HIF-2α protein, collagen production assays, pVHL-deficient cell models","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 2-3 / Weak — preprint, single lab, mechanistic details in abstract are partial; novel pVHL-independent pathway claim not yet peer-reviewed","pmids":[],"is_preprint":true},{"year":2026,"finding":"P4ha2-/- knockout mice show compromised visual acuity, time-dependent disruption of collagen fibril arrangement in sclera and cornea due to decreased collagen hydroxylation (reduced thermal stability), elevated fibronectin, and reduced collagen I in sclera/cornea; P4HA2-knockout HEK293 cells replicate the ECM imbalance, establishing that P4HA2-mediated collagen hydroxylation is required for normal scleral/corneal ECM composition and refractive function.","method":"P4ha2-/- knockout mice and P4HA2-knockout HEK293 cells (CRISPR), biometric visual assessments, electron microscopy of collagen fibrils, collagen hydroxylation quantification, western blot for fibronectin and collagen I","journal":"Human mutation","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — genetic KO in two independent systems (mouse and cell line) with multiple orthogonal biochemical and structural endpoints; single lab","pmids":["41756678"],"is_preprint":false},{"year":2026,"finding":"In vitro activity assays using CRISPR-generated P4ha1-/-;P4ha2-/- cells (with P4HA3 as the only remaining isoform) showed no 4-hydroxyproline formation in type I collagen, demonstrating that P4HA3 does not hydroxylate type I collagen, and that prolyl 4-hydroxylation of type I collagen is mediated exclusively by P4HA1 and P4HA2.","method":"CRISPR/Cas9 knockout cells (P4ha3-/-, P4ha1-/-;P4ha2-/-), C-P4H activity assays, 4-hydroxyproline content measurement, collagen Tm, pepsin-resistance assay, collagen fibril assembly assay","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — direct enzymatic activity assay and multiple collagen biochemistry readouts in genetically defined cell lines; single lab with multiple orthogonal methods","pmids":["41999892"],"is_preprint":false},{"year":2025,"finding":"Quercetin downregulates P4HA2 expression in hepatocellular carcinoma (HCC) cells, and P4HA2 knockdown enhances quercetin-induced apoptosis; the apoptotic effect is mediated through inhibition of the PI3K/Akt/mTOR pathway, placing P4HA2 upstream of this survival signaling axis in HCC cells.","method":"P4HA2 siRNA knockdown in HCC cells, quercetin treatment, PI3K/Akt/mTOR pathway inhibitors (LY294002, Z-VAD-FMK) and activator (740Y-P), cell viability and apoptosis assays","journal":"Cancer reports (Hoboken, N.J.)","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, pharmacological pathway dissection without direct biochemical reconstitution; mechanistic link between P4HA2 and PI3K/Akt is indirect","pmids":["40347062"],"is_preprint":false},{"year":2026,"finding":"BMAL1 knockdown reduces P4HA2 and COL2A1 expression in both macroscopically normal and OA chondrocytes under high-glucose conditions, placing P4HA2 downstream of the circadian clock transcription factor BMAL1 in a glucose-responsive collagen synthesis pathway.","method":"Primary human chondrocyte culture under high glucose, BMAL1 siRNA knockdown, RT-qPCR, western blot, secreted collagen II quantification","journal":"Osteoarthritis and cartilage open","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, siRNA epistasis shows BMAL1 regulates P4HA2 but no direct promoter or binding evidence; single method per finding","pmids":["41630778"],"is_preprint":false}],"current_model":"P4HA2 encodes the catalytic α-subunit of collagen prolyl 4-hydroxylase isoenzyme II (C-P4H-II), an α2β2 tetramer that catalyzes hydroxylation of proline residues in collagen chains to 4-hydroxyproline, which is essential for collagen triple-helix formation, thermal stability, and proper extracellular matrix assembly; P4HA2 is transcriptionally induced by HIF-1 under hypoxia and by p53, regulated downstream of IGF-II/SOX9 and BMAL1 signaling axes, functionally redundant with P4HA1 in most tissues (but not replaceable by P4HA3 for type I collagen), and required in vivo for normal scleral/corneal collagen organization, chondrocyte-mediated endochondral bone development, and—in ccRCC—for pVHL-independent maintenance of HIF-1α and HIF-2α levels through collagen production."},"narrative":{"mechanistic_narrative":"P4HA2 encodes the catalytic α-subunit of collagen prolyl 4-hydroxylase isoenzyme II (C-P4H-II), an α2β2 tetrameric enzyme that converts proline residues in collagen chains to 4-hydroxyproline, a modification required for collagen triple-helix formation and thermal stability [PMID:26001784]. Together with P4HA1, P4HA2 accounts entirely for prolyl 4-hydroxylation of type I collagen, as the remaining isoform P4HA3 cannot hydroxylate type I collagen [PMID:41999892]; C-P4H-I can largely compensate for loss of C-P4H-II in endochondral bone development, but compound loss produces chondrodysplasia, reduced 4-hydroxyproline content, and biomechanically impaired matrix [PMID:26001784]. P4HA2-dependent hydroxylation is required for normal extracellular matrix composition in vivo: loss of P4HA2 disrupts scleral and corneal collagen fibril arrangement, lowers collagen thermal stability, elevates fibronectin, reduces collagen I, and compromises visual acuity [PMID:41756678], and a loss-of-function missense variant that reduces P4HA2 expression and collagen hydroxylation underlies myopic axial elongation [PMID:29364500]. Transcriptionally, P4HA2 is induced by HIF-1 under hypoxia [PMID:16877351] and by wild-type p53 [PMID:20504876], and is regulated downstream of an IGF-II→IGF1R/IR hybrid receptor→SOX9 profibrotic axis in lung fibroblasts [PMID:37510994]. Beyond these collagen-modifying and regulatory roles, the broader signaling context captured here is limited to individual cell-type studies.","teleology":[{"year":2006,"claim":"Established that P4HA2 is an oxygen-responsive gene, linking collagen post-translational modification capacity to hypoxic signaling.","evidence":"Primary human chondrocytes under 1% O2 with qPCR and pharmacological HIF-1 inhibition","pmids":["16877351"],"confidence":"Medium","gaps":["No direct ChIP or promoter-binding evidence for HIF-1 occupancy","Pharmacological inhibitor may have off-target effects","Limited to chondrocytes"]},{"year":2007,"claim":"Placed P4HA2 upstream of HIF-1 in cardiac inflammatory signaling, indicating its loss can feed back into HIF-driven transcription with functional cardioprotective consequences.","evidence":"siRNA knockdown in HL-1 cardiomyocytes and murine ischemia-reperfusion model with chemokine, infarct-size, and leukocyte readouts","pmids":["17545479"],"confidence":"Medium","gaps":["Mechanism by which P4HA2 loss activates HIF-1 not resolved","Single lab","Relationship to collagen hydroxylation activity unclear"]},{"year":2010,"claim":"Showed P4HA2 is a transcriptional target of wild-type p53, while revealing tumor-type-specific uncoupling of mRNA induction from protein output.","evidence":"p53 overexpression, shRNA knockdown, and chemical induction in glioblastoma cells with RT-PCR and western blot","pmids":["20504876"],"confidence":"Medium","gaps":["Cause of the mRNA-to-protein uncoupling not identified","No direct p53 promoter-binding assay","Single tumor context"]},{"year":2012,"claim":"Reported a context-dependent role for P4HA2 in regulating breast cancer cell proliferation and migration.","evidence":"Overexpression and siRNA knockdown in Hs578T cells with proliferation and migration assays","pmids":["22813596"],"confidence":"Low","gaps":["No mechanistic pathway placement beyond phenotype","Single cell line, single lab","Direction of effect not linked to collagen hydroxylation"]},{"year":2015,"claim":"Defined P4HA2's enzymatic identity and its functional redundancy with P4HA1, establishing C-P4H-II as the chondrocyte-predominant collagen prolyl 4-hydroxylase whose loss is largely compensable.","evidence":"P4ha2-/- and P4ha1+/-;P4ha2-/- mouse models with hydroxyproline quantification, collagen Tm, histology and atomic force microscopy","pmids":["26001784"],"confidence":"High","gaps":["Degree of redundancy in non-chondrocyte tissues not fully mapped","Substrate selectivity between isoforms not defined"]},{"year":2018,"claim":"Demonstrated that P4HA2 catalytic activity is required for normal collagen hydroxylation in humans, linking loss-of-function to myopic axial elongation.","evidence":"Whole-exome sequencing plus patient-derived fibroblast assays (RT-qPCR, western blot, collagen hydroxylation)","pmids":["29364500"],"confidence":"Medium","gaps":["Single family/variant","No animal rescue of the specific variant","Mechanism connecting reduced hydroxylation to ocular axial growth not detailed"]},{"year":2023,"claim":"Positioned P4HA2 within an IGF-II→IGF1R/IR hybrid receptor→SOX9 profibrotic axis in lung fibroblasts.","evidence":"Primary human lung fibroblasts with IGF-II treatment, receptor knockdown/inhibition, SOX9 siRNA, RT-qPCR and western blot","pmids":["37510994"],"confidence":"Medium","gaps":["No direct SOX9 promoter-binding evidence at P4HA2","Single lab","In vivo fibrosis relevance not established"]},{"year":2025,"claim":"Proposed a pVHL-independent mechanism whereby P4HA1/2-driven collagen production sustains HIF-1α and HIF-2α levels in VHL-deficient ccRCC.","evidence":"P4HA1/P4HA2 knockdown/knockout in ccRCC cells with HIF-α western blots and collagen production assays (preprint)","pmids":[],"confidence":"Low","gaps":["Preprint, not peer-reviewed","Mechanistic link between collagen production and HIF-α translation/transcription only partial","Single lab"]},{"year":2025,"claim":"Linked P4HA2 to PI3K/Akt/mTOR survival signaling and quercetin-induced apoptosis in hepatocellular carcinoma cells.","evidence":"siRNA knockdown with quercetin treatment and pharmacological pathway modulators in HCC cells; viability and apoptosis assays","pmids":["40347062"],"confidence":"Low","gaps":["Mechanistic link between P4HA2 and PI3K/Akt is indirect","No biochemical reconstitution","Single lab"]},{"year":2026,"claim":"Established that P4HA2-mediated collagen hydroxylation is required for proper scleral/corneal ECM composition and refractive function in vivo.","evidence":"P4ha2-/- mice and CRISPR P4HA2-knockout HEK293 cells with electron microscopy, hydroxylation quantification and western blots","pmids":["41756678"],"confidence":"Medium","gaps":["Mechanism connecting fibronectin elevation/collagen I reduction not fully resolved","Single lab"]},{"year":2026,"claim":"Showed that prolyl 4-hydroxylation of type I collagen is mediated exclusively by P4HA1 and P4HA2, with P4HA3 unable to substitute.","evidence":"CRISPR P4ha3-/- and P4ha1-/-;P4ha2-/- cells with direct C-P4H activity assays, hydroxyproline, collagen Tm, pepsin-resistance and fibril assembly assays","pmids":["41999892"],"confidence":"High","gaps":["Isoform-specific substrate preferences across collagen types not fully mapped","Single lab"]},{"year":2026,"claim":"Placed P4HA2 downstream of the circadian transcription factor BMAL1 in a glucose-responsive collagen synthesis pathway in chondrocytes.","evidence":"BMAL1 siRNA knockdown in primary human chondrocytes under high glucose with RT-qPCR, western blot and collagen II quantification","pmids":["41630778"],"confidence":"Low","gaps":["No direct BMAL1 promoter-binding evidence","Single method per readout","Single lab"]},{"year":null,"claim":"How the multiple upstream transcriptional inputs (HIF-1, p53, SOX9, BMAL1) are integrated to set P4HA2-dependent collagen hydroxylation in specific tissues, and the precise mechanism linking P4HA2/collagen production to HIF-α stabilization, remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No unified model integrating the distinct transcriptional regulators","pVHL-independent HIF-α mechanism unconfirmed in peer review","Tissue-specific isoform redundancy incompletely mapped"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016491","term_label":"oxidoreductase activity","supporting_discovery_ids":[0,9]},{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,4,9]}],"localization":[],"pathway":[{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[0,8]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,9]}],"complexes":["collagen prolyl 4-hydroxylase (C-P4H-II)"],"partners":["P4HA1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"O15460","full_name":"Prolyl 4-hydroxylase subunit alpha-2","aliases":["Procollagen-proline,2-oxoglutarate-4-dioxygenase subunit alpha-2"],"length_aa":535,"mass_kda":60.9,"function":"Catalyzes the post-translational formation of 4-hydroxyproline in -Xaa-Pro-Gly- sequences in collagens and other proteins","subcellular_location":"Endoplasmic reticulum lumen","url":"https://www.uniprot.org/uniprotkb/O15460/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/P4HA2","classification":"Not Classified","n_dependent_lines":3,"n_total_lines":1208,"dependency_fraction":0.0024834437086092716},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[{"gene":"KIF7","stoichiometry":10.0},{"gene":"CPSF6","stoichiometry":0.2},{"gene":"PSPC1","stoichiometry":0.2},{"gene":"SRP9","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/search/P4HA2","total_profiled":1310},"omim":[{"mim_id":"617238","title":"MYOPIA 25, AUTOSOMAL DOMINANT; MYP25","url":"https://www.omim.org/entry/617238"},{"mim_id":"608987","title":"PROCOLLAGEN-PROLINE, 2-OXOGLUTARATE-4-DIOXYGENASE, ALPHA SUBUNIT, ISOFORM 3; P4HA3","url":"https://www.omim.org/entry/608987"},{"mim_id":"606348","title":"INFLAMMATORY BOWEL DISEASE 5; IBD5","url":"https://www.omim.org/entry/606348"},{"mim_id":"600608","title":"PROCOLLAGEN-PROLINE, 2-OXOGLUTARATE-4-DIOXYGENASE, ALPHA SUBUNIT, ISOFORM 2; P4HA2","url":"https://www.omim.org/entry/600608"},{"mim_id":"176710","title":"PROCOLLAGEN-PROLINE, 2-OXOGLUTARATE-4-DIOXYGENASE, ALPHA SUBUNIT, ISOFORM 1; P4HA1","url":"https://www.omim.org/entry/176710"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Enhanced","locations":[{"location":"Endoplasmic reticulum","reliability":"Enhanced"},{"location":"Vesicles","reliability":"Enhanced"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/P4HA2"},"hgnc":{"alias_symbol":["C-P4Halpha(II)","lncRNA-PE"],"prev_symbol":[]},"alphafold":{"accession":"O15460","domains":[{"cath_id":"1.25.40.10","chopping":"127-264","consensus_level":"high","plddt":94.5517,"start":127,"end":264},{"cath_id":"2.60.120.620","chopping":"290-520","consensus_level":"high","plddt":91.8318,"start":290,"end":520},{"cath_id":"1.10.287","chopping":"21-122","consensus_level":"high","plddt":91.7198,"start":21,"end":122}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O15460","model_url":"https://alphafold.ebi.ac.uk/files/AF-O15460-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O15460-F1-predicted_aligned_error_v6.png","plddt_mean":89.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=P4HA2","jax_strain_url":"https://www.jax.org/strain/search?query=P4HA2"},"sequence":{"accession":"O15460","fasta_url":"https://rest.uniprot.org/uniprotkb/O15460.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O15460/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O15460"}},"corpus_meta":[{"pmid":"16877351","id":"PMC_16877351","title":"Regulation of type II collagen synthesis during osteoarthritis by prolyl-4-hydroxylases: possible influence of low oxygen levels.","date":"2006","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/16877351","citation_count":76,"is_preprint":false},{"pmid":"28041642","id":"PMC_28041642","title":"A Genome-wide Association Study Identifies Risk Alleles in Plasminogen and P4HA2 Associated with Giant Cell Arteritis.","date":"2016","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/28041642","citation_count":75,"is_preprint":false},{"pmid":"17545479","id":"PMC_17545479","title":"Activation of hypoxia-inducible factor-1 via prolyl-4 hydoxylase-2 gene silencing attenuates acute inflammatory responses in postischemic myocardium.","date":"2007","source":"American journal of physiology. Heart and circulatory physiology","url":"https://pubmed.ncbi.nlm.nih.gov/17545479","citation_count":64,"is_preprint":false},{"pmid":"17213842","id":"PMC_17213842","title":"Refined genomic localization and ethnic differences observed for the IBD5 association with Crohn's disease.","date":"2007","source":"European journal of human genetics : EJHG","url":"https://pubmed.ncbi.nlm.nih.gov/17213842","citation_count":63,"is_preprint":false},{"pmid":"26001784","id":"PMC_26001784","title":"Severe Extracellular Matrix Abnormalities and Chondrodysplasia in Mice Lacking Collagen Prolyl 4-Hydroxylase Isoenzyme II in Combination with a Reduced Amount of Isoenzyme I.","date":"2015","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26001784","citation_count":48,"is_preprint":false},{"pmid":"29364500","id":"PMC_29364500","title":"Autosomal-dominant myopia associated to a novel P4HA2 missense variant and defective collagen hydroxylation.","date":"2018","source":"Clinical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/29364500","citation_count":24,"is_preprint":false},{"pmid":"20504876","id":"PMC_20504876","title":"Defective p53 antiangiogenic signaling in glioblastoma.","date":"2010","source":"Neuro-oncology","url":"https://pubmed.ncbi.nlm.nih.gov/20504876","citation_count":17,"is_preprint":false},{"pmid":"37510994","id":"PMC_37510994","title":"The Role of SOX9 in IGF-II-Mediated Pulmonary Fibrosis.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37510994","citation_count":12,"is_preprint":false},{"pmid":"30589377","id":"PMC_30589377","title":"Early posterior vitreous detachment is associated with LAMA5 dominant mutation.","date":"2018","source":"Ophthalmic genetics","url":"https://pubmed.ncbi.nlm.nih.gov/30589377","citation_count":11,"is_preprint":false},{"pmid":"28488544","id":"PMC_28488544","title":"A long non-coding RNA lncRNA-PE promotes invasion and epithelial-mesenchymal transition in hepatocellular carcinoma through the miR-200a/b-ZEB1 pathway.","date":"2017","source":"Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine","url":"https://pubmed.ncbi.nlm.nih.gov/28488544","citation_count":10,"is_preprint":false},{"pmid":"40347062","id":"PMC_40347062","title":"Quercetin Induces Apoptosis Through Downregulating P4HA2 and Inhibiting the PI3K/Akt/mTOR Axis in Hepatocellular Carcinoma Cells: An In Vitro Study.","date":"2025","source":"Cancer reports (Hoboken, N.J.)","url":"https://pubmed.ncbi.nlm.nih.gov/40347062","citation_count":9,"is_preprint":false},{"pmid":"22813596","id":"PMC_22813596","title":"Profiling and comparative analysis of glycoproteins in Hs578BST and Hs578T and investigation of prolyl 4-hydroxylase alpha polypeptide II expression and influence in breast cancer cells.","date":"2012","source":"Biochemistry. 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P4ha2-/- mice showed no overt phenotype alone, but P4ha1(+/-);P4ha2(-/-) compound mutant mice exhibited chondrodysplasia, kyphosis, reduced 4-hydroxyproline content, decreased collagen II melting temperature, and biomechanically impaired extracellular matrix, demonstrating that C-P4H-I can largely compensate for C-P4H-II loss in endochondral bone development.\",\n      \"method\": \"Genetic knockout mouse models (P4ha2-/-, P4ha1+/-;P4ha2-/- compound mutants), collagen biochemistry (hydroxyproline quantification, Tm measurement), histology, atomic force microscopy\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Strong — multiple orthogonal methods (genetic KO, biochemical collagen assays, mechanical measurements) in one rigorous study with clear phenotypic readouts\",\n      \"pmids\": [\"26001784\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"HIF-1 transcriptionally upregulates P4HA2 (and P4HA1) in primary human articular chondrocytes under hypoxia (1% O2); this upregulation is abolished by the HIF-1 inhibitor 2-methoxyestradiol, indicating P4HA2 is a HIF-1 target gene that contributes to increased posttranslational collagen modification under low-oxygen conditions.\",\n      \"method\": \"Primary human chondrocyte culture under 1% O2, real-time PCR, HIF-1 inhibition with 2-methoxyestradiol, immunohistochemistry on OA cartilage\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — pharmacological HIF inhibition used to establish pathway; single lab, two methods (qPCR + IHC), but no direct ChIP or promoter assay\",\n      \"pmids\": [\"16877351\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"siRNA-mediated silencing of P4HA2 activates HIF-1, which attenuates TNF-α-induced expression of CXC chemokines (KC, LIX), CC chemokine MCP-1, and ICAM-1 in cardiomyocytes in vitro and in postischemic hearts in vivo, reducing neutrophil infiltration and myocardial infarct size by >60%; this places P4HA2 upstream of HIF-1 in cardiac ischemia-reperfusion inflammatory signaling.\",\n      \"method\": \"siRNA knockdown of P4HA2 in HL-1 cardiomyocytes and murine in vivo I/R model, cytokine/chemokine quantification, infarct size measurement, leukocyte infiltration assay\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo KD with defined phenotypic readouts; single lab, but multiple orthogonal endpoints (molecular + histological + functional)\",\n      \"pmids\": [\"17545479\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Wild-type p53 transcriptionally induces P4HA2 mRNA in glioblastoma cells (demonstrated by p53 overexpression, shRNA knockdown, and chemical induction); however, in glioblastoma this p53-driven P4HA2 mRNA upregulation does not lead to increased P4HA2 protein, increased endostatin production, or antiangiogenic effects on endothelial cells, indicating a silenced downstream signaling pathway specific to this tumor type.\",\n      \"method\": \"p53 overexpression in TP53-deleted LN-308 cells, shRNA knockdown in LNT-229 cells, camptothecin-induced p53 activation, RT-PCR, western blot, endothelial cell sprouting/viability/transmigration assays\",\n      \"journal\": \"Neuro-oncology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — three orthogonal approaches to manipulate p53 establish transcriptional regulation of P4HA2; single lab; downstream negative finding rigorously confirmed\",\n      \"pmids\": [\"20504876\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"A missense variant c.1147A>G (p.Lys383Glu) in P4HA2 reduces P4HA2 mRNA and protein expression and decreases collagen hydroxylation and deposition in primary mutant fibroblasts compared to healthy cell lines, demonstrating that P4HA2 catalytic activity is required for normal collagen hydroxylation and that loss-of-function causes myopic axial elongation.\",\n      \"method\": \"Whole-exome sequencing, in vitro studies with primary fibroblast cultures from mutation carriers vs. controls (RT-qPCR, western blot, collagen hydroxylation assay)\",\n      \"journal\": \"Clinical genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — functional in vitro validation of the variant with multiple molecular readouts; single lab, patient-derived cells\",\n      \"pmids\": [\"29364500\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Overexpression of P4HA2 in the Hs578T breast cancer cell line suppresses cell proliferation and migration, while RNA interference of P4HA2 has the opposite effect, establishing a functional role of P4HA2 in regulating breast cancer cell behavior in vitro.\",\n      \"method\": \"P4HA2 overexpression and siRNA knockdown in Hs578T cells, proliferation assays, migration assays\",\n      \"journal\": \"Biochemistry. Biokhimiia\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, single set of cell-based assays, no mechanistic pathway placement beyond the phenotype\",\n      \"pmids\": [\"22813596\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"IGF-II induces P4HA2 mRNA and protein expression in primary human lung fibroblasts via the IGF1R/IR hybrid receptor and this induction is regulated downstream in a SOX9-dependent manner, placing P4HA2 in an IGF-II→IGF1R/IR hybrid receptor→SOX9→P4HA2 profibrotic signaling axis.\",\n      \"method\": \"Primary human lung fibroblast treatment with IGF-II, receptor knockdown/inhibition, SOX9 siRNA knockdown, RT-qPCR, western blot\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 / Moderate — epistasis established by receptor and transcription factor knockdown upstream of P4HA2; single lab, multiple molecular readouts\",\n      \"pmids\": [\"37510994\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"P4HA1 and P4HA2 are required for HIF-1α translation and HIF-2α transcription and translation in VHL-deficient clear cell renal cell carcinoma (ccRCC) cells independently of pVHL; this regulation is mediated in part through P4HA1/2-driven collagen production, revealing a pVHL-independent mechanism by which collagen prolyl hydroxylases sustain HIF-α levels.\",\n      \"method\": \"P4HA1/P4HA2 knockdown/knockout in ccRCC cells, western blot for HIF-1α and HIF-2α protein, collagen production assays, pVHL-deficient cell models\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 2-3 / Weak — preprint, single lab, mechanistic details in abstract are partial; novel pVHL-independent pathway claim not yet peer-reviewed\",\n      \"pmids\": [],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"P4ha2-/- knockout mice show compromised visual acuity, time-dependent disruption of collagen fibril arrangement in sclera and cornea due to decreased collagen hydroxylation (reduced thermal stability), elevated fibronectin, and reduced collagen I in sclera/cornea; P4HA2-knockout HEK293 cells replicate the ECM imbalance, establishing that P4HA2-mediated collagen hydroxylation is required for normal scleral/corneal ECM composition and refractive function.\",\n      \"method\": \"P4ha2-/- knockout mice and P4HA2-knockout HEK293 cells (CRISPR), biometric visual assessments, electron microscopy of collagen fibrils, collagen hydroxylation quantification, western blot for fibronectin and collagen I\",\n      \"journal\": \"Human mutation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — genetic KO in two independent systems (mouse and cell line) with multiple orthogonal biochemical and structural endpoints; single lab\",\n      \"pmids\": [\"41756678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"In vitro activity assays using CRISPR-generated P4ha1-/-;P4ha2-/- cells (with P4HA3 as the only remaining isoform) showed no 4-hydroxyproline formation in type I collagen, demonstrating that P4HA3 does not hydroxylate type I collagen, and that prolyl 4-hydroxylation of type I collagen is mediated exclusively by P4HA1 and P4HA2.\",\n      \"method\": \"CRISPR/Cas9 knockout cells (P4ha3-/-, P4ha1-/-;P4ha2-/-), C-P4H activity assays, 4-hydroxyproline content measurement, collagen Tm, pepsin-resistance assay, collagen fibril assembly assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — direct enzymatic activity assay and multiple collagen biochemistry readouts in genetically defined cell lines; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"41999892\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Quercetin downregulates P4HA2 expression in hepatocellular carcinoma (HCC) cells, and P4HA2 knockdown enhances quercetin-induced apoptosis; the apoptotic effect is mediated through inhibition of the PI3K/Akt/mTOR pathway, placing P4HA2 upstream of this survival signaling axis in HCC cells.\",\n      \"method\": \"P4HA2 siRNA knockdown in HCC cells, quercetin treatment, PI3K/Akt/mTOR pathway inhibitors (LY294002, Z-VAD-FMK) and activator (740Y-P), cell viability and apoptosis assays\",\n      \"journal\": \"Cancer reports (Hoboken, N.J.)\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, pharmacological pathway dissection without direct biochemical reconstitution; mechanistic link between P4HA2 and PI3K/Akt is indirect\",\n      \"pmids\": [\"40347062\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"BMAL1 knockdown reduces P4HA2 and COL2A1 expression in both macroscopically normal and OA chondrocytes under high-glucose conditions, placing P4HA2 downstream of the circadian clock transcription factor BMAL1 in a glucose-responsive collagen synthesis pathway.\",\n      \"method\": \"Primary human chondrocyte culture under high glucose, BMAL1 siRNA knockdown, RT-qPCR, western blot, secreted collagen II quantification\",\n      \"journal\": \"Osteoarthritis and cartilage open\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, siRNA epistasis shows BMAL1 regulates P4HA2 but no direct promoter or binding evidence; single method per finding\",\n      \"pmids\": [\"41630778\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"P4HA2 encodes the catalytic α-subunit of collagen prolyl 4-hydroxylase isoenzyme II (C-P4H-II), an α2β2 tetramer that catalyzes hydroxylation of proline residues in collagen chains to 4-hydroxyproline, which is essential for collagen triple-helix formation, thermal stability, and proper extracellular matrix assembly; P4HA2 is transcriptionally induced by HIF-1 under hypoxia and by p53, regulated downstream of IGF-II/SOX9 and BMAL1 signaling axes, functionally redundant with P4HA1 in most tissues (but not replaceable by P4HA3 for type I collagen), and required in vivo for normal scleral/corneal collagen organization, chondrocyte-mediated endochondral bone development, and—in ccRCC—for pVHL-independent maintenance of HIF-1α and HIF-2α levels through collagen production.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"P4HA2 encodes the catalytic α-subunit of collagen prolyl 4-hydroxylase isoenzyme II (C-P4H-II), an α2β2 tetrameric enzyme that converts proline residues in collagen chains to 4-hydroxyproline, a modification required for collagen triple-helix formation and thermal stability [#0]. Together with P4HA1, P4HA2 accounts entirely for prolyl 4-hydroxylation of type I collagen, as the remaining isoform P4HA3 cannot hydroxylate type I collagen [#9]; C-P4H-I can largely compensate for loss of C-P4H-II in endochondral bone development, but compound loss produces chondrodysplasia, reduced 4-hydroxyproline content, and biomechanically impaired matrix [#0]. P4HA2-dependent hydroxylation is required for normal extracellular matrix composition in vivo: loss of P4HA2 disrupts scleral and corneal collagen fibril arrangement, lowers collagen thermal stability, elevates fibronectin, reduces collagen I, and compromises visual acuity [#8], and a loss-of-function missense variant that reduces P4HA2 expression and collagen hydroxylation underlies myopic axial elongation [#4]. Transcriptionally, P4HA2 is induced by HIF-1 under hypoxia [#1] and by wild-type p53 [#3], and is regulated downstream of an IGF-II→IGF1R/IR hybrid receptor→SOX9 profibrotic axis in lung fibroblasts [#6]. Beyond these collagen-modifying and regulatory roles, the broader signaling context captured here is limited to individual cell-type studies.\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Established that P4HA2 is an oxygen-responsive gene, linking collagen post-translational modification capacity to hypoxic signaling.\",\n      \"evidence\": \"Primary human chondrocytes under 1% O2 with qPCR and pharmacological HIF-1 inhibition\",\n      \"pmids\": [\"16877351\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct ChIP or promoter-binding evidence for HIF-1 occupancy\", \"Pharmacological inhibitor may have off-target effects\", \"Limited to chondrocytes\"]\n    },\n    {\n      \"year\": 2007,\n      \"claim\": \"Placed P4HA2 upstream of HIF-1 in cardiac inflammatory signaling, indicating its loss can feed back into HIF-driven transcription with functional cardioprotective consequences.\",\n      \"evidence\": \"siRNA knockdown in HL-1 cardiomyocytes and murine ischemia-reperfusion model with chemokine, infarct-size, and leukocyte readouts\",\n      \"pmids\": [\"17545479\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which P4HA2 loss activates HIF-1 not resolved\", \"Single lab\", \"Relationship to collagen hydroxylation activity unclear\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Showed P4HA2 is a transcriptional target of wild-type p53, while revealing tumor-type-specific uncoupling of mRNA induction from protein output.\",\n      \"evidence\": \"p53 overexpression, shRNA knockdown, and chemical induction in glioblastoma cells with RT-PCR and western blot\",\n      \"pmids\": [\"20504876\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Cause of the mRNA-to-protein uncoupling not identified\", \"No direct p53 promoter-binding assay\", \"Single tumor context\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Reported a context-dependent role for P4HA2 in regulating breast cancer cell proliferation and migration.\",\n      \"evidence\": \"Overexpression and siRNA knockdown in Hs578T cells with proliferation and migration assays\",\n      \"pmids\": [\"22813596\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No mechanistic pathway placement beyond phenotype\", \"Single cell line, single lab\", \"Direction of effect not linked to collagen hydroxylation\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined P4HA2's enzymatic identity and its functional redundancy with P4HA1, establishing C-P4H-II as the chondrocyte-predominant collagen prolyl 4-hydroxylase whose loss is largely compensable.\",\n      \"evidence\": \"P4ha2-/- and P4ha1+/-;P4ha2-/- mouse models with hydroxyproline quantification, collagen Tm, histology and atomic force microscopy\",\n      \"pmids\": [\"26001784\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Degree of redundancy in non-chondrocyte tissues not fully mapped\", \"Substrate selectivity between isoforms not defined\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated that P4HA2 catalytic activity is required for normal collagen hydroxylation in humans, linking loss-of-function to myopic axial elongation.\",\n      \"evidence\": \"Whole-exome sequencing plus patient-derived fibroblast assays (RT-qPCR, western blot, collagen hydroxylation)\",\n      \"pmids\": [\"29364500\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single family/variant\", \"No animal rescue of the specific variant\", \"Mechanism connecting reduced hydroxylation to ocular axial growth not detailed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Positioned P4HA2 within an IGF-II→IGF1R/IR hybrid receptor→SOX9 profibrotic axis in lung fibroblasts.\",\n      \"evidence\": \"Primary human lung fibroblasts with IGF-II treatment, receptor knockdown/inhibition, SOX9 siRNA, RT-qPCR and western blot\",\n      \"pmids\": [\"37510994\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct SOX9 promoter-binding evidence at P4HA2\", \"Single lab\", \"In vivo fibrosis relevance not established\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Proposed a pVHL-independent mechanism whereby P4HA1/2-driven collagen production sustains HIF-1α and HIF-2α levels in VHL-deficient ccRCC.\",\n      \"evidence\": \"P4HA1/P4HA2 knockdown/knockout in ccRCC cells with HIF-α western blots and collagen production assays (preprint)\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Mechanistic link between collagen production and HIF-α translation/transcription only partial\", \"Single lab\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Linked P4HA2 to PI3K/Akt/mTOR survival signaling and quercetin-induced apoptosis in hepatocellular carcinoma cells.\",\n      \"evidence\": \"siRNA knockdown with quercetin treatment and pharmacological pathway modulators in HCC cells; viability and apoptosis assays\",\n      \"pmids\": [\"40347062\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Mechanistic link between P4HA2 and PI3K/Akt is indirect\", \"No biochemical reconstitution\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Established that P4HA2-mediated collagen hydroxylation is required for proper scleral/corneal ECM composition and refractive function in vivo.\",\n      \"evidence\": \"P4ha2-/- mice and CRISPR P4HA2-knockout HEK293 cells with electron microscopy, hydroxylation quantification and western blots\",\n      \"pmids\": [\"41756678\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting fibronectin elevation/collagen I reduction not fully resolved\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Showed that prolyl 4-hydroxylation of type I collagen is mediated exclusively by P4HA1 and P4HA2, with P4HA3 unable to substitute.\",\n      \"evidence\": \"CRISPR P4ha3-/- and P4ha1-/-;P4ha2-/- cells with direct C-P4H activity assays, hydroxyproline, collagen Tm, pepsin-resistance and fibril assembly assays\",\n      \"pmids\": [\"41999892\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Isoform-specific substrate preferences across collagen types not fully mapped\", \"Single lab\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"Placed P4HA2 downstream of the circadian transcription factor BMAL1 in a glucose-responsive collagen synthesis pathway in chondrocytes.\",\n      \"evidence\": \"BMAL1 siRNA knockdown in primary human chondrocytes under high glucose with RT-qPCR, western blot and collagen II quantification\",\n      \"pmids\": [\"41630778\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No direct BMAL1 promoter-binding evidence\", \"Single method per readout\", \"Single lab\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How the multiple upstream transcriptional inputs (HIF-1, p53, SOX9, BMAL1) are integrated to set P4HA2-dependent collagen hydroxylation in specific tissues, and the precise mechanism linking P4HA2/collagen production to HIF-α stabilization, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No unified model integrating the distinct transcriptional regulators\", \"pVHL-independent HIF-α mechanism unconfirmed in peer review\", \"Tissue-specific isoform redundancy incompletely mapped\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016491\", \"supporting_discovery_ids\": [0, 9]},\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 4, 9]}\n    ],\n    \"localization\": [],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [0, 8]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 9]}\n    ],\n    \"complexes\": [\"collagen prolyl 4-hydroxylase (C-P4H-II)\"],\n    \"partners\": [\"P4HA1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":4,"faith_total":4,"faith_pct":100.0}}