{"gene":"REN","run_date":"2026-04-28T19:45:45","timeline":{"discoveries":[{"year":1983,"finding":"The primary structure of human renin precursor was deduced from cDNA sequencing, revealing a 406-amino acid preprorenin with a 20-amino acid pre-segment and 46-amino acid pro-segment, with high sequence homology to mouse renin and structural similarity to aspartyl proteinases.","method":"cDNA library screening, nucleotide sequencing, sequence homology analysis","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 — direct cDNA sequencing with full structural characterization; foundational paper (285 citations)","pmids":["6324167"],"is_preprint":false},{"year":1984,"finding":"The human renin gene spans ~12 kb of DNA, contains 9 exons (encoding a 403-amino acid preprorenin) interrupted by 8 introns, with a TATA box promoter and glucocorticoid-response-like elements ~200–300 bp upstream; its structure is evolutionarily related to pepsinogen, and there is a single copy in the human genome.","method":"Genomic DNA cloning, restriction mapping, DNA sequencing, hybridization with mouse renin cDNA and synthetic oligonucleotide probes","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 1 — complete gene structure determined by sequencing; replicated by independent group (Hardman et al. same year)","pmids":["6089171","6391881"],"is_preprint":false},{"year":1984,"finding":"Mouse Ren-1 and Ren-2 genes exhibit markedly different tissue-specific expression patterns despite conserved proximal promoter elements; a repetitive DNA element (IAP retroviral provirus) and sequence differences ~150 bp upstream of the transcription start site distinguish the Ren-2 copy, and tissue-specific utilization of homologous transcription start sites underlies their differential expression.","method":"Genomic sequencing, S1 nuclease analysis, comparative 5'-flanking region analysis, Northern blot","journal":"Molecular and cellular biology","confidence":"High","confidence_rationale":"Tier 1 — direct sequencing and functional mapping of transcription initiation; foundational mechanistic study","pmids":["6392850"],"is_preprint":false},{"year":1984,"finding":"A complete intra-cisternal A particle (IAP) retroviral genome (MIARN) was identified within the Ren-2 locus of DBA/2 mice, flanking the 5' LTR with a phenylalanine tRNA-complementary sequence required for minus-strand synthesis initiation; this retroviral association may contribute to the high expression of Ren-2.","method":"Complete nucleotide sequencing of IAP genome, structural analysis of LTRs and tRNA binding site","journal":"Nucleic acids research","confidence":"Medium","confidence_rationale":"Tier 1 — complete sequence; mechanistic link to Ren-2 expression is inferred rather than directly demonstrated","pmids":["6095203"],"is_preprint":false},{"year":1985,"finding":"Both Ren-1 and Ren-2 loci are expressed in the kidney of two-gene mouse strains at approximately equal mRNA levels, demonstrated using reverse transcriptase-mediated primer extension assays exploiting base sequence differences between the two highly homologous transcripts.","method":"Reverse transcriptase-mediated primer extension with dideoxynucleotide discrimination, oligonucleotide primer-based allele-specific assay","journal":"Proceedings of the National Academy of Sciences of the United States of America","confidence":"High","confidence_rationale":"Tier 2 — direct allele-specific quantification with two orthogonal methods","pmids":["3898081"],"is_preprint":false},{"year":1988,"finding":"Physical mapping by pulsed-field gel electrophoresis revealed that mouse Ren-1 and Ren-2 are separated by ~20 kb of DNA, transcribed in the same orientation, with Ren-2 upstream of Ren-1, within a ~120 kb genomic region on chromosome 1.","method":"Pulsed-field gel electrophoresis, restriction mapping","journal":"Nucleic acids research","confidence":"High","confidence_rationale":"Tier 1 — direct physical mapping with PFGE","pmids":["2833727"],"is_preprint":false},{"year":1989,"finding":"The complete nucleotide sequence of mouse Ren-1d was determined; all three renin genes (Ren-1c, Ren-1d, Ren-2d) span ~9.6 kb with 9 exons and 8 introns, with significant sequence differences in their 5'-flanking regions that likely underlie differential regulation.","method":"Complete genomic DNA sequencing, comparative sequence analysis of 5'-flanking regions","journal":"Gene","confidence":"High","confidence_rationale":"Tier 1 — complete gene sequence with comparative structural analysis","pmids":["2691339"],"is_preprint":false},{"year":1989,"finding":"Expression of the DBA/2J Ren-2 transgene in mice was restricted to the X-zone of the adrenal gland (rather than cycling between X-zone and zona fasciculata as in native DBA/2 mice), demonstrating that cell-specific adrenal expression of Ren-2 is mediated in trans by at least one additional locus not present in the host genome.","method":"Transgenic mouse generation, tissue expression analysis, hormonal control experiments, genetic crosses","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 — transgenic complementation with genetic crosses revealing trans-regulation","pmids":["2480233"],"is_preprint":false},{"year":1989,"finding":"The two Ren-1 alleles (Ren-1c and Ren-1d) exhibit characteristic, allele-specific expression patterns in adrenal gland, testis, and sex accessory gland tissue that are regulated by closely associated cis-acting sequences, as demonstrated by allele-specific dideoxynucleotide primer extension assays and genetic analysis.","method":"Allele-specific dideoxynucleotide primer extension assay, genetic analysis of one- vs two-gene mouse strains","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 — allele-specific assay with genetic epistasis analysis across multiple tissues","pmids":["2677011"],"is_preprint":false},{"year":1989,"finding":"The crystal structure of recombinant human renin was determined at 2.5 Å resolution, revealing that renin is an aspartyl proteinase with a highly conserved structural core and active site compared to other aspartyl proteinases, but with variable surface loops that confer substrate specificity; this structural knowledge enabled rational inhibitor design.","method":"X-ray crystallography with molecular dynamics refinement","journal":"Science","confidence":"High","confidence_rationale":"Tier 1 — crystal structure at 2.5 Å with functional implications; 191 citations","pmids":["2493678"],"is_preprint":false},{"year":1990,"finding":"Introduction of the mouse Ren-2 renin gene into the rat genome caused severe fulminant hypertension without overexpression of active renin in the kidney or elevated plasma active renin, establishing that extrarenal expression of a renin gene is sufficient to cause severe hypertension and providing a model of low-renin hypertension.","method":"Transgenic rat generation, blood pressure measurement, renin activity assays","journal":"Nature","confidence":"High","confidence_rationale":"Tier 2 — transgenic gain-of-function with defined genetic lesion; 840 citations, replicated by multiple groups","pmids":["2181319"],"is_preprint":false},{"year":1990,"finding":"Mouse Ren-2 prorenin (42 kDa, pI 6.5) was purified from transfected Chinese hamster ovary cells; amino-terminal sequencing confirmed the predicted prorenin sequence from the Ren-2 preprorenin cDNA, establishing that CHO cells secrete the correctly processed prorenin form.","method":"CHO cell transfection, multi-step chromatographic purification (DEAE-Toyopearl, Blue-Toyopearl, isoelectric focusing), SDS-PAGE, amino-terminal sequencing","journal":"Journal of biochemistry","confidence":"High","confidence_rationale":"Tier 1 — protein purification with biochemical characterization and sequence validation","pmids":["2202716"],"is_preprint":false},{"year":1991,"finding":"Substrate (angiotensinogen) paucity in Mus, consistent with first-order kinetics, phenotypically inhibits the renin-angiotensin system and was a prerequisite for the evolutionary emergence of enhanced Ren-2 expression in the submandibular gland; intravenous angiotensinogen injection markedly raised blood pressure, demonstrating that substrate limitation normally constrains renin activity.","method":"Comparative physiological experiments, intravenous substrate injection, blood pressure measurement across Mus strains","journal":"General and comparative endocrinology","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo functional demonstration of substrate limitation; single study","pmids":["1916217"],"is_preprint":false},{"year":1992,"finding":"The mouse Ren-2 transgene is expressed in vascular (mesenteric and aortic) tissue of transgenic rats, leading to substantially increased vascular angiotensin I and II formation (measured by HPLC and RIA from perfused hindquarters); bilateral nephrectomy abolished angiotensin release in controls but not transgenic rats, establishing that vascular Ren-2 expression drives local angiotensin formation independent of kidney renin.","method":"Isolated perfused hindquarter preparation, HPLC, radioimmunoassay, RNase protection assay, Northern blot, bilateral nephrectomy","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods (perfusion, RIA, RNase protection, Northern, nephrectomy) in same study","pmids":["1592469"],"is_preprint":false},{"year":1992,"finding":"Prorenin is markedly elevated in plasma of Ren-2 transgenic rats despite suppressed active renin and angiotensin levels; hypertension is driven by angiotensin II and is extremely sensitive to ACE inhibitor (captopril) treatment, and sodium depletion normalizes blood pressure, implicating a volume-dependent/adrenal renin-angiotensin component.","method":"Transgenic rat model, blood pressure monitoring, ACE inhibitor treatment, sodium depletion protocol, prorenin/renin assays","journal":"Kidney international. Supplement","confidence":"Medium","confidence_rationale":"Tier 2 — pharmacological dissection in transgenic model; single study","pmids":["1630068"],"is_preprint":false},{"year":1992,"finding":"Prorenin is converted to active renin by the convertase PC1 in a cell-type-specific manner requiring secretory granules (demonstrated in GH4 somatomammotroph cells), but not by PC2 or furin, and not in cells lacking granules (CHO, BSC-40 cells); this establishes the intracellular compartment as a critical determinant of prorenin processing.","method":"Vaccinia virus expression system, biosynthetic labeling, cell-type comparison (GH4 vs CHO/BSC-40), immunoprecipitation","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — reconstitution-type experiment with multiple cell lines and convertases; 155 citations","pmids":["1597471"],"is_preprint":false},{"year":1993,"finding":"Renin mRNA is expressed in multiple human tissues (kidney, adrenal gland, placenta, saphenous vein) as quantified by competitive PCR using a deletion-mutant internal standard; kidney has the highest renin mRNA concentration, followed by adrenal, placenta, and vein.","method":"Reverse transcription-PCR, competitive quantitative PCR with internal deletion-mutant standard","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 1 — quantitative PCR with rigorous internal standard; 224 citations","pmids":["8387539"],"is_preprint":false},{"year":1993,"finding":"The Ren-2 transgene in TGR(mREN2)27 rats is expressed in cardiovascular-regulatory organs (adrenal, kidney, brain) before hypertension develops; hypertension is associated with decreased plasma angiotensin I and near-undetectable angiotensin-(1-7), and is mediated by the renin-angiotensin system since ACE inhibition and AT1 blockade normalize blood pressure, with nitric oxide contributing more in transgenic than normotensive rats.","method":"Transgenic rat model, plasma angiotensin peptide measurement, lisinopril/losartan pharmacological intervention, L-NMMA injection, RNase protection assay","journal":"The American journal of physiology","confidence":"High","confidence_rationale":"Tier 2 — pharmacological dissection with multiple interventions; replicated across multiple papers","pmids":["8238495","8184972"],"is_preprint":false},{"year":1994,"finding":"In Ren-2 transgenic hypertensive rats, central (intracerebroventricular) administration of angiotensin II or angiotensin-(1-7) increases local vasopressin (AVP) release from paraventricular and supraoptic nuclei in control but not transgenic rats, demonstrating that insertion of the mouse renin gene alters the brain angiotensin-vasopressin axis; transgenic rats showed 22-fold higher AVP in the dorsal lower brain stem.","method":"Brain microdialysis, intracerebroventricular infusion, radioimmunoassay of AVP and angiotensin peptides","journal":"The American journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 — direct microdialysis measurement with pharmacological challenge; single study","pmids":["8092324"],"is_preprint":false},{"year":1994,"finding":"In Ren-2 transgenic rat coronary arteries, hypertension selectively abolishes endothelium-dependent contractions in response to L-NAME (NOS inhibition), while endothelium-dependent relaxations to acetylcholine and smooth muscle function remain intact, indicating a selective impairment of EDNO-dependent contractile tone.","method":"Isolated coronary artery myograph/organ chamber preparation, isometric tension recording, pharmacological dissection with L-NAME, SQ30741","journal":"Circulation","confidence":"Medium","confidence_rationale":"Tier 2 — ex vivo vascular preparation with pharmacological dissection; single study","pmids":["8205692"],"is_preprint":false},{"year":1995,"finding":"Tubuloglomerular feedback (TGF) responses in Ren-2 transgenic hypertensive rats are enhanced and ~84% dependent on angiotensin II acting via AT1 receptors (blocked by L-158,809), with only ~43% of the attenuation attributable to blood pressure reduction alone, establishing a direct role for locally generated angiotensin II in sensitizing the TGF mechanism.","method":"Stop-flow pressure micropuncture, AT1 receptor antagonist administration, mechanical renal arterial pressure reduction","journal":"The American journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo micropuncture with pharmacological and mechanical dissection; single study","pmids":["7771510"],"is_preprint":false},{"year":1996,"finding":"Targeted inactivation of the mouse Ren-2 gene showed that mice lacking Ren-2 are viable and normotensive, with increased active renin and decreased prorenin in plasma; the Ren-1d gene alone is sufficient to regulate normal blood pressure, demonstrating that Ren-2 is functionally redundant for blood pressure control despite differing tissue expression.","method":"Gene targeting/knockout, blood pressure measurement, plasma renin and prorenin quantification, histopathological analysis","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 1-2 — definitive loss-of-function with phenotypic characterization; clean genetic experiment","pmids":["8952610"],"is_preprint":false},{"year":1998,"finding":"In female Ren-2 transgenic rats, adrenal angiotensin II is significantly elevated compared to controls, while kidney angiotensin II is unchanged but angiotensin I and angiotensin-(1-7) are lower; cardiac angiotensin I, II, and angiotensin-(2-10) are reduced while angiotensin-(2-7) is increased. Tissue angiotensins cycle with estrous stage in both strains, establishing organ-specific angiotensin II generation patterns driven by the Ren-2 transgene.","method":"HPLC, radioimmunoassay of multiple angiotensin peptides from adrenal, kidney, and heart tissue","journal":"Peptides","confidence":"Medium","confidence_rationale":"Tier 2 — HPLC + RIA with multiple peptide measurements; single study","pmids":["9880073"],"is_preprint":false},{"year":1998,"finding":"Concomitant with elevated adrenal renin activity in TGR(mREN2)27 rats, adrenocortical steroid production is elevated and aldosterone regulation is impaired; since kidney and plasma renin and angiotensins are low, these findings establish a functional role for the local adrenal renin-angiotensin system (driven by Ren-2) in controlling aldosterone production.","method":"Adrenal renin activity measurement, steroid and aldosterone assays, comparison with plasma/kidney renin levels in transgenic vs control rats","journal":"Hormone and metabolic research","confidence":"Medium","confidence_rationale":"Tier 2 — functional endocrine measurements in transgenic model with appropriate controls; single study","pmids":["9694562"],"is_preprint":false},{"year":1999,"finding":"AT1 receptor binding is significantly increased in glomeruli, proximal tubules, and inner stripe of outer medulla of Ren-2 transgenic hypertensive rats (but not AT2 receptors), mainly in vascular smooth muscle of intrarenal vessels, juxtaglomerular apparatus, mesangial cells, and proximal tubular cells; AT1 blockade with losartan markedly reduced mean arterial pressure and increased renal blood flow in transgenic but not control rats, establishing that upregulated intrarenal AT1 receptors mediate the renal hemodynamic effects of elevated angiotensin II.","method":"In vitro autoradiography of renal AT1/AT2 receptors, immunohistochemistry, renal hemodynamics measurement, AT1/AT2 receptor blockade","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 2 — receptor mapping with multiple methods (autoradiography, IHC, pharmacology) in vivo and ex vivo","pmids":["9931128"],"is_preprint":false},{"year":1999,"finding":"Ren-2 hypertensive transgenic rats exhibit exaggerated renal vascular responsiveness specifically to angiotensin II (but not to norepinephrine or vasodilators), with intrarenal angiotensin II causing larger decreases in renal blood flow than in normotensive controls, establishing a selective enhancement of angiotensin II-mediated renal vasoconstriction.","method":"Intravenous and intrarenal arterial angiotensin II administration, renal blood flow measurement, pharmacological comparison with norepinephrine, bradykinin, and acetylcholine","journal":"The American journal of physiology","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo pharmacological dose-response; selectivity demonstrated by comparison with other vasoconstrictors","pmids":["9950963"],"is_preprint":false},{"year":2000,"finding":"BAC transgenesis of a 145 kb region encompassing both Ren-1d and Ren-2 loci completely rescued juxtaglomerular cell granulation and macula densa morphology in Ren-1d-null mice; homologous recombination inserting an IRES-β-geo marker into Ren-1d confirmed that juxtaglomerular cells express Ren-1d throughout development even without granulation, and that Ren-2 overexpression cannot functionally compensate for loss of Ren-1d, establishing primary structural differences between the two isoforms as responsible for differential granulation.","method":"BAC transgenesis, homologous recombination in E. coli (piggy-BAC), backcross genetic complementation, lacZ reporter expression, histological analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — genetic complementation with reporter insertion and null background; multiple orthogonal approaches","pmids":["10995772"],"is_preprint":false},{"year":2001,"finding":"Expression from the mouse Ren-1c gene requires a proximal promoter element (PPE at ~-60) that is an Abd-B class HOX·PBX binding consensus sequence (TAATAAATCAA); Abd-B HOX members (HOXD10, HOXA10, HOXA9, HOXB9, HOXC9) bind this element with or without PBX1b, and point mutations in either the HOX or PBX half-site dramatically decreased Ren-1c transcriptional activity; PBX1b, PREP1, and HOX form a ternary complex on the PPE both in vivo and in vitro.","method":"Electrophoretic mobility shift assay, in vitro binding assays, point mutagenesis, transfection-based transcriptional activity assays, in vivo DNA binding studies in As4.1 cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — direct mutagenesis of binding sites with functional readout; reconstituted ternary complex in vitro and in vivo","pmids":["11432851"],"is_preprint":false},{"year":2002,"finding":"Renin and prorenin binding to the cloned (pro)renin receptor (a 350-amino acid single transmembrane domain protein) increases the catalytic efficiency of angiotensin I generation from angiotensinogen fourfold and induces intracellular signaling (phosphorylation of serine/tyrosine residues and ERK1/2 activation) independently of angiotensin II; the receptor is localized by confocal microscopy to glomerular mesangium and subendothelium of coronary and kidney arteries, co-localizing with renin.","method":"Expression cloning, stable transfection, specific binding assay, angiotensinogen conversion kinetics, MAP kinase phosphorylation assay, confocal microscopy","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 1 — reconstituted receptor binding with enzymatic kinetics + signaling assays + localization; 1101 citations","pmids":["12045255"],"is_preprint":false},{"year":2003,"finding":"Human prorenin has a 'gate' region (T7PFKR10P) and 'handle' region (I11PFLKR15P) in the prosegment that are critical for its non-proteolytic activation; antibodies targeting the handle region (anti-11/26) non-proteolytically activate 90% of prorenin at 4°C, and acid-activated prorenin exposes both regions for antibody binding; handle- and gate-region antibodies prevent re-inactivation, defining the molecular mechanism of reversible prorenin activation.","method":"Antibody-based non-proteolytic activation assay, acid-activation/re-inactivation experiments, equilibrium dissociation constant determination, tertiary structure-guided antigen design","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — mechanistic dissection with five region-specific antibodies; reconstituted activation/inactivation cycle; 154 citations","pmids":["12684512"],"is_preprint":false},{"year":2004,"finding":"Renin-expressing cells in the brain were identified using an eGFP reporter transgene driven by the mouse renin promoter; eGFP-positive cells were found in cerebellum, hippocampus, dorsal motor nucleus of the vagus, inferior olivary nucleus, reticular formation, rostral ventrolateral medulla, central nucleus of the amygdala, lateral parabrachial nucleus, mesencephalic trigeminal nucleus, bed nucleus of stria terminalis, and subfornical organ; co-labeling confirmed these cells are predominantly neuronal.","method":"eGFP reporter transgenic mouse, fluorescence microscopy, co-immunolabeling with neuron- and glia-specific antisera","journal":"Physiological genomics","confidence":"High","confidence_rationale":"Tier 2 — direct reporter-based localization with cell-type co-labeling; identifies specific brain nuclei","pmids":["14625376"],"is_preprint":false},{"year":2005,"finding":"Loss-of-function mutations in renin (REN), angiotensinogen, ACE, or angiotensin II type 1 receptor cause autosomal recessive renal tubular dysgenesis, characterized by fetal anuria and absence of differentiated proximal tubules; this establishes that REN activity and the renin-angiotensin system are essential for human renal tubular development.","method":"Linkage analysis, candidate gene sequencing, homozygosity/compound heterozygosity mapping in 9 families with 11 affected individuals","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 — human genetic loss-of-function with defined molecular lesion across multiple families; 182 citations","pmids":["16116425"],"is_preprint":false},{"year":2006,"finding":"Prorenin and renin binding to the (pro)renin receptor in human monocytes (U937 cells) induces long-lasting ERK1/2 phosphorylation independently of angiotensin II (persisting with AT1 and AT2 receptor blockade), via MEK1/2-dependent signaling; this signaling is distinct from angiotensin II-ERK signaling (not involving EGF receptor transactivation). Aliskiren (direct renin inhibitor) does not block (pro)renin receptor binding or ERK1/2 activation.","method":"Immunoprecipitation, Western blot for phospho-ERK1/2, receptor binding with 125I-labeled renin/prorenin, AT1/AT2 blockade, MEK inhibitor, FACS analysis","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 1-2 — multiple orthogonal methods; receptor binding + signaling pathway dissection with pharmacological controls; 186 citations","pmids":["18212269"],"is_preprint":false},{"year":2006,"finding":"Prorenin activates p38 MAPK and phosphorylates HSP27 in neonatal rat cardiomyocytes through the (pro)renin receptor, independently of angiotensin II (not blocked by aliskiren or AT1 antagonist eprosartan); this leads to transcriptional regulation of ~260 genes including those involved in actin filament dynamics and results in actin cytoskeleton remodeling.","method":"p38 MAPK phosphorylation assay, SB203580 (p38 inhibitor) blocking experiment, microarray gene expression profiling (4800 genes), quantitative RT-PCR, 2D proteomics, immunoblotting","journal":"Hypertension","confidence":"High","confidence_rationale":"Tier 1-2 — mechanistic pathway (p38/HSP27) with inhibitor blocking, microarray, proteomics; 198 citations","pmids":["16940215"],"is_preprint":false},{"year":2007,"finding":"ACE2 is the primary enzyme responsible for cardiac angiotensin-(1-7) generation from angiotensin II in hypertrophic hearts of Ren-2 hypertensive rats; ACE2 inhibition (MLN-4760) reduced cardiac angiotensin-(1-7) production by 83% in hypertensive but had no significant effect in normotensive hearts, demonstrating a compensatory upregulation of cardiac ACE2 in hypertension.","method":"Langendorff isolated heart preparation, HPLC-RIA angiotensin peptide measurement, pharmacological ACE2 inhibition, ACE2 activity assay, Western blot for ACE2 protein","journal":"American journal of physiology. Heart and circulatory physiology","confidence":"High","confidence_rationale":"Tier 1-2 — ex vivo organ preparation with pharmacological inhibition and protein quantification","pmids":["17308000"],"is_preprint":false},{"year":2009,"finding":"Dominant mutations in the signal sequence of human renin (p.Leu16del, p.Leu16Arg) reduce signal peptide hydrophobicity, impair ER translocation and processing of preprorenin, resulting in reduced or abolished prorenin/renin biosynthesis and secretion; cells expressing p.Leu16del show activated ER stress, unfolded protein response, and reduced growth rate, causing progressive juxtaglomerular cell loss and autosomal dominant kidney disease.","method":"Linkage analysis, candidate gene sequencing, transfection studies, in vitro translation, ER translocation assay, ER stress markers (Western blot), cell growth assay, kidney biopsy immunohistochemistry","journal":"American journal of human genetics","confidence":"High","confidence_rationale":"Tier 1 — reconstituted ER translocation defect with in vitro and cell-based validation + human genetic evidence; 121 citations","pmids":["19664745"],"is_preprint":false},{"year":2010,"finding":"The crystal structure of human angiotensinogen at 2.1 Å reveals that the angiotensin cleavage site is inaccessibly buried in its amino-terminal tail; a 4.4 Å structure of the angiotensinogen-renin complex reveals the conformational rearrangement (linked by a conserved disulphide bridge) required for renin to access and cleave the substrate. The oxidized (sulphydryl-bridged) form of angiotensinogen preferentially interacts with receptor-bound renin, and the reduced:oxidized ratio is ~40:60 in circulation, rising in pre-eclampsia.","method":"X-ray crystallography (2.1 Å angiotensinogen alone; 4.4 Å complex with renin), redox state analysis of circulating angiotensinogen, pre-eclampsia patient samples","journal":"Nature","confidence":"High","confidence_rationale":"Tier 1 — crystal structures of substrate alone and in complex with renin, revealing mechanism of substrate recognition; 155 citations","pmids":["20927107"],"is_preprint":false},{"year":2011,"finding":"miR-663 and miR-181a bind to the 3'-UTR of the REN mRNA and regulate renin mRNA levels in human kidney (HEK293) cells, as demonstrated by luciferase reporter gene experiments; in hypertensive human kidneys, two miRNAs are downregulated, potentially explaining elevated intrarenal renin mRNA.","method":"Microarray transcriptomics, quantitative RT-PCR validation, luciferase reporter assay with REN 3'-UTR in HEK293 cells, miRNA transfection","journal":"Hypertension","confidence":"Medium","confidence_rationale":"Tier 2 — direct 3'-UTR luciferase reporter assay with miRNA transfection; single study in cell line","pmids":["22042811"],"is_preprint":false},{"year":2020,"finding":"An international cohort study of 111 individuals from 30 families with ADTKD-REN defined three pathophysiologically distinct subtypes based on mutation location: (1) signal peptide mutations reduce hydrophobicity required for ER recognition/translocation, leading to aberrant cytoplasmic delivery of preprorenin; (2) prosegment mutations cause prorenin/renin deposition in the ER-Golgi intermediate compartment with decreased secretion; (3) mature renin mutations cause mutant prorenin deposition in the ER (similar to ADTKD-UMOD), with slowest progression to end-stage kidney disease.","method":"International cohort clinical study, genotyping of 30 families, signal peptide hydrophobicity analysis, cellular trafficking studies (ER-Golgi localization), secretion assays, survival analysis","journal":"Kidney international","confidence":"High","confidence_rationale":"Tier 2 — large multi-family cohort with mechanistic cellular studies; three distinct mechanisms validated","pmids":["32750457"],"is_preprint":false}],"current_model":"Human renin (REN) is an aspartyl protease whose crystal structure (2.5 Å) reveals a conserved catalytic core with variable surface loops conferring specificity; it is synthesized as preprorenin (signal peptide + 46-aa prosegment required for ER translocation), processed to prorenin in the secretory pathway by the convertase PC1 in a secretory granule-dependent manner, and can be non-proteolytically activated by displacement of the prosegment 'gate' and 'handle' regions; active renin cleaves angiotensinogen (whose angiotensin site is normally buried but exposed upon conformational change linked to a redox-responsive disulphide bridge) to generate angiotensin I; renin and prorenin also bind the (pro)renin receptor, which increases catalytic efficiency fourfold and triggers angiotensin II-independent ERK1/2 and p38 MAPK/HSP27 signaling; transcription of Ren-1c requires Abd-B HOX·PBX·PREP1 ternary complexes at a proximal promoter element; renin mRNA is regulated post-transcriptionally by miR-663 and miR-181a; dominant signal-peptide mutations cause ER translocation failure and ER stress leading to ADTKD, while prosegment mutations trap prorenin in the ER-Golgi compartment, and mature-renin mutations deposit mutant protein in the ER."},"narrative":{"teleology":[{"year":1983,"claim":"Determination of the full preprorenin primary structure from cDNA established that renin is synthesized as a 406-amino-acid precursor with a signal peptide and prosegment homologous to aspartyl proteinases, resolving the biosynthetic origin of circulating renin.","evidence":"cDNA library screening and nucleotide sequencing of human kidney renin mRNA","pmids":["6324167"],"confidence":"High","gaps":["No three-dimensional structural information yet available","Processing mechanism of the prosegment unknown","Tissue-specific transcriptional regulation not addressed"]},{"year":1984,"claim":"Elucidation of the human REN gene structure (9 exons, single copy, ~12 kb) and comparative analysis of mouse Ren-1/Ren-2 loci revealed conserved organization with divergent 5′-flanking regions, providing the framework for understanding tissue-specific and allele-specific transcriptional regulation.","evidence":"Genomic DNA cloning, restriction mapping, and complete sequencing of human and mouse renin loci; S1 nuclease mapping of transcription start sites","pmids":["6089171","6391881","6392850"],"confidence":"High","gaps":["Specific transcription factors driving tissue-specific expression not identified","Functional significance of IAP retroviral insertion in Ren-2 not directly proven"]},{"year":1989,"claim":"The 2.5 Å crystal structure of recombinant human renin revealed a conserved aspartyl proteinase core with variable surface loops conferring substrate specificity, enabling rational inhibitor design and explaining renin's narrow substrate selectivity for angiotensinogen.","evidence":"X-ray crystallography with molecular dynamics refinement of recombinant human renin","pmids":["2493678"],"confidence":"High","gaps":["Structure of renin bound to angiotensinogen not yet determined","Prosegment conformation and activation mechanism not resolved structurally"]},{"year":1990,"claim":"Transgenic expression of the mouse Ren-2 gene in rats caused severe hypertension despite low plasma active renin, demonstrating that extrarenal renin expression is sufficient to drive hypertension and establishing the concept of tissue-based renin-angiotensin systems.","evidence":"Transgenic rat generation (TGR(mREN2)27) with blood pressure measurement, renin activity assays, and subsequent vascular perfusion studies","pmids":["2181319","1592469"],"confidence":"High","gaps":["Relative contribution of individual tissue sites (adrenal, vascular, brain) to hypertension not dissected","Mechanism of prorenin activation in peripheral tissues unclear"]},{"year":1992,"claim":"Identification of PC1 as the specific convertase that processes prorenin to active renin in a secretory-granule-dependent manner resolved the long-standing question of how prorenin activation is compartmentalized, explaining why non-granulated cells secrete only prorenin.","evidence":"Vaccinia virus co-expression of renin with PC1, PC2, or furin in granulated (GH4) versus non-granulated (CHO, BSC-40) cells; biosynthetic labeling and immunoprecipitation","pmids":["1597471"],"confidence":"High","gaps":["Whether PC1 is the sole physiological convertase in juxtaglomerular cells in vivo not confirmed","Sorting signals directing prorenin to secretory granules not mapped"]},{"year":2001,"claim":"Discovery that Ren-1c transcription requires an Abd-B HOX·PBX·PREP1 ternary complex at a proximal promoter element identified the first transcription factor complex controlling renin gene expression, answering how cell-type-specific transcription is achieved.","evidence":"EMSA, point mutagenesis of HOX/PBX binding sites, transfection-based transcription assays, and in vivo DNA binding studies in As4.1 juxtaglomerular cells","pmids":["11432851"],"confidence":"High","gaps":["Whether this HOX·PBX·PREP1 mechanism operates at the human REN promoter not shown","Upstream signals that regulate HOX factor expression in juxtaglomerular cells unknown"]},{"year":2002,"claim":"Cloning of the (pro)renin receptor revealed that renin binding to a dedicated receptor both enhances catalytic efficiency fourfold and triggers angiotensin II–independent ERK1/2 signaling, establishing a new signaling paradigm beyond renin's classical enzymatic role.","evidence":"Expression cloning, stable transfection, binding kinetics, angiotensinogen conversion assay, and MAP kinase phosphorylation in mesangial cells; confocal co-localization","pmids":["12045255"],"confidence":"High","gaps":["Structural basis of receptor-mediated catalytic enhancement not resolved","Physiological significance of receptor signaling in vivo not established at this point"]},{"year":2003,"claim":"Mapping of the prosegment 'gate' and 'handle' regions revealed the molecular mechanism of reversible non-proteolytic prorenin activation, explaining how prorenin can gain enzymatic activity without prosegment cleavage.","evidence":"Region-specific antibody-based activation/inactivation assays at 4°C with equilibrium binding analysis; structure-guided antigen design","pmids":["12684512"],"confidence":"High","gaps":["No high-resolution structure of the prorenin-to-renin conformational transition","Whether non-proteolytic activation occurs physiologically at the (pro)renin receptor not directly shown"]},{"year":2006,"claim":"Demonstration that prorenin activates p38 MAPK/HSP27 signaling and drives actin cytoskeletal remodeling via the (pro)renin receptor, independently of angiotensin II, extended receptor signaling beyond ERK1/2 to a second major MAPK cascade with transcriptional consequences.","evidence":"p38 MAPK phosphorylation assays with SB203580 inhibitor, microarray profiling (~260 regulated genes), 2D proteomics, and immunoblotting in neonatal rat cardiomyocytes; pharmacological exclusion of AT1/AT2 and renin catalytic activity","pmids":["16940215","18212269"],"confidence":"High","gaps":["In vivo relevance of (pro)renin receptor–p38 signaling in cardiac pathology not demonstrated","Downstream transcriptional effectors mediating cytoskeletal remodeling not identified"]},{"year":2005,"claim":"Identification of biallelic REN loss-of-function mutations as a cause of autosomal recessive renal tubular dysgenesis established that renin is essential for human proximal tubular development.","evidence":"Linkage analysis and candidate gene sequencing in 9 families with 11 affected individuals showing fetal anuria and absent proximal tubular differentiation","pmids":["16116425"],"confidence":"High","gaps":["Mechanism by which angiotensin II drives tubular differentiation not elucidated","Whether renin has angiotensin-independent developmental roles not addressed"]},{"year":2009,"claim":"Discovery that dominant signal-peptide mutations in REN impair ER translocation, trigger the unfolded protein response, and cause progressive juxtaglomerular cell loss established the pathogenic mechanism of autosomal dominant tubulointerstitial kidney disease (ADTKD-REN).","evidence":"Linkage analysis, in vitro translation and ER translocation assays, ER stress marker analysis, cell growth assays, and kidney biopsy immunohistochemistry","pmids":["19664745"],"confidence":"High","gaps":["Whether ER stress is the sole mechanism or whether loss of renin secretion also contributes not fully separated","Animal model recapitulating ADTKD-REN not yet reported"]},{"year":2010,"claim":"Crystal structures of angiotensinogen alone (2.1 Å) and in complex with renin (4.4 Å) revealed that the angiotensin cleavage site is normally buried and requires a redox-sensitive conformational change for renin access, explaining why the oxidized form of angiotensinogen is the preferred substrate.","evidence":"X-ray crystallography of angiotensinogen and angiotensinogen–renin complex; redox state quantification in normal and pre-eclamptic plasma","pmids":["20927107"],"confidence":"High","gaps":["High-resolution structure of the complex not available (4.4 Å limits mechanistic detail)","Whether redox regulation of angiotensinogen is a physiological control point in vivo requires further testing"]},{"year":2020,"claim":"A large international cohort study defined three distinct ADTKD-REN subtypes based on mutation location (signal peptide, prosegment, mature renin), each with a different trafficking defect and clinical trajectory, unifying the genotype-phenotype spectrum of dominant renin mutations.","evidence":"Genotyping of 111 individuals from 30 families, cellular trafficking studies, secretion assays, signal peptide hydrophobicity analysis, survival analysis","pmids":["32750457"],"confidence":"High","gaps":["Therapeutic strategies to mitigate ER stress or restore trafficking not tested","Whether modifier genes influence ADTKD-REN progression not explored"]},{"year":null,"claim":"Key unresolved questions include the structural basis of (pro)renin receptor–mediated signaling, the in vivo physiological relevance of angiotensin II–independent (pro)renin receptor pathways, and the cell-biological mechanisms linking ER-trapped renin mutants to progressive kidney fibrosis.","evidence":"","pmids":[],"confidence":"Low","gaps":["No high-resolution structure of renin bound to the (pro)renin receptor","In vivo genetic models dissecting receptor signaling from catalytic function lacking","Mechanism of fibrosis downstream of ER stress in ADTKD-REN not defined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,9,15,29,36]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,9,29,36]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[35,38]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[11,14,15]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[28,32,33]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[31,35,38]}],"complexes":[],"partners":["AGT","ATP6AP2","PCSK1","PBX1","PREP1","HOXD10","HOXA10"],"other_free_text":[]},"mechanistic_narrative":"Renin (REN) is an aspartyl protease that catalyzes the rate-limiting cleavage of angiotensinogen to angiotensin I, initiating the renin-angiotensin cascade that controls blood pressure, renal hemodynamics, and aldosterone secretion [PMID:2493678, PMID:2181319]. Synthesized as preprorenin with a 20-residue signal peptide and 46-residue prosegment, renin undergoes signal-peptide-directed ER translocation and is converted to active renin by the convertase PC1 in a secretory-granule-dependent manner; the prosegment contains 'gate' and 'handle' regions whose displacement permits reversible non-proteolytic activation [PMID:1597471, PMID:12684512]. Renin and prorenin bind the (pro)renin receptor, which increases catalytic efficiency fourfold and triggers angiotensin II–independent ERK1/2 and p38 MAPK/HSP27 signaling cascades that remodel the actin cytoskeleton [PMID:12045255, PMID:16940215]. Dominant mutations in the signal peptide, prosegment, or mature renin domain cause autosomal dominant tubulointerstitial kidney disease (ADTKD-REN) through distinct ER-stress and trafficking defects, while biallelic loss-of-function mutations cause autosomal recessive renal tubular dysgenesis [PMID:19664745, PMID:32750457, PMID:16116425]."},"prefetch_data":{"uniprot":{"accession":"P00797","full_name":"Renin","aliases":["Angiotensinogenase"],"length_aa":406,"mass_kda":45.1,"function":"Renin is a highly specific endopeptidase, whose only known function is to generate angiotensin I from angiotensinogen in the plasma, initiating a cascade of reactions that produce an elevation of blood pressure and increased sodium retention by the kidney","subcellular_location":"Secreted; Membrane","url":"https://www.uniprot.org/uniprotkb/P00797/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/REN","classification":"Not Classified","n_dependent_lines":2,"n_total_lines":1208,"dependency_fraction":0.0016556291390728477},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/REN","total_profiled":1310},"omim":[{"mim_id":"621396","title":"SPERMATOGENESIS-ASSOCIATED SERINE-RICH PROTEIN 1; SPATS1","url":"https://www.omim.org/entry/621396"},{"mim_id":"621355","title":"KRI1 HOMOLOG; KRI1","url":"https://www.omim.org/entry/621355"},{"mim_id":"621284","title":"GA-BINDING PROTEIN TRANSCRIPTION FACTOR, SUBUNIT BETA-2; GABPB2","url":"https://www.omim.org/entry/621284"},{"mim_id":"621227","title":"OLEOYL-ACP HYDROLASE; OLAH","url":"https://www.omim.org/entry/621227"},{"mim_id":"621217","title":"BEN DOMAIN-CONTAINING PROTEIN 6; BEND6","url":"https://www.omim.org/entry/621217"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"kidney","ntpm":134.7}],"url":"https://www.proteinatlas.org/search/REN"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P00797","domains":[{"cath_id":"2.40.70.10","chopping":"31-62_75-215","consensus_level":"high","plddt":88.1402,"start":31,"end":215},{"cath_id":"2.40.70.10","chopping":"249-404","consensus_level":"high","plddt":95.1308,"start":249,"end":404}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P00797","model_url":"https://alphafold.ebi.ac.uk/files/AF-P00797-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P00797-F1-predicted_aligned_error_v6.png","plddt_mean":85.44},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=REN","jax_strain_url":"https://www.jax.org/strain/search?query=REN"},"sequence":{"accession":"P00797","fasta_url":"https://rest.uniprot.org/uniprotkb/P00797.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P00797/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P00797"}},"corpus_meta":[{"pmid":"2181319","id":"PMC_2181319","title":"Fulminant hypertension in transgenic rats harbouring the mouse Ren-2 gene.","date":"1990","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/2181319","citation_count":840,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"20081843","id":"PMC_20081843","title":"Histone deacetylase and Cullin3-REN(KCTD11) ubiquitin ligase interplay regulates Hedgehog signalling through Gli acetylation.","date":"2010","source":"Nature cell biology","url":"https://pubmed.ncbi.nlm.nih.gov/20081843","citation_count":286,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15249678","id":"PMC_15249678","title":"REN(KCTD11) is a suppressor of Hedgehog signaling and is deleted in human medulloblastoma.","date":"2004","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/15249678","citation_count":151,"is_preprint":false,"source_track":"pubmed_title"},{"pmid":"15494608","id":"PMC_15494608","title":"Abrogation of oxidative stress improves insulin sensitivity in the Ren-2 rat model of tissue angiotensin II overexpression.","date":"2004","source":"American journal of physiology. 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Cell type-specific processing of human prorenin by the convertase PC1.","date":"1992","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/1597471","citation_count":155,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"20927107","id":"PMC_20927107","title":"A redox switch in angiotensinogen modulates angiotensin release.","date":"2010","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/20927107","citation_count":155,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"12684512","id":"PMC_12684512","title":"Human prorenin has \"gate and handle\" regions for its non-proteolytic activation.","date":"2003","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/12684512","citation_count":154,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"6089171","id":"PMC_6089171","title":"Human renin gene: structure and sequence analysis.","date":"1984","source":"Proceedings of the National Academy of Sciences of the United States of America","url":"https://pubmed.ncbi.nlm.nih.gov/6089171","citation_count":147,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"26420482","id":"PMC_26420482","title":"Structural Basis for Ligand Recognition and Functional Selectivity at Angiotensin Receptor.","date":"2015","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/26420482","citation_count":146,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"16710414","id":"PMC_16710414","title":"The DNA sequence and biological annotation of human chromosome 1.","date":"2006","source":"Nature","url":"https://pubmed.ncbi.nlm.nih.gov/16710414","citation_count":144,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"15015130","id":"PMC_15015130","title":"Haplotype diversity across 100 candidate genes for inflammation, lipid metabolism, and blood pressure regulation in two populations.","date":"2004","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/15015130","citation_count":140,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"2017226","id":"PMC_2017226","title":"Renal hemodynamics and the renin-angiotensin-aldosterone system in normotensive subjects with hypertensive and normotensive parents.","date":"1991","source":"The New England journal of medicine","url":"https://pubmed.ncbi.nlm.nih.gov/2017226","citation_count":136,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"6391881","id":"PMC_6391881","title":"Primary structure of the human renin gene.","date":"1984","source":"DNA (Mary Ann Liebert, Inc.)","url":"https://pubmed.ncbi.nlm.nih.gov/6391881","citation_count":132,"is_preprint":false,"source_track":"gene2pubmed"},{"pmid":"19664745","id":"PMC_19664745","title":"Dominant renin gene mutations associated with early-onset hyperuricemia, anemia, and chronic kidney failure.","date":"2009","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19664745","citation_count":121,"is_preprint":false,"source_track":"gene2pubmed"}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":53728,"output_tokens":4408,"usd":0.113652},"stage2":{"model":"claude-opus-4-6","input_tokens":7863,"output_tokens":2937,"usd":0.16911},"total_usd":0.691725,"stage1_batch_id":"msgbatch_01SUR8NDzVrNmyszWyJeCct7","stage2_batch_id":"msgbatch_01G7Yfutko3cDWzejrwH5AMx","note":"batch pricing = 50% of standard","round2_stage1":{"model":"claude-sonnet-4-6","input_tokens":67672,"output_tokens":9988,"usd":0.176418},"round2_rules_fired":"R3","round2_stage2":{"model":"claude-opus-4-6","input_tokens":13776,"output_tokens":3446,"usd":0.232545}},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"REN (KCTD11) suppresses Hedgehog signaling by antagonizing Gli-mediated transactivation of Hedgehog target genes and by affecting Gli1 nuclear transfer, thereby inhibiting medulloblastoma cell proliferation.\",\n      \"method\": \"Loss-of-function (siRNA knockdown), overexpression in medulloblastoma cell lines, reporter assays for Gli-mediated transcription, xenograft tumor growth assays, allelic deletion analysis in human medulloblastoma\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (KD/KO, reporter assays, in vivo xenograft, nuclear localization), replicated in subsequent publications\",\n      \"pmids\": [\"15249678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"REN (KCTD11) forms an E3 ubiquitin ligase complex with Cullin3 that degrades HDAC1; HDAC1-mediated deacetylation of Gli1 and Gli2 promotes their transcriptional activation, and REN-dependent degradation of HDAC1 thereby suppresses Hedgehog signaling through a Gli acetylation checkpoint.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assays, Gli acetylation assays, HDAC activity assays, overexpression/knockdown of REN and HDAC1, mutagenesis of Gli acetylation sites, proliferation and transformation assays\",\n      \"journal\": \"Nature cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — reconstitution of E3 ligase complex, enzymatic (deacetylation) assays, mutagenesis, multiple orthogonal functional readouts in single study\",\n      \"pmids\": [\"20081843\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"REN (KCTD11) is expressed preferentially in non-proliferating inner EGL and IGL granule cells; overexpression promotes growth arrest and p27/Kip1 expression and impairs Gli2-dependent transcription and Shh-induced Gli1 mRNA expression; knockdown impairs Hedgehog antagonism and sustains GCP proliferation; REN also enhances caspase-3 activation and apoptosis in granule cell progenitors.\",\n      \"method\": \"Overexpression and siRNA knockdown in cultured granule cell progenitors, reporter assays for Gli2-dependent transcription, RT-PCR for Gli1 mRNA, TUNEL/caspase-3 assays, in situ expression analysis of EGL/IGL\",\n      \"journal\": \"The Journal of neuroscience\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (gain- and loss-of-function, transcriptional reporter, apoptosis assays), consistent with PMID 15249678 and 20081843\",\n      \"pmids\": [\"16148242\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"REN is a novel gene upregulated by neurogenic signals (retinoic acid, EGF, NGF) in pluripotent embryonal stem cells; REN overexpression induces neuronal differentiation, growth arrest, and p27Kip1 expression in CNS and PNS neural progenitor cell lines, and its inhibition impairs retinoic acid-induced neurogenin-1 and NeuroD expression.\",\n      \"method\": \"Overexpression and antisense inhibition in ES cells and neural progenitor cell lines, RT-PCR for differentiation markers (neurogenin-1, NeuroD), cell cycle/proliferation assays, developmental expression analysis by in situ hybridization\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — gain- and loss-of-function with defined molecular readouts, single lab\",\n      \"pmids\": [\"12186855\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Pathogenic REN signal peptide mutations reduce hydrophobicity required for recognition and translocation across the endoplasmic reticulum, leading to aberrant cytoplasmic delivery of preprorenin; prosegment mutations cause deposition of prorenin/renin in the ER-Golgi intermediate compartment and decreased prorenin secretion; mature renin mutations cause prorenin deposition in the ER.\",\n      \"method\": \"International cohort study with molecular analysis of 111 individuals from 30 families; subcellular localization studies of mutant prorenin (ER/ERGIC deposition); functional assay of signal peptide hydrophobicity; clinical phenotyping correlated with mutation class\",\n      \"journal\": \"Kidney international\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — large cohort with direct subcellular localization experiments, mechanistic classification by mutation domain with orthogonal biochemical evidence\",\n      \"pmids\": [\"32750457\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Introduction of the mouse Ren-2 renin gene into the rat genome causes severe hypertension despite low levels of active renin in plasma and kidney, demonstrating that extrarenal expression of renin-2 drives angiotensin-dependent hypertension.\",\n      \"method\": \"Transgenic rat generation (pronuclear injection), blood pressure measurement, tissue renin activity assays, plasma angiotensin measurement\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct transgenic model establishing causal role of Ren-2 gene in hypertension, highly replicated across labs (>800 citations)\",\n      \"pmids\": [\"2181319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"The mouse Ren-2 transgene is expressed in vascular tissue of transgenic rats and is responsible for substantially increased vascular angiotensin I and II formation; bilateral nephrectomy abolishes angiotensin release in controls but not in transgenic rats, confirming extrarenal (vascular) Ren-2 expression drives local angiotensin generation.\",\n      \"method\": \"Isolated perfused hindquarter preparation with HPLC/radioimmunoassay for angiotensin peptides, bilateral nephrectomy experiment, RNase protection assay and Northern blot for Ren-2 mRNA in mesenteric and aortic tissue\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — ex vivo perfusion reconstitution, mRNA detection in tissue, nephrectomy epistasis\",\n      \"pmids\": [\"1592469\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1985,\n      \"finding\": \"Both Ren-1 and Ren-2 loci are expressed in the kidney of two-gene mouse strains at approximately equal transcript levels, as determined by allele-specific primer extension assays.\",\n      \"method\": \"Reverse transcriptase-mediated primer extension with allele-specific dideoxynucleotide assay distinguishing Ren-1 and Ren-2 mRNAs\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct allele-specific molecular assay in tissue\",\n      \"pmids\": [\"3898081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"Ren-2 transgene expression in the adrenal gland is restricted to the X-zone rather than cycling between X-zone and zona fasciculata as in DBA/2 mice, demonstrating that adrenal cell-specific expression is controlled in trans by at least one additional locus not carried by the transgene.\",\n      \"method\": \"Transgenic mouse generation with DBA/2 Ren-2 gene in Ren-1c/Ren-1c background; tissue-specific expression analysis; genetic crosses to partially restore cycling phenotype\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — transgenic complementation with genetic cross epistasis, single lab\",\n      \"pmids\": [\"2480233\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Targeted inactivation of the Ren-2 gene in strain 129 mice results in viable, healthy mice with no blood pressure alteration, demonstrating that Ren-1d alone is sufficient to regulate normal blood pressure; loss of Ren-2 increases active renin and decreases prorenin in plasma.\",\n      \"method\": \"Gene targeting (homologous recombination) to create Ren-2-null mice; blood pressure measurement; plasma renin activity and prorenin measurement; histopathology of renin-expressing tissues\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — gene knockout with direct blood pressure phenotyping and biochemical characterization\",\n      \"pmids\": [\"8952610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1984,\n      \"finding\": \"Ren-1 and Ren-2 genes have strongly conserved promoter sequences near the transcription start site, but diverge approximately 150 bp upstream; tissue-specific utilization of homologous transcription start sites is the critical determinant of their differential expression patterns.\",\n      \"method\": \"Genomic sequence analysis; S1 nuclease protection assay of submaxillary gland and kidney RNAs to map transcription initiation sites\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct S1 mapping of transcription start sites plus sequence analysis, single lab\",\n      \"pmids\": [\"6392850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Expression from the mouse Ren-1c renin gene requires an Abd-B class HOX.PBX recognition sequence (TAATAAATCAA) at the proximal promoter element (~-60); HOXD10 binds this element with high affinity and forms a ternary complex with PBX1b and PREP1; point mutations in either HOX or PBX half-site disrupt complex formation and dramatically decrease Ren-1c transcriptional activity.\",\n      \"method\": \"EMSA, in vitro binding assays with purified HOX/PBX proteins, in vivo chromatin immunoprecipitation equivalent (ternary complex assay), site-directed mutagenesis of PPE, transient transfection reporter assays in As4.1 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro binding reconstitution, mutagenesis, and functional reporter assays in renin-expressing cells\",\n      \"pmids\": [\"11432851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Mice lacking functional Ren-1d exhibit complete absence of juxtaglomerular cell granulation and atypical macula densa morphology; a BAC transgene containing Ren-1d restores normal renal structure; renin-2 overexpression cannot compensate for loss of renin-1d, indicating primary structural differences between the isoforms underlie the granulation difference.\",\n      \"method\": \"BAC transgenesis, homologous recombination in E. coli to insert IRES-beta-geo into Ren-1d, backcross complementation onto Ren-1d-null background, histopathology and beta-galactosidase reporter expression\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genetic complementation with BAC transgenesis and loss-of-function, direct morphological phenotype\",\n      \"pmids\": [\"10995772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"The Ren-1d and Ren-1c alleles of the mouse Ren-1 gene exhibit characteristic, allele-specific expression patterns in adrenal gland, testis, and sex accessory tissues, regulated by sequences in cis closely associated with each allele.\",\n      \"method\": \"Allele-specific dideoxynucleotide primer extension assay on tissue RNAs; genetic analysis of mice with one vs. two renin loci\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct allele-specific molecular assay, genetic analysis, single lab\",\n      \"pmids\": [\"2677011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Mouse Ren-2 prorenin expressed in CHO cells has a molecular mass of 42 kDa and isoelectric point of 6.5; amino-terminal sequencing confirmed the predicted prosegment cleavage site from the nucleotide sequence of Ren-2 preprorenin cDNA.\",\n      \"method\": \"CHO cell expression of Ren-2 preprorenin, protein purification by ion exchange and isoelectric focusing chromatography, SDS-PAGE, N-terminal sequencing\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct biochemical characterization of purified recombinant prorenin protein\",\n      \"pmids\": [\"2202716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Renin-expressing cells in the brain, identified using an REN-eGFP transgenic mouse model, are predominantly neuronal and located in specific cardiovascular-control regions including cerebellum, hippocampus, rostral ventrolateral medulla, paraventricular nucleus-associated areas, and subfornical organ.\",\n      \"method\": \"Transgenic mice expressing eGFP under mouse renin promoter; brain region identification by co-labeling with neuron-specific (NeuN) and glia-specific antisera; fluorescence microscopy\",\n      \"journal\": \"Physiological genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct live-imaging/fluorescence localization with cell-type co-labeling in transgenic model\",\n      \"pmids\": [\"14625376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"High adrenal renin activity in TGR(mREN2)27 transgenic rats elevates adrenocortical steroid production and impairs aldosterone regulation, demonstrating the functional role of the local adrenal renin-angiotensin system in vivo.\",\n      \"method\": \"In vivo studies in Ren-2 transgenic rats; measurement of adrenal renin activity, plasma and adrenal angiotensin II, plasma aldosterone; comparison to kidney/plasma renin-suppressed background\",\n      \"journal\": \"Hormone and metabolic research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo transgenic model with defined biochemical endpoints, single lab\",\n      \"pmids\": [\"9694562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"The Ren-1 and Ren-2 mouse renin gene loci are physically linked on chromosome 1, with Ren-2 upstream of Ren-1 and the coding sequences separated by approximately 20 kb, as determined by pulsed-field gel electrophoresis mapping.\",\n      \"method\": \"Pulsed-field gel electrophoresis (PFGE) restriction mapping of DBA/2 genomic DNA\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct physical mapping by PFGE\",\n      \"pmids\": [\"2833727\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"REN (KCTD11) is a tumor suppressor and Hedgehog pathway inhibitor that forms a Cullin3 E3 ubiquitin ligase complex to degrade HDAC1, thereby promoting Gli1/Gli2 acetylation and suppressing their transcriptional activity; it also blocks Gli1 nuclear translocation, promotes neuronal differentiation and apoptosis in granule cell progenitors, and is frequently deleted in medulloblastoma. The REN gene (encoding renin) encodes a protease whose signal peptide, prosegment, and mature peptide each have distinct roles in prorenin processing, ER translocation, and secretion, and whose expression—including extrarenal and intrarenal sites—is controlled by Abd-B class HOX.PBX transcription factor complexes and is regulated in a tissue- and allele-specific manner via cis-acting promoter elements.\"\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\nI'll classify each paper and extract discoveries only from KEEP papers.\n\n**Classification notes:**\n- Papers about mouse Ren-1/Ren-2 (renin genes) → KEEP (orthologs/direct models of human REN)\n- Papers about KCTD11/REN (tumor suppressor in medulloblastoma) → EXCLUDE (different gene, alias collision - REN here = KCTD11)\n- Papers about Lactobacillus salivarius REN → EXCLUDE (bacterial strain name)\n- Papers about Streptomyces REN-7/REN-21 → EXCLUDE (microbial strain name)\n- Papers about λ phage ren gene → EXCLUDE (phage gene)\n- Papers about ReN 1869 (drug) → EXCLUDE\n- Papers about ReN cells (mesothelioma cell line) → EXCLUDE\n- Papers about \"ren\" in Chinese medicine names (Ren-shen, Suan-Zao-Ren, Zao-Ren) → EXCLUDE\n- Papers about NY-REN-21 → EXCLUDE (different protein)\n- Papers about Ren(ari) cotton nematode resistance → EXCLUDE (plant gene)\n- Papers about ReN8 (rhenium compound) → EXCLUDE\n- Human REN gene (renin) papers → KEEP\n\n```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1983,\n      \"finding\": \"The primary structure of human renin precursor was deduced from cDNA sequencing, revealing a 406-amino acid preprorenin with a 20-amino acid pre-segment and 46-amino acid pro-segment, with high sequence homology to mouse renin and structural similarity to aspartyl proteinases.\",\n      \"method\": \"cDNA library screening, nucleotide sequencing, sequence homology analysis\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct cDNA sequencing with full structural characterization; foundational paper (285 citations)\",\n      \"pmids\": [\"6324167\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1984,\n      \"finding\": \"The human renin gene spans ~12 kb of DNA, contains 9 exons (encoding a 403-amino acid preprorenin) interrupted by 8 introns, with a TATA box promoter and glucocorticoid-response-like elements ~200–300 bp upstream; its structure is evolutionarily related to pepsinogen, and there is a single copy in the human genome.\",\n      \"method\": \"Genomic DNA cloning, restriction mapping, DNA sequencing, hybridization with mouse renin cDNA and synthetic oligonucleotide probes\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — complete gene structure determined by sequencing; replicated by independent group (Hardman et al. same year)\",\n      \"pmids\": [\"6089171\", \"6391881\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1984,\n      \"finding\": \"Mouse Ren-1 and Ren-2 genes exhibit markedly different tissue-specific expression patterns despite conserved proximal promoter elements; a repetitive DNA element (IAP retroviral provirus) and sequence differences ~150 bp upstream of the transcription start site distinguish the Ren-2 copy, and tissue-specific utilization of homologous transcription start sites underlies their differential expression.\",\n      \"method\": \"Genomic sequencing, S1 nuclease analysis, comparative 5'-flanking region analysis, Northern blot\",\n      \"journal\": \"Molecular and cellular biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct sequencing and functional mapping of transcription initiation; foundational mechanistic study\",\n      \"pmids\": [\"6392850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1984,\n      \"finding\": \"A complete intra-cisternal A particle (IAP) retroviral genome (MIARN) was identified within the Ren-2 locus of DBA/2 mice, flanking the 5' LTR with a phenylalanine tRNA-complementary sequence required for minus-strand synthesis initiation; this retroviral association may contribute to the high expression of Ren-2.\",\n      \"method\": \"Complete nucleotide sequencing of IAP genome, structural analysis of LTRs and tRNA binding site\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — complete sequence; mechanistic link to Ren-2 expression is inferred rather than directly demonstrated\",\n      \"pmids\": [\"6095203\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1985,\n      \"finding\": \"Both Ren-1 and Ren-2 loci are expressed in the kidney of two-gene mouse strains at approximately equal mRNA levels, demonstrated using reverse transcriptase-mediated primer extension assays exploiting base sequence differences between the two highly homologous transcripts.\",\n      \"method\": \"Reverse transcriptase-mediated primer extension with dideoxynucleotide discrimination, oligonucleotide primer-based allele-specific assay\",\n      \"journal\": \"Proceedings of the National Academy of Sciences of the United States of America\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct allele-specific quantification with two orthogonal methods\",\n      \"pmids\": [\"3898081\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1988,\n      \"finding\": \"Physical mapping by pulsed-field gel electrophoresis revealed that mouse Ren-1 and Ren-2 are separated by ~20 kb of DNA, transcribed in the same orientation, with Ren-2 upstream of Ren-1, within a ~120 kb genomic region on chromosome 1.\",\n      \"method\": \"Pulsed-field gel electrophoresis, restriction mapping\",\n      \"journal\": \"Nucleic acids research\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct physical mapping with PFGE\",\n      \"pmids\": [\"2833727\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"The complete nucleotide sequence of mouse Ren-1d was determined; all three renin genes (Ren-1c, Ren-1d, Ren-2d) span ~9.6 kb with 9 exons and 8 introns, with significant sequence differences in their 5'-flanking regions that likely underlie differential regulation.\",\n      \"method\": \"Complete genomic DNA sequencing, comparative sequence analysis of 5'-flanking regions\",\n      \"journal\": \"Gene\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — complete gene sequence with comparative structural analysis\",\n      \"pmids\": [\"2691339\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"Expression of the DBA/2J Ren-2 transgene in mice was restricted to the X-zone of the adrenal gland (rather than cycling between X-zone and zona fasciculata as in native DBA/2 mice), demonstrating that cell-specific adrenal expression of Ren-2 is mediated in trans by at least one additional locus not present in the host genome.\",\n      \"method\": \"Transgenic mouse generation, tissue expression analysis, hormonal control experiments, genetic crosses\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — transgenic complementation with genetic crosses revealing trans-regulation\",\n      \"pmids\": [\"2480233\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"The two Ren-1 alleles (Ren-1c and Ren-1d) exhibit characteristic, allele-specific expression patterns in adrenal gland, testis, and sex accessory gland tissue that are regulated by closely associated cis-acting sequences, as demonstrated by allele-specific dideoxynucleotide primer extension assays and genetic analysis.\",\n      \"method\": \"Allele-specific dideoxynucleotide primer extension assay, genetic analysis of one- vs two-gene mouse strains\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — allele-specific assay with genetic epistasis analysis across multiple tissues\",\n      \"pmids\": [\"2677011\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1989,\n      \"finding\": \"The crystal structure of recombinant human renin was determined at 2.5 Å resolution, revealing that renin is an aspartyl proteinase with a highly conserved structural core and active site compared to other aspartyl proteinases, but with variable surface loops that confer substrate specificity; this structural knowledge enabled rational inhibitor design.\",\n      \"method\": \"X-ray crystallography with molecular dynamics refinement\",\n      \"journal\": \"Science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structure at 2.5 Å with functional implications; 191 citations\",\n      \"pmids\": [\"2493678\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Introduction of the mouse Ren-2 renin gene into the rat genome caused severe fulminant hypertension without overexpression of active renin in the kidney or elevated plasma active renin, establishing that extrarenal expression of a renin gene is sufficient to cause severe hypertension and providing a model of low-renin hypertension.\",\n      \"method\": \"Transgenic rat generation, blood pressure measurement, renin activity assays\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — transgenic gain-of-function with defined genetic lesion; 840 citations, replicated by multiple groups\",\n      \"pmids\": [\"2181319\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1990,\n      \"finding\": \"Mouse Ren-2 prorenin (42 kDa, pI 6.5) was purified from transfected Chinese hamster ovary cells; amino-terminal sequencing confirmed the predicted prorenin sequence from the Ren-2 preprorenin cDNA, establishing that CHO cells secrete the correctly processed prorenin form.\",\n      \"method\": \"CHO cell transfection, multi-step chromatographic purification (DEAE-Toyopearl, Blue-Toyopearl, isoelectric focusing), SDS-PAGE, amino-terminal sequencing\",\n      \"journal\": \"Journal of biochemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — protein purification with biochemical characterization and sequence validation\",\n      \"pmids\": [\"2202716\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1991,\n      \"finding\": \"Substrate (angiotensinogen) paucity in Mus, consistent with first-order kinetics, phenotypically inhibits the renin-angiotensin system and was a prerequisite for the evolutionary emergence of enhanced Ren-2 expression in the submandibular gland; intravenous angiotensinogen injection markedly raised blood pressure, demonstrating that substrate limitation normally constrains renin activity.\",\n      \"method\": \"Comparative physiological experiments, intravenous substrate injection, blood pressure measurement across Mus strains\",\n      \"journal\": \"General and comparative endocrinology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo functional demonstration of substrate limitation; single study\",\n      \"pmids\": [\"1916217\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"The mouse Ren-2 transgene is expressed in vascular (mesenteric and aortic) tissue of transgenic rats, leading to substantially increased vascular angiotensin I and II formation (measured by HPLC and RIA from perfused hindquarters); bilateral nephrectomy abolished angiotensin release in controls but not transgenic rats, establishing that vascular Ren-2 expression drives local angiotensin formation independent of kidney renin.\",\n      \"method\": \"Isolated perfused hindquarter preparation, HPLC, radioimmunoassay, RNase protection assay, Northern blot, bilateral nephrectomy\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods (perfusion, RIA, RNase protection, Northern, nephrectomy) in same study\",\n      \"pmids\": [\"1592469\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"Prorenin is markedly elevated in plasma of Ren-2 transgenic rats despite suppressed active renin and angiotensin levels; hypertension is driven by angiotensin II and is extremely sensitive to ACE inhibitor (captopril) treatment, and sodium depletion normalizes blood pressure, implicating a volume-dependent/adrenal renin-angiotensin component.\",\n      \"method\": \"Transgenic rat model, blood pressure monitoring, ACE inhibitor treatment, sodium depletion protocol, prorenin/renin assays\",\n      \"journal\": \"Kidney international. Supplement\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological dissection in transgenic model; single study\",\n      \"pmids\": [\"1630068\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1992,\n      \"finding\": \"Prorenin is converted to active renin by the convertase PC1 in a cell-type-specific manner requiring secretory granules (demonstrated in GH4 somatomammotroph cells), but not by PC2 or furin, and not in cells lacking granules (CHO, BSC-40 cells); this establishes the intracellular compartment as a critical determinant of prorenin processing.\",\n      \"method\": \"Vaccinia virus expression system, biosynthetic labeling, cell-type comparison (GH4 vs CHO/BSC-40), immunoprecipitation\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution-type experiment with multiple cell lines and convertases; 155 citations\",\n      \"pmids\": [\"1597471\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"Renin mRNA is expressed in multiple human tissues (kidney, adrenal gland, placenta, saphenous vein) as quantified by competitive PCR using a deletion-mutant internal standard; kidney has the highest renin mRNA concentration, followed by adrenal, placenta, and vein.\",\n      \"method\": \"Reverse transcription-PCR, competitive quantitative PCR with internal deletion-mutant standard\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — quantitative PCR with rigorous internal standard; 224 citations\",\n      \"pmids\": [\"8387539\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1993,\n      \"finding\": \"The Ren-2 transgene in TGR(mREN2)27 rats is expressed in cardiovascular-regulatory organs (adrenal, kidney, brain) before hypertension develops; hypertension is associated with decreased plasma angiotensin I and near-undetectable angiotensin-(1-7), and is mediated by the renin-angiotensin system since ACE inhibition and AT1 blockade normalize blood pressure, with nitric oxide contributing more in transgenic than normotensive rats.\",\n      \"method\": \"Transgenic rat model, plasma angiotensin peptide measurement, lisinopril/losartan pharmacological intervention, L-NMMA injection, RNase protection assay\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — pharmacological dissection with multiple interventions; replicated across multiple papers\",\n      \"pmids\": [\"8238495\", \"8184972\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"In Ren-2 transgenic hypertensive rats, central (intracerebroventricular) administration of angiotensin II or angiotensin-(1-7) increases local vasopressin (AVP) release from paraventricular and supraoptic nuclei in control but not transgenic rats, demonstrating that insertion of the mouse renin gene alters the brain angiotensin-vasopressin axis; transgenic rats showed 22-fold higher AVP in the dorsal lower brain stem.\",\n      \"method\": \"Brain microdialysis, intracerebroventricular infusion, radioimmunoassay of AVP and angiotensin peptides\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct microdialysis measurement with pharmacological challenge; single study\",\n      \"pmids\": [\"8092324\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"In Ren-2 transgenic rat coronary arteries, hypertension selectively abolishes endothelium-dependent contractions in response to L-NAME (NOS inhibition), while endothelium-dependent relaxations to acetylcholine and smooth muscle function remain intact, indicating a selective impairment of EDNO-dependent contractile tone.\",\n      \"method\": \"Isolated coronary artery myograph/organ chamber preparation, isometric tension recording, pharmacological dissection with L-NAME, SQ30741\",\n      \"journal\": \"Circulation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ex vivo vascular preparation with pharmacological dissection; single study\",\n      \"pmids\": [\"8205692\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1995,\n      \"finding\": \"Tubuloglomerular feedback (TGF) responses in Ren-2 transgenic hypertensive rats are enhanced and ~84% dependent on angiotensin II acting via AT1 receptors (blocked by L-158,809), with only ~43% of the attenuation attributable to blood pressure reduction alone, establishing a direct role for locally generated angiotensin II in sensitizing the TGF mechanism.\",\n      \"method\": \"Stop-flow pressure micropuncture, AT1 receptor antagonist administration, mechanical renal arterial pressure reduction\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo micropuncture with pharmacological and mechanical dissection; single study\",\n      \"pmids\": [\"7771510\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1996,\n      \"finding\": \"Targeted inactivation of the mouse Ren-2 gene showed that mice lacking Ren-2 are viable and normotensive, with increased active renin and decreased prorenin in plasma; the Ren-1d gene alone is sufficient to regulate normal blood pressure, demonstrating that Ren-2 is functionally redundant for blood pressure control despite differing tissue expression.\",\n      \"method\": \"Gene targeting/knockout, blood pressure measurement, plasma renin and prorenin quantification, histopathological analysis\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — definitive loss-of-function with phenotypic characterization; clean genetic experiment\",\n      \"pmids\": [\"8952610\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"In female Ren-2 transgenic rats, adrenal angiotensin II is significantly elevated compared to controls, while kidney angiotensin II is unchanged but angiotensin I and angiotensin-(1-7) are lower; cardiac angiotensin I, II, and angiotensin-(2-10) are reduced while angiotensin-(2-7) is increased. Tissue angiotensins cycle with estrous stage in both strains, establishing organ-specific angiotensin II generation patterns driven by the Ren-2 transgene.\",\n      \"method\": \"HPLC, radioimmunoassay of multiple angiotensin peptides from adrenal, kidney, and heart tissue\",\n      \"journal\": \"Peptides\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — HPLC + RIA with multiple peptide measurements; single study\",\n      \"pmids\": [\"9880073\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"Concomitant with elevated adrenal renin activity in TGR(mREN2)27 rats, adrenocortical steroid production is elevated and aldosterone regulation is impaired; since kidney and plasma renin and angiotensins are low, these findings establish a functional role for the local adrenal renin-angiotensin system (driven by Ren-2) in controlling aldosterone production.\",\n      \"method\": \"Adrenal renin activity measurement, steroid and aldosterone assays, comparison with plasma/kidney renin levels in transgenic vs control rats\",\n      \"journal\": \"Hormone and metabolic research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — functional endocrine measurements in transgenic model with appropriate controls; single study\",\n      \"pmids\": [\"9694562\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"AT1 receptor binding is significantly increased in glomeruli, proximal tubules, and inner stripe of outer medulla of Ren-2 transgenic hypertensive rats (but not AT2 receptors), mainly in vascular smooth muscle of intrarenal vessels, juxtaglomerular apparatus, mesangial cells, and proximal tubular cells; AT1 blockade with losartan markedly reduced mean arterial pressure and increased renal blood flow in transgenic but not control rats, establishing that upregulated intrarenal AT1 receptors mediate the renal hemodynamic effects of elevated angiotensin II.\",\n      \"method\": \"In vitro autoradiography of renal AT1/AT2 receptors, immunohistochemistry, renal hemodynamics measurement, AT1/AT2 receptor blockade\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — receptor mapping with multiple methods (autoradiography, IHC, pharmacology) in vivo and ex vivo\",\n      \"pmids\": [\"9931128\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Ren-2 hypertensive transgenic rats exhibit exaggerated renal vascular responsiveness specifically to angiotensin II (but not to norepinephrine or vasodilators), with intrarenal angiotensin II causing larger decreases in renal blood flow than in normotensive controls, establishing a selective enhancement of angiotensin II-mediated renal vasoconstriction.\",\n      \"method\": \"Intravenous and intrarenal arterial angiotensin II administration, renal blood flow measurement, pharmacological comparison with norepinephrine, bradykinin, and acetylcholine\",\n      \"journal\": \"The American journal of physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo pharmacological dose-response; selectivity demonstrated by comparison with other vasoconstrictors\",\n      \"pmids\": [\"9950963\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"BAC transgenesis of a 145 kb region encompassing both Ren-1d and Ren-2 loci completely rescued juxtaglomerular cell granulation and macula densa morphology in Ren-1d-null mice; homologous recombination inserting an IRES-β-geo marker into Ren-1d confirmed that juxtaglomerular cells express Ren-1d throughout development even without granulation, and that Ren-2 overexpression cannot functionally compensate for loss of Ren-1d, establishing primary structural differences between the two isoforms as responsible for differential granulation.\",\n      \"method\": \"BAC transgenesis, homologous recombination in E. coli (piggy-BAC), backcross genetic complementation, lacZ reporter expression, histological analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — genetic complementation with reporter insertion and null background; multiple orthogonal approaches\",\n      \"pmids\": [\"10995772\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Expression from the mouse Ren-1c gene requires a proximal promoter element (PPE at ~-60) that is an Abd-B class HOX·PBX binding consensus sequence (TAATAAATCAA); Abd-B HOX members (HOXD10, HOXA10, HOXA9, HOXB9, HOXC9) bind this element with or without PBX1b, and point mutations in either the HOX or PBX half-site dramatically decreased Ren-1c transcriptional activity; PBX1b, PREP1, and HOX form a ternary complex on the PPE both in vivo and in vitro.\",\n      \"method\": \"Electrophoretic mobility shift assay, in vitro binding assays, point mutagenesis, transfection-based transcriptional activity assays, in vivo DNA binding studies in As4.1 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct mutagenesis of binding sites with functional readout; reconstituted ternary complex in vitro and in vivo\",\n      \"pmids\": [\"11432851\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"Renin and prorenin binding to the cloned (pro)renin receptor (a 350-amino acid single transmembrane domain protein) increases the catalytic efficiency of angiotensin I generation from angiotensinogen fourfold and induces intracellular signaling (phosphorylation of serine/tyrosine residues and ERK1/2 activation) independently of angiotensin II; the receptor is localized by confocal microscopy to glomerular mesangium and subendothelium of coronary and kidney arteries, co-localizing with renin.\",\n      \"method\": \"Expression cloning, stable transfection, specific binding assay, angiotensinogen conversion kinetics, MAP kinase phosphorylation assay, confocal microscopy\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstituted receptor binding with enzymatic kinetics + signaling assays + localization; 1101 citations\",\n      \"pmids\": [\"12045255\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Human prorenin has a 'gate' region (T7PFKR10P) and 'handle' region (I11PFLKR15P) in the prosegment that are critical for its non-proteolytic activation; antibodies targeting the handle region (anti-11/26) non-proteolytically activate 90% of prorenin at 4°C, and acid-activated prorenin exposes both regions for antibody binding; handle- and gate-region antibodies prevent re-inactivation, defining the molecular mechanism of reversible prorenin activation.\",\n      \"method\": \"Antibody-based non-proteolytic activation assay, acid-activation/re-inactivation experiments, equilibrium dissociation constant determination, tertiary structure-guided antigen design\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — mechanistic dissection with five region-specific antibodies; reconstituted activation/inactivation cycle; 154 citations\",\n      \"pmids\": [\"12684512\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2004,\n      \"finding\": \"Renin-expressing cells in the brain were identified using an eGFP reporter transgene driven by the mouse renin promoter; eGFP-positive cells were found in cerebellum, hippocampus, dorsal motor nucleus of the vagus, inferior olivary nucleus, reticular formation, rostral ventrolateral medulla, central nucleus of the amygdala, lateral parabrachial nucleus, mesencephalic trigeminal nucleus, bed nucleus of stria terminalis, and subfornical organ; co-labeling confirmed these cells are predominantly neuronal.\",\n      \"method\": \"eGFP reporter transgenic mouse, fluorescence microscopy, co-immunolabeling with neuron- and glia-specific antisera\",\n      \"journal\": \"Physiological genomics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — direct reporter-based localization with cell-type co-labeling; identifies specific brain nuclei\",\n      \"pmids\": [\"14625376\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2005,\n      \"finding\": \"Loss-of-function mutations in renin (REN), angiotensinogen, ACE, or angiotensin II type 1 receptor cause autosomal recessive renal tubular dysgenesis, characterized by fetal anuria and absence of differentiated proximal tubules; this establishes that REN activity and the renin-angiotensin system are essential for human renal tubular development.\",\n      \"method\": \"Linkage analysis, candidate gene sequencing, homozygosity/compound heterozygosity mapping in 9 families with 11 affected individuals\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — human genetic loss-of-function with defined molecular lesion across multiple families; 182 citations\",\n      \"pmids\": [\"16116425\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Prorenin and renin binding to the (pro)renin receptor in human monocytes (U937 cells) induces long-lasting ERK1/2 phosphorylation independently of angiotensin II (persisting with AT1 and AT2 receptor blockade), via MEK1/2-dependent signaling; this signaling is distinct from angiotensin II-ERK signaling (not involving EGF receptor transactivation). Aliskiren (direct renin inhibitor) does not block (pro)renin receptor binding or ERK1/2 activation.\",\n      \"method\": \"Immunoprecipitation, Western blot for phospho-ERK1/2, receptor binding with 125I-labeled renin/prorenin, AT1/AT2 blockade, MEK inhibitor, FACS analysis\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — multiple orthogonal methods; receptor binding + signaling pathway dissection with pharmacological controls; 186 citations\",\n      \"pmids\": [\"18212269\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Prorenin activates p38 MAPK and phosphorylates HSP27 in neonatal rat cardiomyocytes through the (pro)renin receptor, independently of angiotensin II (not blocked by aliskiren or AT1 antagonist eprosartan); this leads to transcriptional regulation of ~260 genes including those involved in actin filament dynamics and results in actin cytoskeleton remodeling.\",\n      \"method\": \"p38 MAPK phosphorylation assay, SB203580 (p38 inhibitor) blocking experiment, microarray gene expression profiling (4800 genes), quantitative RT-PCR, 2D proteomics, immunoblotting\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — mechanistic pathway (p38/HSP27) with inhibitor blocking, microarray, proteomics; 198 citations\",\n      \"pmids\": [\"16940215\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2007,\n      \"finding\": \"ACE2 is the primary enzyme responsible for cardiac angiotensin-(1-7) generation from angiotensin II in hypertrophic hearts of Ren-2 hypertensive rats; ACE2 inhibition (MLN-4760) reduced cardiac angiotensin-(1-7) production by 83% in hypertensive but had no significant effect in normotensive hearts, demonstrating a compensatory upregulation of cardiac ACE2 in hypertension.\",\n      \"method\": \"Langendorff isolated heart preparation, HPLC-RIA angiotensin peptide measurement, pharmacological ACE2 inhibition, ACE2 activity assay, Western blot for ACE2 protein\",\n      \"journal\": \"American journal of physiology. Heart and circulatory physiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — ex vivo organ preparation with pharmacological inhibition and protein quantification\",\n      \"pmids\": [\"17308000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"Dominant mutations in the signal sequence of human renin (p.Leu16del, p.Leu16Arg) reduce signal peptide hydrophobicity, impair ER translocation and processing of preprorenin, resulting in reduced or abolished prorenin/renin biosynthesis and secretion; cells expressing p.Leu16del show activated ER stress, unfolded protein response, and reduced growth rate, causing progressive juxtaglomerular cell loss and autosomal dominant kidney disease.\",\n      \"method\": \"Linkage analysis, candidate gene sequencing, transfection studies, in vitro translation, ER translocation assay, ER stress markers (Western blot), cell growth assay, kidney biopsy immunohistochemistry\",\n      \"journal\": \"American journal of human genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstituted ER translocation defect with in vitro and cell-based validation + human genetic evidence; 121 citations\",\n      \"pmids\": [\"19664745\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"The crystal structure of human angiotensinogen at 2.1 Å reveals that the angiotensin cleavage site is inaccessibly buried in its amino-terminal tail; a 4.4 Å structure of the angiotensinogen-renin complex reveals the conformational rearrangement (linked by a conserved disulphide bridge) required for renin to access and cleave the substrate. The oxidized (sulphydryl-bridged) form of angiotensinogen preferentially interacts with receptor-bound renin, and the reduced:oxidized ratio is ~40:60 in circulation, rising in pre-eclampsia.\",\n      \"method\": \"X-ray crystallography (2.1 Å angiotensinogen alone; 4.4 Å complex with renin), redox state analysis of circulating angiotensinogen, pre-eclampsia patient samples\",\n      \"journal\": \"Nature\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — crystal structures of substrate alone and in complex with renin, revealing mechanism of substrate recognition; 155 citations\",\n      \"pmids\": [\"20927107\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"miR-663 and miR-181a bind to the 3'-UTR of the REN mRNA and regulate renin mRNA levels in human kidney (HEK293) cells, as demonstrated by luciferase reporter gene experiments; in hypertensive human kidneys, two miRNAs are downregulated, potentially explaining elevated intrarenal renin mRNA.\",\n      \"method\": \"Microarray transcriptomics, quantitative RT-PCR validation, luciferase reporter assay with REN 3'-UTR in HEK293 cells, miRNA transfection\",\n      \"journal\": \"Hypertension\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct 3'-UTR luciferase reporter assay with miRNA transfection; single study in cell line\",\n      \"pmids\": [\"22042811\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"An international cohort study of 111 individuals from 30 families with ADTKD-REN defined three pathophysiologically distinct subtypes based on mutation location: (1) signal peptide mutations reduce hydrophobicity required for ER recognition/translocation, leading to aberrant cytoplasmic delivery of preprorenin; (2) prosegment mutations cause prorenin/renin deposition in the ER-Golgi intermediate compartment with decreased secretion; (3) mature renin mutations cause mutant prorenin deposition in the ER (similar to ADTKD-UMOD), with slowest progression to end-stage kidney disease.\",\n      \"method\": \"International cohort clinical study, genotyping of 30 families, signal peptide hydrophobicity analysis, cellular trafficking studies (ER-Golgi localization), secretion assays, survival analysis\",\n      \"journal\": \"Kidney international\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — large multi-family cohort with mechanistic cellular studies; three distinct mechanisms validated\",\n      \"pmids\": [\"32750457\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"Human renin (REN) is an aspartyl protease whose crystal structure (2.5 Å) reveals a conserved catalytic core with variable surface loops conferring specificity; it is synthesized as preprorenin (signal peptide + 46-aa prosegment required for ER translocation), processed to prorenin in the secretory pathway by the convertase PC1 in a secretory granule-dependent manner, and can be non-proteolytically activated by displacement of the prosegment 'gate' and 'handle' regions; active renin cleaves angiotensinogen (whose angiotensin site is normally buried but exposed upon conformational change linked to a redox-responsive disulphide bridge) to generate angiotensin I; renin and prorenin also bind the (pro)renin receptor, which increases catalytic efficiency fourfold and triggers angiotensin II-independent ERK1/2 and p38 MAPK/HSP27 signaling; transcription of Ren-1c requires Abd-B HOX·PBX·PREP1 ternary complexes at a proximal promoter element; renin mRNA is regulated post-transcriptionally by miR-663 and miR-181a; dominant signal-peptide mutations cause ER translocation failure and ER stress leading to ADTKD, while prosegment mutations trap prorenin in the ER-Golgi compartment, and mature-renin mutations deposit mutant protein in the ER.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"REN encodes renin, an aspartyl protease that catalyzes the rate-limiting cleavage of angiotensinogen to angiotensin I, initiating the renin-angiotensin cascade that controls blood pressure and fluid homeostasis. In the mouse, the duplicated Ren-1 and Ren-2 loci are physically linked on chromosome 1 and exhibit allele-specific, tissue-specific expression patterns controlled by cis-regulatory elements and an Abd-B class HOX·PBX·PREP1 transcription factor complex at the proximal promoter [PMID:2833727, PMID:2677011, PMID:11432851]. Pathogenic mutations in distinct domains of human REN—signal peptide, prosegment, and mature peptide—differentially impair ER translocation, prorenin trafficking through the ER–Golgi intermediate compartment, and secretion, establishing genotype–phenotype correlations in REN-associated kidney disease [PMID:32750457]. Transgenic and knockout studies demonstrate that extrarenal renin expression in vascular and adrenal tissue generates local angiotensin II sufficient to drive hypertension independently of renal renin, while Ren-1d is uniquely required for juxtaglomerular cell granulation [PMID:2181319, PMID:10995772].\",\n  \"teleology\": [\n    {\n      \"year\": 1984,\n      \"claim\": \"Determining how the duplicated Ren-1 and Ren-2 genes achieve differential tissue expression revealed that conserved proximal promoters diverge ~150 bp upstream and use homologous but tissue-specific transcription start sites, establishing cis-regulatory divergence as the basis for expression differences.\",\n      \"evidence\": \"S1 nuclease protection mapping of submaxillary and kidney RNAs plus genomic sequence comparison\",\n      \"pmids\": [\"6392850\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Specific transcription factors binding the divergent upstream region were unknown\", \"Functional validation of promoter elements by deletion/reporter not performed\"]\n    },\n    {\n      \"year\": 1985,\n      \"claim\": \"Whether both renin loci contribute equally to kidney expression was answered by allele-specific primer extension showing Ren-1 and Ren-2 transcripts at approximately equal levels in kidney of two-gene strains.\",\n      \"evidence\": \"Allele-specific dideoxynucleotide primer extension on kidney RNA\",\n      \"pmids\": [\"3898081\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Protein-level contributions of each locus not measured\", \"Regulation under physiological perturbation (salt, volume depletion) not assessed\"]\n    },\n    {\n      \"year\": 1988,\n      \"claim\": \"The physical arrangement of the two renin loci was resolved: Ren-2 lies upstream of Ren-1 with ~20 kb separating their coding regions on chromosome 1, establishing the tandem duplication architecture.\",\n      \"evidence\": \"Pulsed-field gel electrophoresis mapping of DBA/2 genomic DNA\",\n      \"pmids\": [\"2833727\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether shared or independent enhancers lie in the intergenic region was not determined\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"Allele-specific expression patterns in adrenal, testis, and sex-accessory tissues of Ren-1d vs. Ren-1c alleles were shown to be controlled in cis, and Ren-2 adrenal expression was found to require at least one additional trans-acting locus not carried by the transgene.\",\n      \"evidence\": \"Allele-specific primer extension across congenic/transgenic lines; transgenic Ren-2 expression restricted to X-zone in non-native background, partially restored by genetic crosses\",\n      \"pmids\": [\"2677011\", \"2480233\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the trans-acting locus controlling adrenal cycling expression was not determined\", \"Single-lab findings for the trans-acting locus\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Whether extrarenal renin expression can drive hypertension was answered by introducing the Ren-2 transgene into rats: severe angiotensin-dependent hypertension resulted despite low renal and plasma active renin, proving that extrarenal renin is functionally sufficient to elevate blood pressure.\",\n      \"evidence\": \"Transgenic rat (TGR(mREN2)27) with blood pressure measurement, tissue renin assays, plasma angiotensin measurement; subsequent vascular perfusion and nephrectomy confirmed local vascular Ren-2 expression and angiotensin generation\",\n      \"pmids\": [\"2181319\", \"1592469\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific extrarenal tissues most responsible for systemic effects not fully dissected\", \"Whether human REN extrarenal expression has comparable functional impact was not addressed\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Biochemical identity of Ren-2 prorenin was established: recombinant Ren-2 prorenin expressed in CHO cells has a 42 kDa mass and pI of 6.5, with N-terminal sequencing confirming the predicted prosegment cleavage site.\",\n      \"evidence\": \"CHO cell expression, purification, SDS-PAGE, N-terminal sequencing\",\n      \"pmids\": [\"2202716\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Enzymatic kinetics and activation mechanism of prorenin not characterized in this study\"]\n    },\n    {\n      \"year\": 1996,\n      \"claim\": \"Genetic dispensability of Ren-2 for blood pressure homeostasis was demonstrated: Ren-2 knockout mice are normotensive, showing Ren-1d alone suffices for normal renin-angiotensin function, though plasma prorenin decreases and active renin increases.\",\n      \"evidence\": \"Gene targeting by homologous recombination in 129 strain mice; blood pressure and plasma renin/prorenin measurement\",\n      \"pmids\": [\"8952610\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Compensatory upregulation of Ren-1d was not fully characterized\", \"Physiological role of Ren-2-derived prorenin remained unclear\"]\n    },\n    {\n      \"year\": 1998,\n      \"claim\": \"The functional significance of local adrenal renin was established: high adrenal Ren-2 expression in transgenic rats elevates adrenocortical steroid production and impairs normal aldosterone regulation.\",\n      \"evidence\": \"In vivo measurement of adrenal renin, angiotensin II, and aldosterone in TGR(mREN2)27 rats\",\n      \"pmids\": [\"9694562\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single-lab study\", \"Whether endogenous adrenal renin levels have comparable paracrine effects was not tested\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"The non-redundant role of Ren-1d in kidney morphology was revealed: Ren-1d-null mice completely lack juxtaglomerular cell granulation and show macula densa abnormalities, which cannot be rescued by Ren-2 overexpression but are fully restored by a Ren-1d BAC transgene.\",\n      \"evidence\": \"BAC transgenesis and complementation on Ren-1d-null background; histopathology\",\n      \"pmids\": [\"10995772\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis for why Ren-2 cannot substitute for Ren-1d in granulation was not identified\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"The core transcriptional mechanism driving renin gene expression was defined: HOXD10 binds a TAATAAATCAA motif at the proximal promoter element and forms a ternary complex with PBX1b and PREP1; mutagenesis of either HOX or PBX half-site abolishes complex formation and dramatically reduces Ren-1c promoter activity.\",\n      \"evidence\": \"EMSA with purified HOX/PBX proteins, site-directed mutagenesis, reporter assays in renin-expressing As4.1 cells\",\n      \"pmids\": [\"11432851\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance not tested by chromatin immunoprecipitation in native tissue\", \"Whether other HOX paralogs contribute in different renin-expressing tissues was not addressed\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Renin-expressing cells in the brain were mapped to specific cardiovascular-control nuclei and identified as predominantly neurons, establishing the anatomical basis for a brain renin-angiotensin system.\",\n      \"evidence\": \"REN-eGFP transgenic mouse with NeuN/glia co-labeling and fluorescence microscopy\",\n      \"pmids\": [\"14625376\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional contribution of neuronal renin to central blood pressure regulation not directly tested\", \"Whether brain renin produces active angiotensin locally was not demonstrated\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"The domain-specific pathomechanisms of human REN mutations were resolved: signal peptide mutations reduce hydrophobicity and block ER translocation; prosegment mutations cause prorenin deposition in the ER-Golgi intermediate compartment; mature peptide mutations cause ER retention—each producing distinct trafficking defects and clinical phenotypes.\",\n      \"evidence\": \"International cohort of 111 individuals from 30 families; subcellular localization of mutant prorenin; signal peptide hydrophobicity analysis\",\n      \"pmids\": [\"32750457\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ER stress/unfolded protein response mediates tubular damage was not directly shown\", \"Rescue or therapeutic approaches not tested\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis for the non-redundancy of Ren-1d versus Ren-2 in juxtaglomerular granulation, the physiological significance of brain neuronal renin, whether ER stress pathways mediate kidney damage in human REN mutations, and the identity of trans-acting factors controlling adrenal cell-type-specific renin expression.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural comparison of Ren-1d and Ren-2 protein explaining granulation specificity\", \"Functional role of brain renin in central cardiovascular regulation not directly tested\", \"ER stress response not characterized in REN mutation-associated nephropathy\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [4, 14]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [4, 14]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [5, 6, 16]},\n      {\"term_id\": \"R-HSA-74160\", \"supporting_discovery_ids\": [10, 11]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [4]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"HOXD10\",\n      \"PBX1\",\n      \"PREP1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```\n\n--- ROUND 2 (R2/R3, augmented corpus) ---\n\n```json\n{\n  \"mechanistic_narrative\": \"Renin (REN) is an aspartyl protease that catalyzes the rate-limiting cleavage of angiotensinogen to angiotensin I, initiating the renin-angiotensin cascade that controls blood pressure, renal hemodynamics, and aldosterone secretion [PMID:2493678, PMID:2181319]. Synthesized as preprorenin with a 20-residue signal peptide and 46-residue prosegment, renin undergoes signal-peptide-directed ER translocation and is converted to active renin by the convertase PC1 in a secretory-granule-dependent manner; the prosegment contains 'gate' and 'handle' regions whose displacement permits reversible non-proteolytic activation [PMID:1597471, PMID:12684512]. Renin and prorenin bind the (pro)renin receptor, which increases catalytic efficiency fourfold and triggers angiotensin II–independent ERK1/2 and p38 MAPK/HSP27 signaling cascades that remodel the actin cytoskeleton [PMID:12045255, PMID:16940215]. Dominant mutations in the signal peptide, prosegment, or mature renin domain cause autosomal dominant tubulointerstitial kidney disease (ADTKD-REN) through distinct ER-stress and trafficking defects, while biallelic loss-of-function mutations cause autosomal recessive renal tubular dysgenesis [PMID:19664745, PMID:32750457, PMID:16116425].\",\n  \"teleology\": [\n    {\n      \"year\": 1983,\n      \"claim\": \"Determination of the full preprorenin primary structure from cDNA established that renin is synthesized as a 406-amino-acid precursor with a signal peptide and prosegment homologous to aspartyl proteinases, resolving the biosynthetic origin of circulating renin.\",\n      \"evidence\": \"cDNA library screening and nucleotide sequencing of human kidney renin mRNA\",\n      \"pmids\": [\"6324167\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No three-dimensional structural information yet available\", \"Processing mechanism of the prosegment unknown\", \"Tissue-specific transcriptional regulation not addressed\"]\n    },\n    {\n      \"year\": 1984,\n      \"claim\": \"Elucidation of the human REN gene structure (9 exons, single copy, ~12 kb) and comparative analysis of mouse Ren-1/Ren-2 loci revealed conserved organization with divergent 5′-flanking regions, providing the framework for understanding tissue-specific and allele-specific transcriptional regulation.\",\n      \"evidence\": \"Genomic DNA cloning, restriction mapping, and complete sequencing of human and mouse renin loci; S1 nuclease mapping of transcription start sites\",\n      \"pmids\": [\"6089171\", \"6391881\", \"6392850\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Specific transcription factors driving tissue-specific expression not identified\", \"Functional significance of IAP retroviral insertion in Ren-2 not directly proven\"]\n    },\n    {\n      \"year\": 1989,\n      \"claim\": \"The 2.5 Å crystal structure of recombinant human renin revealed a conserved aspartyl proteinase core with variable surface loops conferring substrate specificity, enabling rational inhibitor design and explaining renin's narrow substrate selectivity for angiotensinogen.\",\n      \"evidence\": \"X-ray crystallography with molecular dynamics refinement of recombinant human renin\",\n      \"pmids\": [\"2493678\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structure of renin bound to angiotensinogen not yet determined\", \"Prosegment conformation and activation mechanism not resolved structurally\"]\n    },\n    {\n      \"year\": 1990,\n      \"claim\": \"Transgenic expression of the mouse Ren-2 gene in rats caused severe hypertension despite low plasma active renin, demonstrating that extrarenal renin expression is sufficient to drive hypertension and establishing the concept of tissue-based renin-angiotensin systems.\",\n      \"evidence\": \"Transgenic rat generation (TGR(mREN2)27) with blood pressure measurement, renin activity assays, and subsequent vascular perfusion studies\",\n      \"pmids\": [\"2181319\", \"1592469\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of individual tissue sites (adrenal, vascular, brain) to hypertension not dissected\", \"Mechanism of prorenin activation in peripheral tissues unclear\"]\n    },\n    {\n      \"year\": 1992,\n      \"claim\": \"Identification of PC1 as the specific convertase that processes prorenin to active renin in a secretory-granule-dependent manner resolved the long-standing question of how prorenin activation is compartmentalized, explaining why non-granulated cells secrete only prorenin.\",\n      \"evidence\": \"Vaccinia virus co-expression of renin with PC1, PC2, or furin in granulated (GH4) versus non-granulated (CHO, BSC-40) cells; biosynthetic labeling and immunoprecipitation\",\n      \"pmids\": [\"1597471\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether PC1 is the sole physiological convertase in juxtaglomerular cells in vivo not confirmed\", \"Sorting signals directing prorenin to secretory granules not mapped\"]\n    },\n    {\n      \"year\": 2001,\n      \"claim\": \"Discovery that Ren-1c transcription requires an Abd-B HOX·PBX·PREP1 ternary complex at a proximal promoter element identified the first transcription factor complex controlling renin gene expression, answering how cell-type-specific transcription is achieved.\",\n      \"evidence\": \"EMSA, point mutagenesis of HOX/PBX binding sites, transfection-based transcription assays, and in vivo DNA binding studies in As4.1 juxtaglomerular cells\",\n      \"pmids\": [\"11432851\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether this HOX·PBX·PREP1 mechanism operates at the human REN promoter not shown\", \"Upstream signals that regulate HOX factor expression in juxtaglomerular cells unknown\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Cloning of the (pro)renin receptor revealed that renin binding to a dedicated receptor both enhances catalytic efficiency fourfold and triggers angiotensin II–independent ERK1/2 signaling, establishing a new signaling paradigm beyond renin's classical enzymatic role.\",\n      \"evidence\": \"Expression cloning, stable transfection, binding kinetics, angiotensinogen conversion assay, and MAP kinase phosphorylation in mesangial cells; confocal co-localization\",\n      \"pmids\": [\"12045255\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of receptor-mediated catalytic enhancement not resolved\", \"Physiological significance of receptor signaling in vivo not established at this point\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Mapping of the prosegment 'gate' and 'handle' regions revealed the molecular mechanism of reversible non-proteolytic prorenin activation, explaining how prorenin can gain enzymatic activity without prosegment cleavage.\",\n      \"evidence\": \"Region-specific antibody-based activation/inactivation assays at 4°C with equilibrium binding analysis; structure-guided antigen design\",\n      \"pmids\": [\"12684512\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No high-resolution structure of the prorenin-to-renin conformational transition\", \"Whether non-proteolytic activation occurs physiologically at the (pro)renin receptor not directly shown\"]\n    },\n    {\n      \"year\": 2006,\n      \"claim\": \"Demonstration that prorenin activates p38 MAPK/HSP27 signaling and drives actin cytoskeletal remodeling via the (pro)renin receptor, independently of angiotensin II, extended receptor signaling beyond ERK1/2 to a second major MAPK cascade with transcriptional consequences.\",\n      \"evidence\": \"p38 MAPK phosphorylation assays with SB203580 inhibitor, microarray profiling (~260 regulated genes), 2D proteomics, and immunoblotting in neonatal rat cardiomyocytes; pharmacological exclusion of AT1/AT2 and renin catalytic activity\",\n      \"pmids\": [\"16940215\", \"18212269\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"In vivo relevance of (pro)renin receptor–p38 signaling in cardiac pathology not demonstrated\", \"Downstream transcriptional effectors mediating cytoskeletal remodeling not identified\"]\n    },\n    {\n      \"year\": 2005,\n      \"claim\": \"Identification of biallelic REN loss-of-function mutations as a cause of autosomal recessive renal tubular dysgenesis established that renin is essential for human proximal tubular development.\",\n      \"evidence\": \"Linkage analysis and candidate gene sequencing in 9 families with 11 affected individuals showing fetal anuria and absent proximal tubular differentiation\",\n      \"pmids\": [\"16116425\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism by which angiotensin II drives tubular differentiation not elucidated\", \"Whether renin has angiotensin-independent developmental roles not addressed\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Discovery that dominant signal-peptide mutations in REN impair ER translocation, trigger the unfolded protein response, and cause progressive juxtaglomerular cell loss established the pathogenic mechanism of autosomal dominant tubulointerstitial kidney disease (ADTKD-REN).\",\n      \"evidence\": \"Linkage analysis, in vitro translation and ER translocation assays, ER stress marker analysis, cell growth assays, and kidney biopsy immunohistochemistry\",\n      \"pmids\": [\"19664745\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether ER stress is the sole mechanism or whether loss of renin secretion also contributes not fully separated\", \"Animal model recapitulating ADTKD-REN not yet reported\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Crystal structures of angiotensinogen alone (2.1 Å) and in complex with renin (4.4 Å) revealed that the angiotensin cleavage site is normally buried and requires a redox-sensitive conformational change for renin access, explaining why the oxidized form of angiotensinogen is the preferred substrate.\",\n      \"evidence\": \"X-ray crystallography of angiotensinogen and angiotensinogen–renin complex; redox state quantification in normal and pre-eclamptic plasma\",\n      \"pmids\": [\"20927107\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"High-resolution structure of the complex not available (4.4 Å limits mechanistic detail)\", \"Whether redox regulation of angiotensinogen is a physiological control point in vivo requires further testing\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"A large international cohort study defined three distinct ADTKD-REN subtypes based on mutation location (signal peptide, prosegment, mature renin), each with a different trafficking defect and clinical trajectory, unifying the genotype-phenotype spectrum of dominant renin mutations.\",\n      \"evidence\": \"Genotyping of 111 individuals from 30 families, cellular trafficking studies, secretion assays, signal peptide hydrophobicity analysis, survival analysis\",\n      \"pmids\": [\"32750457\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Therapeutic strategies to mitigate ER stress or restore trafficking not tested\", \"Whether modifier genes influence ADTKD-REN progression not explored\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Key unresolved questions include the structural basis of (pro)renin receptor–mediated signaling, the in vivo physiological relevance of angiotensin II–independent (pro)renin receptor pathways, and the cell-biological mechanisms linking ER-trapped renin mutants to progressive kidney fibrosis.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No high-resolution structure of renin bound to the (pro)renin receptor\", \"In vivo genetic models dissecting receptor signaling from catalytic function lacking\", \"Mechanism of fibrosis downstream of ER stress in ADTKD-REN not defined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 9, 15, 29, 36]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 9, 29, 36]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [35, 38]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [11, 14, 15]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"GO:0162582\", \"supporting_discovery_ids\": [28, 32, 33]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [28, 32, 33]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [31, 35, 38]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"AGT\",\n      \"ATP6AP2\",\n      \"PCSK1\",\n      \"PBX1\",\n      \"PREP1\",\n      \"HOXD10\",\n      \"HOXA10\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}