{"gene":"ECE1","run_date":"2026-06-09T23:54:42","timeline":{"discoveries":[{"year":1994,"finding":"ECE-1 is a membrane-bound neutral metalloprotease that catalyzes the proteolytic conversion of big endothelin-1 (38-residue) to active endothelin-1 (21-residue) by cleavage at Trp21-Val22. Transfection of ECE-1 cDNA into cultured cells conferred the ability to secrete mature ET-1, and ECE-1 interacts with big ET-1 at the cell surface.","method":"cDNA transfection into cultured cells, functional secretion assay, cell-surface interaction assay","journal":"Cell","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct functional reconstitution in transfected cells with clear substrate-product conversion; foundational paper replicated by multiple subsequent labs","pmids":["8062389"],"is_preprint":false},{"year":1994,"finding":"ECE-1 is a zinc metalloprotease containing the HEXXH (HELTH) catalytic motif. Purified bovine ECE-1 was confirmed by peptide sequencing and the recombinant human enzyme has the same catalytic activity as the native enzyme.","method":"Enzyme purification, tryptic peptide sequencing, heterologous expression in cultured cells and Xenopus oocytes, activity assay","journal":"FEBS letters","confidence":"High","confidence_rationale":"Tier 1 / Strong — direct biochemical purification, active-site motif identification, and reconstituted recombinant activity","pmids":["7805846"],"is_preprint":false},{"year":1997,"finding":"ECE-1 exists as three isoforms (ECE-1a, ECE-1b, ECE-1c) generated from a single gene via alternative promoters, differing only in their N-terminal cytoplasmic tails. ECE-1a and ECE-1c localize to the cell surface, whereas ECE-1b localizes intracellularly with significant co-localization with the trans-Golgi network marker. All three isoforms have similar kinetic constants (Km, kcat, Vmax) for processing big endothelin-1, -2, and -3.","method":"Molecular cloning, immunofluorescence microscopy, subcellular localization, kinetic enzyme assays","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1–2 / Strong — direct subcellular localization by immunofluorescence tied to functional isoform characterization; kinetic assays performed for all isoforms","pmids":["9396733"],"is_preprint":false},{"year":1999,"finding":"Two di-leucine-based motifs in the N-terminal cytoplasmic tail of ECE-1b are responsible for its intracellular localization. One motif (LL) is unique to ECE-1b and responsible for its exclusive intracellular retention; a second motif (LV) is shared with ECE-1c and accounts for ECE-1c's reduced cell-surface expression relative to ECE-1a. Mutation of both motifs causes strong cell-surface appearance of ECE-1b.","method":"Chimeric protein construction, point mutagenesis, electron microscopy immunocytochemistry in CHO cells","journal":"Journal of cell science","confidence":"High","confidence_rationale":"Tier 1 / Moderate — site-directed mutagenesis with functional subcellular localization readout; single lab but multiple orthogonal methods (EM immunocytochemistry + chimeric proteins + mutagenesis)","pmids":["10462527"],"is_preprint":false},{"year":1999,"finding":"A nine amino-acid segment in the cytosolic tail of ECE-1b containing two leucine residues is sufficient to redirect neprilysin (NEP) from the cell surface to an intracellular compartment, establishing this segment as an autonomous intracellular retention/targeting signal.","method":"ECE/NEP chimeric protein construction, transfection in MDCK cells, site-directed mutagenesis, subcellular localization","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 / Moderate — domain-swap chimera with mutagenesis identifies minimal targeting signal; single lab with two orthogonal methods","pmids":["10377252"],"is_preprint":false},{"year":1998,"finding":"ECE-1b localizes to early and late endosomes (not cell surface) in polarized MDCK cells. Phosphoramidon treatment increases ECE-1b protein level by slowing its lysosomal degradation (half-life extended from 2.8 h to 7.5 h), without changing mRNA levels, indicating rapid turnover of ECE-1b through endosomal-lysosomal compartments.","method":"Cell-surface biotinylation, immunofluorescence, anti-Rab5/Rab7 co-localization, pulse-chase immunoprecipitation, Western blot, Northern blot, confocal microscopy","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (pulse-chase, compartment marker co-localization, pharmacological inhibition) in single lab","pmids":["9657986"],"is_preprint":false},{"year":1999,"finding":"A fourth isoform, ECE-1d, is generated from an additional promoter upstream of the third exon of the ECE-1 gene. ECE-1d has comparable converting activity to the other isoforms and is expressed at the cell surface, though less strongly than ECE-1a.","method":"Molecular cloning, promoter mapping, functional expression assay, cell-surface localization","journal":"European journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — single lab, cloning and functional expression with surface localization but limited mechanistic depth","pmids":["10491078"],"is_preprint":false},{"year":2000,"finding":"Genetic epistasis analysis using ECE-1/ECE-2 double-knockout mice showed that ECE-2 contributes to cardiac outflow and atrioventricular valve development redundantly with ECE-1, but significant residual ET-1/ET-2 remained in double-null embryos, indicating that additional proteases distinct from ECE-1 and ECE-2 can activate ET-1 in vivo.","method":"Homologous recombination knockout mice, compound mutant analysis, ET-1/ET-2 peptide measurement","journal":"The Journal of clinical investigation","confidence":"High","confidence_rationale":"Tier 2 / Strong — genetic epistasis with double-KO mice, quantitative ET-1/ET-2 measurement; independently generated null alleles","pmids":["10811845"],"is_preprint":false},{"year":2003,"finding":"ECE-1 (Ece1) and Tbx1 define distinct, non-interacting pathways in aortic arch morphogenesis. Ece1 is required for regression of cranial arch arteries and growth of caudal arch arteries (linked to endothelin-1 pathway neural crest function), whereas Tbx1 is required for early formation and growth of pharyngeal arch arteries. Compound Ece1/Tbx1 mutants showed no genetic interaction.","method":"Genetic epistasis in compound mutant mice, morphological analysis of pharyngeal arch artery remodeling","journal":"Developmental dynamics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean genetic epistasis with compound mutants, single lab, two-gene analysis","pmids":["12950083"],"is_preprint":false},{"year":2003,"finding":"The homeobox transcription factor Nkx2-5 activates all three ECE-1 isoform promoters (ECE-1a, ECE-1b, ECE-1c) in cardiomyoblasts. The ECE-1b promoter contains an Nkx2-5 consensus site required for direct activation; ECE-1a and ECE-1c promoters are activated indirectly. Stable Nkx2-5 overexpression increases ECE-1 isoform mRNA levels.","method":"Transient transfection reporter assays, gel shift assays (EMSA), site-directed mutagenesis of promoter elements, stable overexpression with RNase protection assay, Northern blot, real-time PCR","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — EMSA plus reporter mutagenesis plus stable overexpression; single lab with multiple methods","pmids":["12824294"],"is_preprint":false},{"year":1997,"finding":"The ECE-1 gene is organized into 19 exons spanning >68 kb, mapped to chromosome 1p36. Two isoform mRNAs (ECE-1a and ECE-1b) are transcribed from two distinct promoters with different tissue distributions.","method":"Genomic cloning, exon-intron mapping, FISH chromosomal localization, tissue distribution analysis","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct genomic structural analysis with chromosomal mapping; single lab","pmids":["8530372"],"is_preprint":false},{"year":2000,"finding":"The ECE-1c promoter contains two positive regulatory regions (-142/-240 and -240/-490) likely binding GATA and ETS transcription factors, multiple transcriptional start sites (~-110, -140, and -350 bp), and a crucial E2F cis-element required for basal ECE-1c promoter activity as demonstrated by site-directed mutagenesis.","method":"Reporter gene assays with serial deletion mutants, transfection into endothelial and epithelial cells, site-directed mutagenesis, RNase protection assay, 5'-RACE","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — mutagenesis of promoter elements in multiple cell lines; single lab with several orthogonal methods","pmids":["10682850"],"is_preprint":false},{"year":2014,"finding":"An arterial-specific enhancer in the human ECE1 locus is cooperatively activated by the transcription factors Sox17, FoxC2, and Etv2 through a conserved FOX:ETS composite motif and a SOX binding site. In transgenic mice, enhancer activity is restricted to arterial endothelium and endocardium by embryonic day 9.5.","method":"Transgenic mouse reporter assays, in vivo enhancer activity analysis, transcription factor binding site mutagenesis","journal":"Developmental biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vivo transgenic reporter with mutagenesis of binding sites; single lab","pmids":["25179465"],"is_preprint":false},{"year":2016,"finding":"The TIMAP-protein phosphatase 1 (PP1c) complex physically interacts with ECE-1 and dephosphorylates it. PKC phosphorylates ECE-1, increasing its plasma membrane level and ET-1 secretion; TIMAP depletion reduces PP1c activity toward ECE-1, leading to elevated ECE-1 membrane abundance and elevated ET-1 production. Thus, PKC-phosphorylated ECE-1 is a TIMAP-PP1c substrate.","method":"Co-immunoprecipitation (protein-protein interaction), TIMAP siRNA knockdown, PKC activation, Western blot membrane fractionation, ET-1 secretion assay","journal":"The international journal of biochemistry & cell biology","confidence":"Medium","confidence_rationale":"Tier 2–3 / Moderate — reciprocal co-IP showing TIMAP-PP1c-ECE1 complex, pharmacological and genetic perturbation with functional readout; single lab","pmids":["26806547"],"is_preprint":false},{"year":2008,"finding":"siRNA-mediated knockdown of ECE-1 in prostate cancer stromal or epithelial cells reduces PC-3 epithelial cell invasion and migration. Re-addition of ET-1 only partially recovers invasion, indicating both ET-1-dependent and ET-1-independent functions for ECE-1. ECE-1 inhibition reduces focal adhesion kinase (FAK) phosphorylation; conversely, ECE-1 overexpression increases FAK phosphorylation, linking ECE-1 to FAK-mediated invasion signaling.","method":"siRNA/shRNA knockdown, Matrigel invasion assay, ET-1 rescue experiment, ECE-1 specific inhibitor treatment, Western blot for FAK phosphorylation, transient overexpression","journal":"British journal of cancer / Canadian journal of physiology and pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — siRNA knockdown and overexpression with pathway readout (FAK phosphorylation); two publications from same lab with consistent findings","pmids":["18781169","20725143"],"is_preprint":false},{"year":2008,"finding":"ECE-1c and ECE-1a isoforms have opposing effects on prostate cancer cell invasion: ECE-1c overexpression increases PC-3 invasiveness through Matrigel, whereas ECE-1a expression suppresses invasion. Transient ECE-1a expression in stromal cells counteracts the pro-invasive effect of ECE-1c in epithelial cells.","method":"Transient isoform-specific overexpression, siRNA knockdown, Matrigel invasion assay, co-culture experiments","journal":"British journal of cancer","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — isoform-specific overexpression and knockdown with functional invasion readout; single lab","pmids":["18781169"],"is_preprint":false},{"year":2014,"finding":"ECE-1 expression is post-transcriptionally regulated by alternative polyadenylation (APA). The ECE-1 3'UTR markedly inhibits protein expression, and APA produces transcripts with truncated 3'UTRs that promote elevated ECE-1 protein expression. Abolition of APA sites in a reporter construct reduced protein expression in prostate cancer cells.","method":"Reporter assay with 3'UTR constructs, APA site mutagenesis, comparison of 3'UTR length variants","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — reporter assay with mutagenesis of APA sites; single lab, single method approach","pmids":["24497914"],"is_preprint":false},{"year":2013,"finding":"R-568 (calcimimetic) inhibits ECE-1 enzymatic activity by expelling zinc from the enzyme's active site, as demonstrated by restoration of activity upon addition of exogenous zinc and reduced zinc content in immunoprecipitated ECE-1 from R-568-treated cells. This results in decreased ET-1 synthesis despite increased ECE-1 protein levels.","method":"ECE-1 activity assay, zinc supplementation rescue experiment, immunoprecipitation with zinc measurement, Western blot, ELISA for ET-1","journal":"Pharmacological research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct mechanistic demonstration of zinc ejection from active site with functional and biochemical rescue; single lab with multiple orthogonal methods","pmids":["23911580"],"is_preprint":false},{"year":2023,"finding":"ECE-1 physically interacts with the pleckstrin homology (PH) domain of AKT and facilitates AKT translocation to the plasma membrane for activation, promoting lung cancer cell proliferation independent of its canonical ET-1 producing function. ECE-1 knockdown reduces AKT activation and tumor growth; AKT inhibition counteracts the growth-inhibitory effect of ECE-1 knockdown.","method":"Co-immunoprecipitation, immunofluorescence co-localization, RNA sequencing, ECE-1 knockdown (siRNA/shRNA), AKT inhibitor rescue, in vitro and xenograft tumor growth assays","journal":"The journal of gene medicine","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — co-IP demonstrating ECE1-AKT PH domain interaction, functional rescue with AKT inhibitor, in vivo xenograft validation; single lab","pmids":["37897251"],"is_preprint":false},{"year":2001,"finding":"Antisense oligodeoxynucleotide knockdown of ECE-1c in bovine pulmonary artery smooth muscle cells markedly reduced ECE-1c mRNA and ECE-1 protein, but basal and TNFα-stimulated ET-1 release were largely unaffected, indicating that an endopeptidase distinct from ECE-1 is mainly responsible for big ET-1 processing in VSMC.","method":"Antisense oligodeoxynucleotide treatment, RT-PCR, Western blot, ET-1 ELISA","journal":"Molecular pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — antisense knockdown with protein-level confirmation and functional ET-1 readout; negative result is mechanistically informative; single lab","pmids":["11160849"],"is_preprint":false},{"year":1997,"finding":"ECE activity in human vascular smooth muscle (endothelium-denuded umbilical vein) is phosphoramidon-sensitive and can convert big ET-1, big ET-2(1-37), big ET-2(1-38), and big ET-3 to their mature biologically active forms, demonstrating broader substrate specificity than ET-1 alone.","method":"Pharmacological inhibition with phosphoramidon, functional vasoconstriction assay, radioimmunoassay for ET immunoreactivity","journal":"British journal of pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — functional ex vivo preparation with pharmacological inhibition; demonstrates substrate breadth; single lab","pmids":["9422810"],"is_preprint":false},{"year":2003,"finding":"ECE-1 inhibition reduces ET-1 expression and cell invasiveness in MCF-7 breast cancer cells (54.3% of controls) using the selective ECE-1 inhibitor RO 67-7447.","method":"Selective ECE-1 inhibitor treatment, ET-1 expression assay, cell invasion assay","journal":"Breast cancer research and treatment","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pharmacological inhibitor study with functional invasion readout but no direct mechanistic pathway placement; single lab, single method type","pmids":["17295044"],"is_preprint":false},{"year":2006,"finding":"siRNA-mediated knockdown of ECE-1 in oral squamous cell carcinoma (SCC) cells reduces SCC cell proliferation. ET-1 alone stimulates proliferation of oral SCC cells, and this is blocked by antagonists of either ETA or ETB receptors.","method":"siRNA knockdown, ECE-specific inhibitor, cell proliferation assay, receptor antagonist experiments","journal":"International journal of cancer","confidence":"Low","confidence_rationale":"Tier 3 / Weak — siRNA knockdown with proliferation readout; pathway placement via ET-1 and receptor antagonists; single lab","pmids":["16217751"],"is_preprint":false},{"year":1997,"finding":"ECE-1 has an ectodomain structurally related to neutral endopeptidase 24.11 (NEP), and is a type II integral membrane protein expressed predominantly in endothelial cells. Multiple isoforms (ECE-1a, ECE-1b, ECE-1c, and ECE-2) exist with different characteristics.","method":"Sequence analysis, comparative biochemistry, structural homology analysis","journal":"FASEB journal","confidence":"Medium","confidence_rationale":"Tier 2 / Strong — review synthesizing experimental findings from multiple labs; structural homology confirmed by protein biochemistry","pmids":["9141502"],"is_preprint":false},{"year":2008,"finding":"ERK signaling pathway activation in hepatic stellate cells (after bile duct ligation) regulates ECE-1 expression: inhibition of ERK in stellate cells from BDL-injured liver leads to decreased ECE-1 expression, linking TGF-β/ERK signaling to ECE-1 transcriptional regulation in liver fibrosis.","method":"Pharmacological ERK inhibition, qRT-PCR for ECE-1, stellate cell isolation, phospho-Smad3 and MAP kinase Western blot","journal":"The American journal of pathology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — pharmacological pathway inhibition with mRNA readout; single lab, limited mechanistic detail in abstract","pmids":["18753413"],"is_preprint":false},{"year":2008,"finding":"ECE protein is expressed in the embryonic chick heart in endothelial cells, mesenchymal cells, myocytes, and is enriched in trabeculae and nascent ventricular conduction system. ET receptor blockade with bosentan delayed activation sequence maturation, and hemodynamic loading modifies myocardial ECE expression, supporting a role for ECE in cardiac conduction system differentiation.","method":"Immunohistochemistry with custom antibody, in vivo ET receptor blockade (bosentan), experimental hemodynamic loading, Western blot","journal":"Developmental dynamics","confidence":"Low","confidence_rationale":"Tier 3 / Moderate — direct localization by IHC plus pharmacological perturbation with functional conduction readout; single lab in avian model","pmids":["18489007"],"is_preprint":false},{"year":2023,"finding":"Tspan8 (tetraspanin) physically associates with ECE-1 and amplifies its activity in converting big ET-1 to ET-1, as demonstrated in colon carcinoma cells transduced with Tspan8 and in ileum tissue from tspan8 knockout mice versus wild-type mice.","method":"Mass spectrometry, Western blot co-immunoprecipitation, Tspan8 transduction in Isreco1 cells, tspan8 knockout mouse tissue analysis, ECE-1 activity assay","journal":"Cancers","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — MS identification of complex confirmed by co-IP with functional activity assay in both cell model and KO mouse tissue; single lab","pmids":["37835445"],"is_preprint":false},{"year":2020,"finding":"ECE-1 knockout mice show reduced kidney fibrosis, tubular injury, macrophage infiltration, fibroblast number, and myofibroblast formation after unilateral ureteral obstruction, associated with reduced TGF-β1 and α-SMA protein levels, demonstrating that ECE-1-mediated ET-1 activation drives pro-fibrotic signaling in the kidney.","method":"ECE-1 knockout mice, unilateral ureteral obstruction model, histopathology, immunostaining (F4/80, FSP-1, α-SMA), qRT-PCR, Western blot","journal":"Life sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — clean KO with defined cellular phenotypes and molecular pathway readouts; single lab","pmids":["32768584"],"is_preprint":false},{"year":2003,"finding":"Phosphoramidon differentially affects ECE-1 isoforms: it increases intracellular ECE-1a and ECE-1b protein levels by prolonging their half-lives (via inhibition of intracellular degradation) but does not affect ECE-1c protein levels. mRNA levels are unchanged, indicating post-translational regulation.","method":"Metabolic pulse-chase labeling, immunoprecipitation, Western blot, Northern blot, immunocytochemistry in CHO cell lines stably expressing individual ECE-1 isoforms","journal":"Journal of cardiovascular pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — pulse-chase with immunoprecipitation directly measuring half-lives; single lab, multiple isoforms tested","pmids":["12827039"],"is_preprint":false},{"year":1997,"finding":"ECE-1 in endothelial cells (EA.hy926) is an integral membrane protein, as demonstrated by detergent solubilization and temperature-induced phase separation. Greater than 75% of total ECE activity could be immunoprecipitated with a monoclonal antibody raised against neutral endopeptidase E-24.11, indicating a shared epitope between ECE and NEP.","method":"Detergent phase separation, antibody immunoprecipitation of enzymatic activity","journal":"Journal of cardiovascular pharmacology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — biochemical fractionation and antibody cross-reactivity; single method, single lab","pmids":["8587468"],"is_preprint":false},{"year":1997,"finding":"ECE-1 inhibition by phosphoramidon in big ET-1-stimulated human umbilical vein smooth muscle preparations blocks vasoconstriction in a concentration-dependent manner, confirming that smooth muscle ECE converts big ET-1 to active ET-1 via a phosphoramidon-sensitive mechanism.","method":"Ex vivo vascular preparation, phosphoramidon pharmacological inhibition, concentration-response analysis","journal":"British journal of pharmacology","confidence":"Low","confidence_rationale":"Tier 3 / Weak — functional pharmacological inhibition in ex vivo preparation; single lab, indirect enzymatic evidence","pmids":["9422810"],"is_preprint":false},{"year":1997,"finding":"Big ET-1 peptide analogues [Phe21]big ET-1(18-34) and [Ala31]big ET-1(18-34) inhibit ECE-1 activity in different fashions: [Phe21]big ET-1(18-34) is a competitive inhibitor (Ki=20.6 µM) and [Ala31]big ET-1(18-34) is a noncompetitive inhibitor (Ki=35.6 µM), indicating ECE-1 recognizes big ET-1 both at the P1 position and at the C-terminal region through distinct mechanisms.","method":"Kinetic analysis of ECE-1 inhibition using solubilized membranes from ECE-1-expressing CHO-K1 cells, competitive vs. noncompetitive inhibitor determination","journal":"FEBS letters","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — direct enzyme kinetics with mechanistic interpretation; single lab, single method","pmids":["9450558"],"is_preprint":false}],"current_model":"ECE-1 is a zinc-dependent, type II integral membrane metalloprotease (HEXXH motif) that catalyzes the final, rate-limiting cleavage of big endothelin-1 at Trp21-Val22 to generate the potent vasoconstrictor ET-1; it exists as four isoforms (a–d) generated by alternative promoters, whose distinct N-terminal di-leucine motifs determine differential subcellular localization (cell surface for ECE-1a/c/d, trans-Golgi/endosomal-lysosomal pathway for ECE-1b), and whose activity is regulated post-translationally by PKC phosphorylation/TIMAP-PP1c dephosphorylation, by zinc chelation (calcimimetics), and by the tetraspanin Tspan8 (which amplifies activity); beyond ET-1 production, ECE-1 also promotes cell invasion and proliferation through ET-1-independent mechanisms including direct interaction with the AKT pleckstrin homology domain to facilitate membrane translocation and AKT activation."},"narrative":{"mechanistic_narrative":"ECE-1 is a zinc-dependent, type II integral membrane metalloprotease that catalyzes the final, rate-limiting step in endothelin biosynthesis, cleaving big endothelin-1 at Trp21-Val22 to generate the active vasoconstrictor ET-1 [PMID:8062389, PMID:7805846]. Catalysis depends on a HEXXH (HELTH) zinc-binding active site, and the enzyme converts big ET-1, -2, and -3, with substrate recognition occurring at both the P1 scissile position and the C-terminal region of big ET-1 [PMID:7805846, PMID:9422810, PMID:9450558]. A single gene on chromosome 1p36 produces four isoforms (a–d) from alternative promoters that share catalytic activity but differ only in their N-terminal cytoplasmic tails; di-leucine-based motifs in these tails act as autonomous targeting signals that route ECE-1b to intracellular endosomal-lysosomal compartments while ECE-1a, -1c, and -1d reach the cell surface [PMID:9396733, PMID:10462527, PMID:10377252, PMID:9657986, PMID:10491078, PMID:8530372]. ECE-1 abundance and activity are controlled post-translationally: isoform half-lives are set by intracellular degradation [PMID:9657986, PMID:12827039], PKC phosphorylation increases plasma-membrane ECE-1 and ET-1 secretion while the TIMAP-PP1c phosphatase complex reverses this [PMID:26806547], the calcimimetic R-568 inhibits the enzyme by ejecting active-site zinc [PMID:23911580], and the tetraspanin Tspan8 physically associates with ECE-1 to amplify big ET-1 conversion [PMID:37835445]. Transcription of the isoform promoters is driven by cardiac and vascular regulators including Nkx2-5 and an arterial endothelial enhancer cooperatively bound by Sox17, FoxC2, and Etv2 [PMID:12824294, PMID:10682850, PMID:25179465]. In vivo, ECE-1 acts redundantly with ECE-2 in cardiac outflow and aortic arch artery remodeling, with residual ET activation indicating additional non-ECE proteases, and ECE-1-mediated ET-1 production drives pro-fibrotic signaling in the kidney [PMID:10811845, PMID:12950083, PMID:32768584]. Beyond ET-1 generation, ECE-1 promotes cancer cell invasion and proliferation through both ET-1-dependent and ET-1-independent routes, including modulation of FAK phosphorylation and direct interaction with the AKT pleckstrin homology domain to facilitate AKT membrane translocation and activation [PMID:18781169, PMID:20725143, PMID:37897251].","teleology":[{"year":1994,"claim":"Established the core identity and function of ECE-1: that a single membrane metalloprotease executes the rate-limiting conversion of big ET-1 to mature ET-1, the molecular basis of endothelin production.","evidence":"cDNA transfection with functional ET-1 secretion assay; enzyme purification, peptide sequencing, and recombinant activity reconstitution identifying the HEXXH zinc motif","pmids":["8062389","7805846"],"confidence":"High","gaps":["Cleavage at Trp21-Val22 defined for ET-1 but full substrate scope not yet mapped","No structural model of the catalytic ectodomain"]},{"year":1997,"claim":"Defined the gene architecture and isoform diversity, showing multiple promoters generate catalytically equivalent isoforms differing only in N-terminal tails — the basis for differential localization despite shared enzymology.","evidence":"Genomic cloning, FISH mapping, molecular cloning, immunofluorescence, and kinetic enzyme assays across isoforms in cultured cells","pmids":["8530372","9396733","9141502"],"confidence":"Medium","gaps":["Why distinct subcellular pools are needed for an enzyme with one substrate not resolved","Tissue-specific isoform usage only partly characterized"]},{"year":1999,"claim":"Identified the molecular targeting signals that route ECE-1b intracellularly, showing di-leucine motifs are autonomous retention signals sufficient to redirect even a heterologous protease.","evidence":"Chimeric protein and ECE/NEP domain-swap construction, point mutagenesis, and EM immunocytochemistry in CHO and MDCK cells; identification of a fourth isoform ECE-1d","pmids":["10462527","10377252","10491078"],"confidence":"High","gaps":["Adaptor proteins reading the di-leucine motifs not identified","Functional consequence of intracellular versus surface processing pools unclear"]},{"year":2000,"claim":"Tested ECE-1 sufficiency in vivo through genetics, revealing redundancy with ECE-2 and the existence of additional ET-activating proteases — refining ECE-1 from sole to principal converting enzyme.","evidence":"ECE-1/ECE-2 double-knockout mice with quantitative ET-1/ET-2 peptide measurement; antisense knockdown in pulmonary artery smooth muscle cells","pmids":["10811845","11160849"],"confidence":"High","gaps":["Identity of the residual non-ECE ET-converting protease(s) unknown","Cell-type-specific reliance on ECE-1 versus alternatives unmapped"]},{"year":2003,"claim":"Connected ECE-1 to developmental morphogenesis and its transcriptional control, placing the gene within endothelin-pathway neural crest function and cardiac regulatory networks.","evidence":"Compound mutant mouse epistasis for aortic arch remodeling; EMSA, reporter mutagenesis, and overexpression linking Nkx2-5 to isoform promoters; enzyme kinetics defining big ET-1 recognition","pmids":["12950083","12824294","9450558","12827039"],"confidence":"Medium","gaps":["Direct downstream developmental targets of ECE-1-generated ET-1 not defined","Promoter regulation studied largely in cell lines"]},{"year":2014,"claim":"Resolved multilayered control of ECE-1 expression — an arterial endothelial enhancer and post-transcriptional 3'UTR/alternative polyadenylation regulation tuning protein output.","evidence":"Transgenic mouse enhancer reporter with Sox17/FoxC2/Etv2 binding-site mutagenesis; 3'UTR reporter assays with APA-site mutagenesis in prostate cancer cells","pmids":["25179465","24497914"],"confidence":"Medium","gaps":["Whether APA regulation operates in vascular tissue not shown","trans-factors controlling APA choice unidentified"]},{"year":2016,"claim":"Defined post-translational regulation of ECE-1 surface abundance through a phosphorylation cycle, identifying a specific kinase and phosphatase complex acting on the enzyme.","evidence":"Reciprocal co-IP for TIMAP-PP1c-ECE-1, TIMAP siRNA, PKC activation, membrane fractionation, and ET-1 secretion assays","pmids":["26806547"],"confidence":"Medium","gaps":["Phosphorylation sites on ECE-1 not mapped","Which isoforms are PKC substrates not resolved","Single lab, no reciprocal phosphatase validation in vivo"]},{"year":2023,"claim":"Extended ECE-1 function beyond proteolysis, demonstrating activity amplification by a tetraspanin partner and an ET-1-independent scaffolding role in promoting AKT activation and tumor growth.","evidence":"Mass spectrometry and co-IP for Tspan8 association with KO mouse validation; co-IP/co-localization mapping ECE-1 to the AKT PH domain with AKT-inhibitor rescue and xenograft assays","pmids":["37835445","37897251"],"confidence":"Medium","gaps":["Structural basis of the ECE-1–AKT PH domain interaction unknown","Whether the AKT-promoting role requires catalytic activity not tested","Mechanism by which Tspan8 amplifies activity unresolved"]},{"year":null,"claim":"It remains unknown how ECE-1's distinct subcellular pools and isoform-specific functions are integrated, and whether its non-catalytic AKT-scaffolding activity operates in normal physiology beyond cancer.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No high-resolution structure of full-length ECE-1 or its complexes","Identity of residual ET-converting proteases unresolved","Catalytic versus scaffolding contributions to disease phenotypes not separated"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0140096","term_label":"catalytic activity, acting on a protein","supporting_discovery_ids":[0,1,2,20,31]},{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,1]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[0,2,3,6,29]},{"term_id":"GO:0005794","term_label":"Golgi apparatus","supporting_discovery_ids":[2]},{"term_id":"GO:0005768","term_label":"endosome","supporting_discovery_ids":[5]},{"term_id":"GO:0005764","term_label":"lysosome","supporting_discovery_ids":[5,28]}],"pathway":[{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[0,13,18]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[7,8,12,25]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[0,1]},{"term_id":"R-HSA-1643685","term_label":"Disease","supporting_discovery_ids":[14,18,27]}],"complexes":["TIMAP-PP1c-ECE-1 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are improved by introduction of a 7-azatryptophan in P2' position.","date":"2004","source":"The journal of peptide research : official journal of the American Peptide Society","url":"https://pubmed.ncbi.nlm.nih.gov/15009531","citation_count":5,"is_preprint":false},{"pmid":"3028334","id":"PMC_3028334","title":"Molecular pathogenesis of equine coital exanthema (ECE): temperature sensitivity (TS) and restriction endonuclease (RE) fragment profiles of several field isolates.","date":"1987","source":"Archives of virology","url":"https://pubmed.ncbi.nlm.nih.gov/3028334","citation_count":5,"is_preprint":false},{"pmid":"12067547","id":"PMC_12067547","title":"Synthesis of triazole-Tethered pyrrolidine libraries: novel ECE inhibitors.","date":"2002","source":"Bioorganic & medicinal chemistry letters","url":"https://pubmed.ncbi.nlm.nih.gov/12067547","citation_count":5,"is_preprint":false},{"pmid":"27036146","id":"PMC_27036146","title":"Association between ECE1 gene polymorphisms and risk of intracerebral haemorrhage.","date":"2016","source":"The Journal of international medical research","url":"https://pubmed.ncbi.nlm.nih.gov/27036146","citation_count":4,"is_preprint":false},{"pmid":"32107880","id":"PMC_32107880","title":"Association of ECE1 gene polymorphisms and essential hypertension risk in the Northern Han Chinese: A case-control study.","date":"2020","source":"Molecular genetics & genomic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/32107880","citation_count":4,"is_preprint":false},{"pmid":"38465437","id":"PMC_38465437","title":"siRNA Targeting ECE-1 Partially Reverses Pulmonary Arterial Hypertensionassociated Damage in a Monocrotaline Model.","date":"2024","source":"Current molecular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/38465437","citation_count":4,"is_preprint":false},{"pmid":"32595726","id":"PMC_32595726","title":"Phenylethanol Glycosides Protect Myocardial Hypertrophy Induced by Abdominal Aortic Constriction via ECE-1 Demethylation Inhibition and PI3K/PKB/eNOS Pathway Enhancement.","date":"2020","source":"Evidence-based complementary and alternative medicine : eCAM","url":"https://pubmed.ncbi.nlm.nih.gov/32595726","citation_count":4,"is_preprint":false},{"pmid":"31637345","id":"PMC_31637345","title":"The -839(A/C) Polymorphism in the ECE1 Isoform b Promoter Associates With Osteoporosis and Fractures.","date":"2019","source":"Journal of the Endocrine Society","url":"https://pubmed.ncbi.nlm.nih.gov/31637345","citation_count":3,"is_preprint":false},{"pmid":"12827039","id":"PMC_12827039","title":"The effects of phosphoramidon on the expression of human endothelin-converting enzyme-1 (ECE-1) isoforms.","date":"2003","source":"Journal of cardiovascular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/12827039","citation_count":3,"is_preprint":false},{"pmid":"9873497","id":"PMC_9873497","title":"Synthesis of novel substituted pyridines as inhibitors of endothelin converting enzyme-1 (ECE-1).","date":"1998","source":"Bioorganic & medicinal chemistry letters","url":"https://pubmed.ncbi.nlm.nih.gov/9873497","citation_count":3,"is_preprint":false},{"pmid":"37835445","id":"PMC_37835445","title":"The Tetraspanin Tspan8 Associates with Endothelin Converting Enzyme ECE1 and Regulates Its Activity.","date":"2023","source":"Cancers","url":"https://pubmed.ncbi.nlm.nih.gov/37835445","citation_count":2,"is_preprint":false},{"pmid":"39787422","id":"PMC_39787422","title":"Candida Albicans Candidalysin ECE1 Gene - A Potent Virulence Factor for Oral Squamous Cell Carcinoma and Oral Potentially Malignant Disorders.","date":"2024","source":"Indian journal of dental research : official publication of Indian Society for Dental Research","url":"https://pubmed.ncbi.nlm.nih.gov/39787422","citation_count":2,"is_preprint":false},{"pmid":"29978582","id":"PMC_29978582","title":"ECE-1 overexpression in head and neck cancer is associated with poor tumor differentiation and patient outcome.","date":"2018","source":"Oral diseases","url":"https://pubmed.ncbi.nlm.nih.gov/29978582","citation_count":2,"is_preprint":false},{"pmid":"8587468","id":"PMC_8587468","title":"Expression of ECE and related membrane peptidases in the EA.hy926 cell line.","date":"1995","source":"Journal of cardiovascular pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/8587468","citation_count":2,"is_preprint":false},{"pmid":"31777301","id":"PMC_31777301","title":"Effects of ECE-1b rs213045 and rs2038089 polymorphisms on the development of contrast-induced acute kidney injury in patients with acute coronary syndrome.","date":"2019","source":"The Journal of international medical research","url":"https://pubmed.ncbi.nlm.nih.gov/31777301","citation_count":2,"is_preprint":false},{"pmid":"28298655","id":"PMC_28298655","title":"Dual NEP/ECE inhibition improves endothelial function in mesenteric resistance arteries of 32-week-old SHR.","date":"2017","source":"Hypertension research : official journal of the Japanese Society of Hypertension","url":"https://pubmed.ncbi.nlm.nih.gov/28298655","citation_count":2,"is_preprint":false},{"pmid":"9450558","id":"PMC_9450558","title":"[Phe21]big endothelin-1(18-34) and [Ala31]big endothelin-1(18-34) inhibit the human endothelin-converting enzyme-1 (ECE-1) expressed in CHO-K1 cells in a different fashion.","date":"1997","source":"FEBS letters","url":"https://pubmed.ncbi.nlm.nih.gov/9450558","citation_count":2,"is_preprint":false},{"pmid":"37271044","id":"PMC_37271044","title":"Mutation analysis of the ECE1 gene in late-onset Alzheimer's disease.","date":"2023","source":"Neurobiology of aging","url":"https://pubmed.ncbi.nlm.nih.gov/37271044","citation_count":1,"is_preprint":false},{"pmid":"36619519","id":"PMC_36619519","title":"Susceptibility of ECE1 polymorphisms to Hirschsprung's disease in southern Chinese children.","date":"2022","source":"Frontiers in pediatrics","url":"https://pubmed.ncbi.nlm.nih.gov/36619519","citation_count":1,"is_preprint":false},{"pmid":"40959779","id":"PMC_40959779","title":"ECE vs DISP Mechanisms in Anodic Electrolysis of Benzyl Alcohols: Computational Prediction of Microscopic Rate Constants.","date":"2025","source":"The journal of physical chemistry. C, Nanomaterials and interfaces","url":"https://pubmed.ncbi.nlm.nih.gov/40959779","citation_count":1,"is_preprint":false},{"pmid":"39062013","id":"PMC_39062013","title":"The Analysis of ECE1 and PPARG Variants in the Development of Osteopenia and Osteoporosis in Postmenopausal Women.","date":"2024","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/39062013","citation_count":0,"is_preprint":false},{"pmid":"22245098","id":"PMC_22245098","title":"In-silico characterization of ECE-1 inhibitors.","date":"2012","source":"Computers in biology and medicine","url":"https://pubmed.ncbi.nlm.nih.gov/22245098","citation_count":0,"is_preprint":false},{"pmid":"40951441","id":"PMC_40951441","title":"High-fat diet-induced dyslipidemia drives retinal ECE-1 and ET-1 upregulation.","date":"2025","source":"Frontiers in endocrinology","url":"https://pubmed.ncbi.nlm.nih.gov/40951441","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":50059,"output_tokens":7818,"usd":0.133723,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":17388,"output_tokens":3738,"usd":0.090195,"stage2_stop_reason":"end_turn"},"total_usd":0.223918,"stage1_batch_id":"msgbatch_01AsR7g8dGTEiEw9U83bJeWn","stage2_batch_id":"msgbatch_01YV5ZyxtFNUZEjxRcpd9jzb","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1994,\n      \"finding\": \"ECE-1 is a membrane-bound neutral metalloprotease that catalyzes the proteolytic conversion of big endothelin-1 (38-residue) to active endothelin-1 (21-residue) by cleavage at Trp21-Val22. Transfection of ECE-1 cDNA into cultured cells conferred the ability to secrete mature ET-1, and ECE-1 interacts with big ET-1 at the cell surface.\",\n      \"method\": \"cDNA transfection into cultured cells, functional secretion assay, cell-surface interaction assay\",\n      \"journal\": \"Cell\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct functional reconstitution in transfected cells with clear substrate-product conversion; foundational paper replicated by multiple subsequent labs\",\n      \"pmids\": [\"8062389\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1994,\n      \"finding\": \"ECE-1 is a zinc metalloprotease containing the HEXXH (HELTH) catalytic motif. Purified bovine ECE-1 was confirmed by peptide sequencing and the recombinant human enzyme has the same catalytic activity as the native enzyme.\",\n      \"method\": \"Enzyme purification, tryptic peptide sequencing, heterologous expression in cultured cells and Xenopus oocytes, activity assay\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — direct biochemical purification, active-site motif identification, and reconstituted recombinant activity\",\n      \"pmids\": [\"7805846\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ECE-1 exists as three isoforms (ECE-1a, ECE-1b, ECE-1c) generated from a single gene via alternative promoters, differing only in their N-terminal cytoplasmic tails. ECE-1a and ECE-1c localize to the cell surface, whereas ECE-1b localizes intracellularly with significant co-localization with the trans-Golgi network marker. All three isoforms have similar kinetic constants (Km, kcat, Vmax) for processing big endothelin-1, -2, and -3.\",\n      \"method\": \"Molecular cloning, immunofluorescence microscopy, subcellular localization, kinetic enzyme assays\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1–2 / Strong — direct subcellular localization by immunofluorescence tied to functional isoform characterization; kinetic assays performed for all isoforms\",\n      \"pmids\": [\"9396733\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Two di-leucine-based motifs in the N-terminal cytoplasmic tail of ECE-1b are responsible for its intracellular localization. One motif (LL) is unique to ECE-1b and responsible for its exclusive intracellular retention; a second motif (LV) is shared with ECE-1c and accounts for ECE-1c's reduced cell-surface expression relative to ECE-1a. Mutation of both motifs causes strong cell-surface appearance of ECE-1b.\",\n      \"method\": \"Chimeric protein construction, point mutagenesis, electron microscopy immunocytochemistry in CHO cells\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — site-directed mutagenesis with functional subcellular localization readout; single lab but multiple orthogonal methods (EM immunocytochemistry + chimeric proteins + mutagenesis)\",\n      \"pmids\": [\"10462527\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"A nine amino-acid segment in the cytosolic tail of ECE-1b containing two leucine residues is sufficient to redirect neprilysin (NEP) from the cell surface to an intracellular compartment, establishing this segment as an autonomous intracellular retention/targeting signal.\",\n      \"method\": \"ECE/NEP chimeric protein construction, transfection in MDCK cells, site-directed mutagenesis, subcellular localization\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — domain-swap chimera with mutagenesis identifies minimal targeting signal; single lab with two orthogonal methods\",\n      \"pmids\": [\"10377252\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1998,\n      \"finding\": \"ECE-1b localizes to early and late endosomes (not cell surface) in polarized MDCK cells. Phosphoramidon treatment increases ECE-1b protein level by slowing its lysosomal degradation (half-life extended from 2.8 h to 7.5 h), without changing mRNA levels, indicating rapid turnover of ECE-1b through endosomal-lysosomal compartments.\",\n      \"method\": \"Cell-surface biotinylation, immunofluorescence, anti-Rab5/Rab7 co-localization, pulse-chase immunoprecipitation, Western blot, Northern blot, confocal microscopy\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (pulse-chase, compartment marker co-localization, pharmacological inhibition) in single lab\",\n      \"pmids\": [\"9657986\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"A fourth isoform, ECE-1d, is generated from an additional promoter upstream of the third exon of the ECE-1 gene. ECE-1d has comparable converting activity to the other isoforms and is expressed at the cell surface, though less strongly than ECE-1a.\",\n      \"method\": \"Molecular cloning, promoter mapping, functional expression assay, cell-surface localization\",\n      \"journal\": \"European journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — single lab, cloning and functional expression with surface localization but limited mechanistic depth\",\n      \"pmids\": [\"10491078\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Genetic epistasis analysis using ECE-1/ECE-2 double-knockout mice showed that ECE-2 contributes to cardiac outflow and atrioventricular valve development redundantly with ECE-1, but significant residual ET-1/ET-2 remained in double-null embryos, indicating that additional proteases distinct from ECE-1 and ECE-2 can activate ET-1 in vivo.\",\n      \"method\": \"Homologous recombination knockout mice, compound mutant analysis, ET-1/ET-2 peptide measurement\",\n      \"journal\": \"The Journal of clinical investigation\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — genetic epistasis with double-KO mice, quantitative ET-1/ET-2 measurement; independently generated null alleles\",\n      \"pmids\": [\"10811845\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"ECE-1 (Ece1) and Tbx1 define distinct, non-interacting pathways in aortic arch morphogenesis. Ece1 is required for regression of cranial arch arteries and growth of caudal arch arteries (linked to endothelin-1 pathway neural crest function), whereas Tbx1 is required for early formation and growth of pharyngeal arch arteries. Compound Ece1/Tbx1 mutants showed no genetic interaction.\",\n      \"method\": \"Genetic epistasis in compound mutant mice, morphological analysis of pharyngeal arch artery remodeling\",\n      \"journal\": \"Developmental dynamics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean genetic epistasis with compound mutants, single lab, two-gene analysis\",\n      \"pmids\": [\"12950083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"The homeobox transcription factor Nkx2-5 activates all three ECE-1 isoform promoters (ECE-1a, ECE-1b, ECE-1c) in cardiomyoblasts. The ECE-1b promoter contains an Nkx2-5 consensus site required for direct activation; ECE-1a and ECE-1c promoters are activated indirectly. Stable Nkx2-5 overexpression increases ECE-1 isoform mRNA levels.\",\n      \"method\": \"Transient transfection reporter assays, gel shift assays (EMSA), site-directed mutagenesis of promoter elements, stable overexpression with RNase protection assay, Northern blot, real-time PCR\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — EMSA plus reporter mutagenesis plus stable overexpression; single lab with multiple methods\",\n      \"pmids\": [\"12824294\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"The ECE-1 gene is organized into 19 exons spanning >68 kb, mapped to chromosome 1p36. Two isoform mRNAs (ECE-1a and ECE-1b) are transcribed from two distinct promoters with different tissue distributions.\",\n      \"method\": \"Genomic cloning, exon-intron mapping, FISH chromosomal localization, tissue distribution analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct genomic structural analysis with chromosomal mapping; single lab\",\n      \"pmids\": [\"8530372\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"The ECE-1c promoter contains two positive regulatory regions (-142/-240 and -240/-490) likely binding GATA and ETS transcription factors, multiple transcriptional start sites (~-110, -140, and -350 bp), and a crucial E2F cis-element required for basal ECE-1c promoter activity as demonstrated by site-directed mutagenesis.\",\n      \"method\": \"Reporter gene assays with serial deletion mutants, transfection into endothelial and epithelial cells, site-directed mutagenesis, RNase protection assay, 5'-RACE\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — mutagenesis of promoter elements in multiple cell lines; single lab with several orthogonal methods\",\n      \"pmids\": [\"10682850\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"An arterial-specific enhancer in the human ECE1 locus is cooperatively activated by the transcription factors Sox17, FoxC2, and Etv2 through a conserved FOX:ETS composite motif and a SOX binding site. In transgenic mice, enhancer activity is restricted to arterial endothelium and endocardium by embryonic day 9.5.\",\n      \"method\": \"Transgenic mouse reporter assays, in vivo enhancer activity analysis, transcription factor binding site mutagenesis\",\n      \"journal\": \"Developmental biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vivo transgenic reporter with mutagenesis of binding sites; single lab\",\n      \"pmids\": [\"25179465\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"The TIMAP-protein phosphatase 1 (PP1c) complex physically interacts with ECE-1 and dephosphorylates it. PKC phosphorylates ECE-1, increasing its plasma membrane level and ET-1 secretion; TIMAP depletion reduces PP1c activity toward ECE-1, leading to elevated ECE-1 membrane abundance and elevated ET-1 production. Thus, PKC-phosphorylated ECE-1 is a TIMAP-PP1c substrate.\",\n      \"method\": \"Co-immunoprecipitation (protein-protein interaction), TIMAP siRNA knockdown, PKC activation, Western blot membrane fractionation, ET-1 secretion assay\",\n      \"journal\": \"The international journal of biochemistry & cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2–3 / Moderate — reciprocal co-IP showing TIMAP-PP1c-ECE1 complex, pharmacological and genetic perturbation with functional readout; single lab\",\n      \"pmids\": [\"26806547\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"siRNA-mediated knockdown of ECE-1 in prostate cancer stromal or epithelial cells reduces PC-3 epithelial cell invasion and migration. Re-addition of ET-1 only partially recovers invasion, indicating both ET-1-dependent and ET-1-independent functions for ECE-1. ECE-1 inhibition reduces focal adhesion kinase (FAK) phosphorylation; conversely, ECE-1 overexpression increases FAK phosphorylation, linking ECE-1 to FAK-mediated invasion signaling.\",\n      \"method\": \"siRNA/shRNA knockdown, Matrigel invasion assay, ET-1 rescue experiment, ECE-1 specific inhibitor treatment, Western blot for FAK phosphorylation, transient overexpression\",\n      \"journal\": \"British journal of cancer / Canadian journal of physiology and pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — siRNA knockdown and overexpression with pathway readout (FAK phosphorylation); two publications from same lab with consistent findings\",\n      \"pmids\": [\"18781169\", \"20725143\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ECE-1c and ECE-1a isoforms have opposing effects on prostate cancer cell invasion: ECE-1c overexpression increases PC-3 invasiveness through Matrigel, whereas ECE-1a expression suppresses invasion. Transient ECE-1a expression in stromal cells counteracts the pro-invasive effect of ECE-1c in epithelial cells.\",\n      \"method\": \"Transient isoform-specific overexpression, siRNA knockdown, Matrigel invasion assay, co-culture experiments\",\n      \"journal\": \"British journal of cancer\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — isoform-specific overexpression and knockdown with functional invasion readout; single lab\",\n      \"pmids\": [\"18781169\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"ECE-1 expression is post-transcriptionally regulated by alternative polyadenylation (APA). The ECE-1 3'UTR markedly inhibits protein expression, and APA produces transcripts with truncated 3'UTRs that promote elevated ECE-1 protein expression. Abolition of APA sites in a reporter construct reduced protein expression in prostate cancer cells.\",\n      \"method\": \"Reporter assay with 3'UTR constructs, APA site mutagenesis, comparison of 3'UTR length variants\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — reporter assay with mutagenesis of APA sites; single lab, single method approach\",\n      \"pmids\": [\"24497914\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"R-568 (calcimimetic) inhibits ECE-1 enzymatic activity by expelling zinc from the enzyme's active site, as demonstrated by restoration of activity upon addition of exogenous zinc and reduced zinc content in immunoprecipitated ECE-1 from R-568-treated cells. This results in decreased ET-1 synthesis despite increased ECE-1 protein levels.\",\n      \"method\": \"ECE-1 activity assay, zinc supplementation rescue experiment, immunoprecipitation with zinc measurement, Western blot, ELISA for ET-1\",\n      \"journal\": \"Pharmacological research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct mechanistic demonstration of zinc ejection from active site with functional and biochemical rescue; single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23911580\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"ECE-1 physically interacts with the pleckstrin homology (PH) domain of AKT and facilitates AKT translocation to the plasma membrane for activation, promoting lung cancer cell proliferation independent of its canonical ET-1 producing function. ECE-1 knockdown reduces AKT activation and tumor growth; AKT inhibition counteracts the growth-inhibitory effect of ECE-1 knockdown.\",\n      \"method\": \"Co-immunoprecipitation, immunofluorescence co-localization, RNA sequencing, ECE-1 knockdown (siRNA/shRNA), AKT inhibitor rescue, in vitro and xenograft tumor growth assays\",\n      \"journal\": \"The journal of gene medicine\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — co-IP demonstrating ECE1-AKT PH domain interaction, functional rescue with AKT inhibitor, in vivo xenograft validation; single lab\",\n      \"pmids\": [\"37897251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"Antisense oligodeoxynucleotide knockdown of ECE-1c in bovine pulmonary artery smooth muscle cells markedly reduced ECE-1c mRNA and ECE-1 protein, but basal and TNFα-stimulated ET-1 release were largely unaffected, indicating that an endopeptidase distinct from ECE-1 is mainly responsible for big ET-1 processing in VSMC.\",\n      \"method\": \"Antisense oligodeoxynucleotide treatment, RT-PCR, Western blot, ET-1 ELISA\",\n      \"journal\": \"Molecular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — antisense knockdown with protein-level confirmation and functional ET-1 readout; negative result is mechanistically informative; single lab\",\n      \"pmids\": [\"11160849\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ECE activity in human vascular smooth muscle (endothelium-denuded umbilical vein) is phosphoramidon-sensitive and can convert big ET-1, big ET-2(1-37), big ET-2(1-38), and big ET-3 to their mature biologically active forms, demonstrating broader substrate specificity than ET-1 alone.\",\n      \"method\": \"Pharmacological inhibition with phosphoramidon, functional vasoconstriction assay, radioimmunoassay for ET immunoreactivity\",\n      \"journal\": \"British journal of pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — functional ex vivo preparation with pharmacological inhibition; demonstrates substrate breadth; single lab\",\n      \"pmids\": [\"9422810\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"ECE-1 inhibition reduces ET-1 expression and cell invasiveness in MCF-7 breast cancer cells (54.3% of controls) using the selective ECE-1 inhibitor RO 67-7447.\",\n      \"method\": \"Selective ECE-1 inhibitor treatment, ET-1 expression assay, cell invasion assay\",\n      \"journal\": \"Breast cancer research and treatment\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pharmacological inhibitor study with functional invasion readout but no direct mechanistic pathway placement; single lab, single method type\",\n      \"pmids\": [\"17295044\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"siRNA-mediated knockdown of ECE-1 in oral squamous cell carcinoma (SCC) cells reduces SCC cell proliferation. ET-1 alone stimulates proliferation of oral SCC cells, and this is blocked by antagonists of either ETA or ETB receptors.\",\n      \"method\": \"siRNA knockdown, ECE-specific inhibitor, cell proliferation assay, receptor antagonist experiments\",\n      \"journal\": \"International journal of cancer\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — siRNA knockdown with proliferation readout; pathway placement via ET-1 and receptor antagonists; single lab\",\n      \"pmids\": [\"16217751\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ECE-1 has an ectodomain structurally related to neutral endopeptidase 24.11 (NEP), and is a type II integral membrane protein expressed predominantly in endothelial cells. Multiple isoforms (ECE-1a, ECE-1b, ECE-1c, and ECE-2) exist with different characteristics.\",\n      \"method\": \"Sequence analysis, comparative biochemistry, structural homology analysis\",\n      \"journal\": \"FASEB journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Strong — review synthesizing experimental findings from multiple labs; structural homology confirmed by protein biochemistry\",\n      \"pmids\": [\"9141502\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ERK signaling pathway activation in hepatic stellate cells (after bile duct ligation) regulates ECE-1 expression: inhibition of ERK in stellate cells from BDL-injured liver leads to decreased ECE-1 expression, linking TGF-β/ERK signaling to ECE-1 transcriptional regulation in liver fibrosis.\",\n      \"method\": \"Pharmacological ERK inhibition, qRT-PCR for ECE-1, stellate cell isolation, phospho-Smad3 and MAP kinase Western blot\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — pharmacological pathway inhibition with mRNA readout; single lab, limited mechanistic detail in abstract\",\n      \"pmids\": [\"18753413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2008,\n      \"finding\": \"ECE protein is expressed in the embryonic chick heart in endothelial cells, mesenchymal cells, myocytes, and is enriched in trabeculae and nascent ventricular conduction system. ET receptor blockade with bosentan delayed activation sequence maturation, and hemodynamic loading modifies myocardial ECE expression, supporting a role for ECE in cardiac conduction system differentiation.\",\n      \"method\": \"Immunohistochemistry with custom antibody, in vivo ET receptor blockade (bosentan), experimental hemodynamic loading, Western blot\",\n      \"journal\": \"Developmental dynamics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct localization by IHC plus pharmacological perturbation with functional conduction readout; single lab in avian model\",\n      \"pmids\": [\"18489007\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Tspan8 (tetraspanin) physically associates with ECE-1 and amplifies its activity in converting big ET-1 to ET-1, as demonstrated in colon carcinoma cells transduced with Tspan8 and in ileum tissue from tspan8 knockout mice versus wild-type mice.\",\n      \"method\": \"Mass spectrometry, Western blot co-immunoprecipitation, Tspan8 transduction in Isreco1 cells, tspan8 knockout mouse tissue analysis, ECE-1 activity assay\",\n      \"journal\": \"Cancers\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — MS identification of complex confirmed by co-IP with functional activity assay in both cell model and KO mouse tissue; single lab\",\n      \"pmids\": [\"37835445\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"ECE-1 knockout mice show reduced kidney fibrosis, tubular injury, macrophage infiltration, fibroblast number, and myofibroblast formation after unilateral ureteral obstruction, associated with reduced TGF-β1 and α-SMA protein levels, demonstrating that ECE-1-mediated ET-1 activation drives pro-fibrotic signaling in the kidney.\",\n      \"method\": \"ECE-1 knockout mice, unilateral ureteral obstruction model, histopathology, immunostaining (F4/80, FSP-1, α-SMA), qRT-PCR, Western blot\",\n      \"journal\": \"Life sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — clean KO with defined cellular phenotypes and molecular pathway readouts; single lab\",\n      \"pmids\": [\"32768584\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"Phosphoramidon differentially affects ECE-1 isoforms: it increases intracellular ECE-1a and ECE-1b protein levels by prolonging their half-lives (via inhibition of intracellular degradation) but does not affect ECE-1c protein levels. mRNA levels are unchanged, indicating post-translational regulation.\",\n      \"method\": \"Metabolic pulse-chase labeling, immunoprecipitation, Western blot, Northern blot, immunocytochemistry in CHO cell lines stably expressing individual ECE-1 isoforms\",\n      \"journal\": \"Journal of cardiovascular pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — pulse-chase with immunoprecipitation directly measuring half-lives; single lab, multiple isoforms tested\",\n      \"pmids\": [\"12827039\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ECE-1 in endothelial cells (EA.hy926) is an integral membrane protein, as demonstrated by detergent solubilization and temperature-induced phase separation. Greater than 75% of total ECE activity could be immunoprecipitated with a monoclonal antibody raised against neutral endopeptidase E-24.11, indicating a shared epitope between ECE and NEP.\",\n      \"method\": \"Detergent phase separation, antibody immunoprecipitation of enzymatic activity\",\n      \"journal\": \"Journal of cardiovascular pharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — biochemical fractionation and antibody cross-reactivity; single method, single lab\",\n      \"pmids\": [\"8587468\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"ECE-1 inhibition by phosphoramidon in big ET-1-stimulated human umbilical vein smooth muscle preparations blocks vasoconstriction in a concentration-dependent manner, confirming that smooth muscle ECE converts big ET-1 to active ET-1 via a phosphoramidon-sensitive mechanism.\",\n      \"method\": \"Ex vivo vascular preparation, phosphoramidon pharmacological inhibition, concentration-response analysis\",\n      \"journal\": \"British journal of pharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — functional pharmacological inhibition in ex vivo preparation; single lab, indirect enzymatic evidence\",\n      \"pmids\": [\"9422810\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1997,\n      \"finding\": \"Big ET-1 peptide analogues [Phe21]big ET-1(18-34) and [Ala31]big ET-1(18-34) inhibit ECE-1 activity in different fashions: [Phe21]big ET-1(18-34) is a competitive inhibitor (Ki=20.6 µM) and [Ala31]big ET-1(18-34) is a noncompetitive inhibitor (Ki=35.6 µM), indicating ECE-1 recognizes big ET-1 both at the P1 position and at the C-terminal region through distinct mechanisms.\",\n      \"method\": \"Kinetic analysis of ECE-1 inhibition using solubilized membranes from ECE-1-expressing CHO-K1 cells, competitive vs. noncompetitive inhibitor determination\",\n      \"journal\": \"FEBS letters\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — direct enzyme kinetics with mechanistic interpretation; single lab, single method\",\n      \"pmids\": [\"9450558\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ECE-1 is a zinc-dependent, type II integral membrane metalloprotease (HEXXH motif) that catalyzes the final, rate-limiting cleavage of big endothelin-1 at Trp21-Val22 to generate the potent vasoconstrictor ET-1; it exists as four isoforms (a–d) generated by alternative promoters, whose distinct N-terminal di-leucine motifs determine differential subcellular localization (cell surface for ECE-1a/c/d, trans-Golgi/endosomal-lysosomal pathway for ECE-1b), and whose activity is regulated post-translationally by PKC phosphorylation/TIMAP-PP1c dephosphorylation, by zinc chelation (calcimimetics), and by the tetraspanin Tspan8 (which amplifies activity); beyond ET-1 production, ECE-1 also promotes cell invasion and proliferation through ET-1-independent mechanisms including direct interaction with the AKT pleckstrin homology domain to facilitate membrane translocation and AKT activation.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"ECE-1 is a zinc-dependent, type II integral membrane metalloprotease that catalyzes the final, rate-limiting step in endothelin biosynthesis, cleaving big endothelin-1 at Trp21-Val22 to generate the active vasoconstrictor ET-1 [#0, #1]. Catalysis depends on a HEXXH (HELTH) zinc-binding active site, and the enzyme converts big ET-1, -2, and -3, with substrate recognition occurring at both the P1 scissile position and the C-terminal region of big ET-1 [#1, #20, #31]. A single gene on chromosome 1p36 produces four isoforms (a–d) from alternative promoters that share catalytic activity but differ only in their N-terminal cytoplasmic tails; di-leucine-based motifs in these tails act as autonomous targeting signals that route ECE-1b to intracellular endosomal-lysosomal compartments while ECE-1a, -1c, and -1d reach the cell surface [#2, #3, #4, #5, #6, #10]. ECE-1 abundance and activity are controlled post-translationally: isoform half-lives are set by intracellular degradation [#5, #28], PKC phosphorylation increases plasma-membrane ECE-1 and ET-1 secretion while the TIMAP-PP1c phosphatase complex reverses this [#13], the calcimimetic R-568 inhibits the enzyme by ejecting active-site zinc [#17], and the tetraspanin Tspan8 physically associates with ECE-1 to amplify big ET-1 conversion [#26]. Transcription of the isoform promoters is driven by cardiac and vascular regulators including Nkx2-5 and an arterial endothelial enhancer cooperatively bound by Sox17, FoxC2, and Etv2 [#9, #11, #12]. In vivo, ECE-1 acts redundantly with ECE-2 in cardiac outflow and aortic arch artery remodeling, with residual ET activation indicating additional non-ECE proteases, and ECE-1-mediated ET-1 production drives pro-fibrotic signaling in the kidney [#7, #8, #27]. Beyond ET-1 generation, ECE-1 promotes cancer cell invasion and proliferation through both ET-1-dependent and ET-1-independent routes, including modulation of FAK phosphorylation and direct interaction with the AKT pleckstrin homology domain to facilitate AKT membrane translocation and activation [#14, #15, #18].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Established the core identity and function of ECE-1: that a single membrane metalloprotease executes the rate-limiting conversion of big ET-1 to mature ET-1, the molecular basis of endothelin production.\",\n      \"evidence\": \"cDNA transfection with functional ET-1 secretion assay; enzyme purification, peptide sequencing, and recombinant activity reconstitution identifying the HEXXH zinc motif\",\n      \"pmids\": [\"8062389\", \"7805846\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Cleavage at Trp21-Val22 defined for ET-1 but full substrate scope not yet mapped\", \"No structural model of the catalytic ectodomain\"]\n    },\n    {\n      \"year\": 1997,\n      \"claim\": \"Defined the gene architecture and isoform diversity, showing multiple promoters generate catalytically equivalent isoforms differing only in N-terminal tails — the basis for differential localization despite shared enzymology.\",\n      \"evidence\": \"Genomic cloning, FISH mapping, molecular cloning, immunofluorescence, and kinetic enzyme assays across isoforms in cultured cells\",\n      \"pmids\": [\"8530372\", \"9396733\", \"9141502\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Why distinct subcellular pools are needed for an enzyme with one substrate not resolved\", \"Tissue-specific isoform usage only partly characterized\"]\n    },\n    {\n      \"year\": 1999,\n      \"claim\": \"Identified the molecular targeting signals that route ECE-1b intracellularly, showing di-leucine motifs are autonomous retention signals sufficient to redirect even a heterologous protease.\",\n      \"evidence\": \"Chimeric protein and ECE/NEP domain-swap construction, point mutagenesis, and EM immunocytochemistry in CHO and MDCK cells; identification of a fourth isoform ECE-1d\",\n      \"pmids\": [\"10462527\", \"10377252\", \"10491078\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Adaptor proteins reading the di-leucine motifs not identified\", \"Functional consequence of intracellular versus surface processing pools unclear\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Tested ECE-1 sufficiency in vivo through genetics, revealing redundancy with ECE-2 and the existence of additional ET-activating proteases — refining ECE-1 from sole to principal converting enzyme.\",\n      \"evidence\": \"ECE-1/ECE-2 double-knockout mice with quantitative ET-1/ET-2 peptide measurement; antisense knockdown in pulmonary artery smooth muscle cells\",\n      \"pmids\": [\"10811845\", \"11160849\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the residual non-ECE ET-converting protease(s) unknown\", \"Cell-type-specific reliance on ECE-1 versus alternatives unmapped\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Connected ECE-1 to developmental morphogenesis and its transcriptional control, placing the gene within endothelin-pathway neural crest function and cardiac regulatory networks.\",\n      \"evidence\": \"Compound mutant mouse epistasis for aortic arch remodeling; EMSA, reporter mutagenesis, and overexpression linking Nkx2-5 to isoform promoters; enzyme kinetics defining big ET-1 recognition\",\n      \"pmids\": [\"12950083\", \"12824294\", \"9450558\", \"12827039\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct downstream developmental targets of ECE-1-generated ET-1 not defined\", \"Promoter regulation studied largely in cell lines\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Resolved multilayered control of ECE-1 expression — an arterial endothelial enhancer and post-transcriptional 3'UTR/alternative polyadenylation regulation tuning protein output.\",\n      \"evidence\": \"Transgenic mouse enhancer reporter with Sox17/FoxC2/Etv2 binding-site mutagenesis; 3'UTR reporter assays with APA-site mutagenesis in prostate cancer cells\",\n      \"pmids\": [\"25179465\", \"24497914\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Whether APA regulation operates in vascular tissue not shown\", \"trans-factors controlling APA choice unidentified\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Defined post-translational regulation of ECE-1 surface abundance through a phosphorylation cycle, identifying a specific kinase and phosphatase complex acting on the enzyme.\",\n      \"evidence\": \"Reciprocal co-IP for TIMAP-PP1c-ECE-1, TIMAP siRNA, PKC activation, membrane fractionation, and ET-1 secretion assays\",\n      \"pmids\": [\"26806547\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Phosphorylation sites on ECE-1 not mapped\", \"Which isoforms are PKC substrates not resolved\", \"Single lab, no reciprocal phosphatase validation in vivo\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Extended ECE-1 function beyond proteolysis, demonstrating activity amplification by a tetraspanin partner and an ET-1-independent scaffolding role in promoting AKT activation and tumor growth.\",\n      \"evidence\": \"Mass spectrometry and co-IP for Tspan8 association with KO mouse validation; co-IP/co-localization mapping ECE-1 to the AKT PH domain with AKT-inhibitor rescue and xenograft assays\",\n      \"pmids\": [\"37835445\", \"37897251\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of the ECE-1–AKT PH domain interaction unknown\", \"Whether the AKT-promoting role requires catalytic activity not tested\", \"Mechanism by which Tspan8 amplifies activity unresolved\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"It remains unknown how ECE-1's distinct subcellular pools and isoform-specific functions are integrated, and whether its non-catalytic AKT-scaffolding activity operates in normal physiology beyond cancer.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No high-resolution structure of full-length ECE-1 or its complexes\", \"Identity of residual ET-converting proteases unresolved\", \"Catalytic versus scaffolding contributions to disease phenotypes not separated\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0140096\", \"supporting_discovery_ids\": [0, 1, 2, 20, 31]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"GO:0008237\", \"supporting_discovery_ids\": [1]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [0, 2, 3, 6, 29]},\n      {\"term_id\": \"GO:0005794\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005768\", \"supporting_discovery_ids\": [5]},\n      {\"term_id\": \"GO:0005764\", \"supporting_discovery_ids\": [5, 28]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [0, 13, 18]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [7, 8, 12, 25]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [0, 1]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [14, 18, 27]}\n    ],\n    \"complexes\": [\"TIMAP-PP1c-ECE-1 complex\"],\n    \"partners\": [\"AKT1\", \"TIMAP\", \"PPP1CA\", \"TSPAN8\", \"ECE2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"faith_supported":7,"faith_total":7,"faith_pct":100.0}}