{"gene":"ALOX15B","run_date":"2026-04-28T17:12:37","timeline":{"discoveries":[{"year":1999,"finding":"Human 15-LOX-2 (ALOX15B) catalyzes the oxygenation of arachidonic acid to 15S-HETE as its major product; this activity was demonstrated in benign prostate tissue incubated with [14C]arachidonic acid, with 15-HETE confirmed as the dominant metabolite by HPLC.","method":"Radiolabeled substrate incubation with tissue, reverse- and straight-phase HPLC product identification; immunohistochemistry for localization","journal":"The American journal of pathology","confidence":"High","confidence_rationale":"Tier 1 — direct enzymatic product identification in tissue, replicated in multiple specimens, foundational paper with >100 citations","pmids":["10393855"],"is_preprint":false},{"year":2016,"finding":"Human ALOX15B generates a 15-S-hydroperoxy product from arachidonic acid while murine Alox15b generates an 8-S-product; both enzymes can oxygenate phospholipid-esterified arachidonic acid in a bilayer context (nanodiscs) to a 15-S-product. ALOX15B translocates to the plasma membrane upon Ca2+ ionophore stimulation, and this membrane localization is dependent on a putative membrane insertion loop.","method":"In vitro enzyme assays with nanodiscs as membrane mimics; transfected HEK293 cell imaging; site-directed mutagenesis of membrane insertion loop","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 — reconstitution with membrane mimics, mutagenesis, and live-cell localization with functional consequence in single rigorous study","pmids":["27435673"],"is_preprint":false},{"year":2023,"finding":"The distinct reaction specificities of human ALOX15B (15-hydroperoxy product) versus mouse Alox15b (8-hydroperoxy product) are determined by residues at positions 602-603 (Asp602/Val603 in human; Tyr603/His604 in mouse). Asp602Tyr+Val603His exchange in human ALOX15B murinized its product pattern, while Tyr603Asp+His604Val substitution in mouse Alox15b humanized it; in silico substrate docking supports an inverse substrate binding mechanism.","method":"Recombinant protein expression, in vitro enzyme activity assays with multiple polyunsaturated fatty acid substrates, active-site mutagenesis, molecular dynamics simulation and substrate docking","journal":"International journal of molecular sciences","confidence":"High","confidence_rationale":"Tier 1 — in vitro reconstitution with mutagenesis, multiple substrates, and computational validation confirming mechanism","pmids":["37373195"],"is_preprint":false},{"year":2011,"finding":"15-LOX-2 product 15(S)-HETE promotes proliferation of pulmonary artery smooth muscle cells (PASMCs) under hypoxia via ERK1/2 (MEK/ERK) phosphorylation; this proliferative effect is blocked by MEK inhibitors PD-98059 and U0126, and by 15-LOX inhibitors NDGA and CDC.","method":"Cultured rabbit PASMC proliferation assays, BrdU incorporation, Western blotting for ERK1/2 phosphorylation, pharmacological inhibitors","journal":"Prostaglandins, leukotrienes, and essential fatty acids","confidence":"Medium","confidence_rationale":"Tier 2 — defined cellular pathway via pharmacological epistasis with multiple inhibitors, single lab","pmids":["22018966"],"is_preprint":false},{"year":2015,"finding":"15-LOX-2/15-HETE signaling promotes pulmonary arterial smooth muscle cell (PASMC) proliferation, cell cycle progression, migration, and suppression of apoptosis under hypoxia through activation of ERK and p38 MAPK phosphorylation.","method":"TUNEL assay, flow cytometry, BrdU incorporation, Western blotting for p-ERK and p-p38MAPK in cultured PASMCs and PAH patient/rat lungs","journal":"Cellular physiology and biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 — multiple cellular readouts in vitro and human/animal tissue; pathway placement via downstream kinase analysis","pmids":["25895668"],"is_preprint":false},{"year":2023,"finding":"p53 activates ALOX15B lipoxygenase activity by suppressing SLC7A11 (cystine transporter), thereby inducing ferroptosis in bladder cancer cells; knockdown of ALOX15B protects bladder cancer cells from p53-induced ferroptosis.","method":"shRNA/oe-plasmid transfection, p53 agonist Nutlin-3a treatment, ferroptosis inhibitor ferrostatin-1, iron chelator deferoxamine, in vitro and in vivo tumor models","journal":"Laboratory investigation","confidence":"Medium","confidence_rationale":"Tier 2 — genetic epistasis (p53→SLC7A11→ALOX15B) with multiple pharmacological controls and in vivo validation","pmids":["36801644"],"is_preprint":false},{"year":2024,"finding":"ALOX15B controls macrophage cholesterol homeostasis through a lipid peroxidation→ERK1/2→SREBP2 axis: ALOX15B-mediated lipid peroxidation activates ERK1/2, which sustains nuclear SREBP2 abundance and activity, thereby regulating cholesterol biosynthetic gene expression and sterol intermediates (desmosterol, lathosterol, 25- and 27-hydroxycholesterol).","method":"siRNA silencing of ALOX15B in primary human macrophages, global transcriptome analysis, immunofluorescence, ERK1/2 inhibition, NPC1 inhibition, sterol quantification by mass spectrometry","journal":"Redox biology","confidence":"High","confidence_rationale":"Tier 2 — multiple orthogonal methods (transcriptomics, immunofluorescence, pharmacological epistasis, metabolite quantification) in primary human cells establishing pathway mechanism","pmids":["38581859"],"is_preprint":false},{"year":2025,"finding":"ALOX15B silencing in human epidermal keratinocytes augments inflammation by reducing EGFR expression, leading to enhanced JAK1/STAT1 signaling and increased CCL2, CCL5, and CXCL10 secretion; reduced ERK phosphorylation downstream of EGFR also decreases cholesterol biosynthesis gene expression and depletes plasma membrane cholesterol/lipid rafts.","method":"siRNA knockdown, lipoxygenase inhibitor ML351, JAK1/STAT1 pathway inhibition, EGFR inhibition, confocal microscopy for membrane lipids, cytokine quantification, skin equivalents","journal":"Cell death & disease","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal approaches (siRNA, pharmacological inhibition, live imaging) linking ALOX15B to EGFR/JAK1/STAT1 pathway in human keratinocytes","pmids":["39843435"],"is_preprint":false},{"year":2025,"finding":"In pancreatic cancer, KRAS-mutant/ERK1-driven phosphorylation of ABHD17C promotes depalmitoylation of ALOX15B and its translocation from the plasma membrane to the cytoplasm, leading to proteasome-dependent degradation via the CUL4/DDB1/DCAF10 E3 ligase complex; restoration of S-palmitoylation by methyl protodioscin (which disrupts ABHD17C/ALOX15B interaction) re-localizes ALOX15B to the membrane and induces ferroptosis.","method":"Co-IP (ABHD17C–ALOX15B interaction), palmitoylation assays, proteasome inhibition, subcellular fractionation, patient-derived organoids, in vivo tumor models","journal":"Advanced science","confidence":"High","confidence_rationale":"Tier 1-2 — identifies PTM (S-palmitoylation/depalmitoylation), E3 ligase complex, binding partner, and subcellular localization with functional consequence in vitro and in vivo","pmids":["40569151"],"is_preprint":false},{"year":2022,"finding":"In porcine Sertoli cells under heat stress, ALOX15B expression is upregulated and increases 8-HETE and 15-HETE levels, activating the p38-p53 pathway to promote apoptosis; p38 inhibition reduces ALOX15B expression, and p38/p53 feedback regulates ALOX15B and lipid peroxide levels.","method":"Metabolomics (LC-MS), siRNA knockdown, ALOX15B inhibitor baicalein, p38 inhibitor, p53 inhibitor, apoptosis assays","journal":"Theriogenology","confidence":"Medium","confidence_rationale":"Tier 2 — multiple pharmacological and genetic approaches establishing a feedback loop between ALOX15B activity and p38-p53 pathway in defined cellular model","pmids":["35344833"],"is_preprint":false},{"year":2022,"finding":"Humanization of mouse Alox15b reaction specificity (Tyr603Asp+His604Val knock-in) in vivo alters the plasma oxylipidome and leads to a gender-specific (male-only) premature growth arrest and impaired red blood cell parameters in aging mice, indicating that ALOX15B product specificity (15- vs 8-HETE) has distinct physiological consequences in the hematopoietic system.","method":"Knock-in mouse model, plasma oxylipidomics, hematological parameter measurement, body weight tracking","journal":"Biomedicines","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo genetic model with defined molecular change and quantitative physiological phenotype, single lab","pmids":["35740398"],"is_preprint":false},{"year":2023,"finding":"Humanization of mouse Alox15b reaction specificity (knock-in Tyr603Asp+His604Val) sensitizes female mice to dextran sodium sulfate-induced colitis (more weight loss, slower recovery) but partially protects in complete Freund's adjuvant-induced paw edema, demonstrating that the 15-hydroperoxy versus 8-hydroperoxy product balance of ALOX15B determines divergent pro- and anti-inflammatory outcomes in distinct disease contexts.","method":"Knock-in mouse models, DSS colitis model, CFA paw edema model, eicosanoid profiling, pain perception tests","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo genetic epistasis with two inflammation models and metabolite profiling, single lab","pmids":["37446212"],"is_preprint":false},{"year":2013,"finding":"Non-synonymous polymorphic variants of ALOX15B (p.Arg486His, p.Gln656Arg, p.Ile676Val) show similar enzyme activity and Michaelis-Menten kinetics to wild-type ALOX15B when expressed and assayed in vitro, indicating these common variants do not alter catalytic function.","method":"Recombinant protein expression, in vitro enzyme activity assays, Michaelis-Menten kinetics","journal":"Clinical biochemistry","confidence":"Medium","confidence_rationale":"Tier 1 — direct in vitro enzyme kinetics for multiple variants, but single lab and limited mechanistic follow-up","pmids":["24373925"],"is_preprint":false},{"year":2025,"finding":"IRF1 directly transcriptionally activates ALOX15B by binding its promoter, as shown by dual-luciferase reporter assays, EMSA, and ChIP-qPCR; IRF1-driven ALOX15B expression promotes ferroptosis in TNBC cells by inhibiting SLC7A11 and GPX4, reducing glutathione, and increasing lipid oxidation.","method":"Dual-luciferase reporter assays, EMSA, ChIP-qPCR, siRNA knockdown, ALOX15B overexpression, ferroptosis marker quantification","journal":"Biochimica et biophysica acta. General subjects","confidence":"Medium","confidence_rationale":"Tier 2 — multiple orthogonal methods (luciferase, EMSA, ChIP) confirming transcriptional regulation; functional consequence via ferroptosis assays","pmids":["40749811"],"is_preprint":false},{"year":2026,"finding":"ALOX15B deficiency in DLBCL cells leads to upregulation of COX-2/PGE2 signaling and downregulation of the TAP1/MHC-I antigen presentation axis, promoting immune evasion; HDAC1/2 occupy the ALOX15B promoter to repress its expression, and HDAC inhibitor tucidinostat restores ALOX15B expression and antigen presentation.","method":"siRNA knockdown, luciferase reporter assay, ChIP-seq, ATAC-seq, murine and PDX models, immunohistochemistry","journal":"Journal of experimental & clinical cancer research","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP-seq/ATAC-seq establish epigenetic mechanism; functional consequences validated in vivo, but single lab","pmids":["41527135"],"is_preprint":false},{"year":2025,"finding":"ALOX15B expression in pulmonary artery endothelial cells is elevated in PAH and promotes endothelial cell proliferation and vascular remodeling; ALOX15B knockdown reduces hypoxia-induced autophagy in mouse PAECs, an effect reversed by PI3K inhibitor, placing ALOX15B upstream of the PI3K/AKT/mTOR pathway in autophagy regulation.","method":"siRNA knockdown, PI3K inhibitor treatment, Western blot, right heart catheterization, echocardiography, mouse PAH models (hypoxia ± Sugen5416), systemic knockout mice","journal":"European journal of pharmacology","confidence":"Medium","confidence_rationale":"Tier 2 — genetic (KO mice) and siRNA approaches with pharmacological epistasis in vitro and in vivo, single lab","pmids":["41207352"],"is_preprint":false},{"year":2026,"finding":"CEBPA directly binds the ALOX15B promoter to transcriptionally activate it; the CEBPA/ALOX15B axis promotes ferroptosis in osteoblasts and contributes to bone loss in postmenopausal osteoporosis via the AMPK/mTOR pathway, as shown by ALOX15B knockout mice subjected to ovariectomy displaying attenuated bone loss and reduced ferroptosis markers.","method":"ChIP (CEBPA at ALOX15B promoter), siRNA/overexpression in hFOB 1.19 cells, AMPK/mTOR pathway inhibitors, ALOX15B knockout mouse OVX model, micro-CT, bone density analysis, ferroptosis marker assays","journal":"Inflammation research","confidence":"Medium","confidence_rationale":"Tier 2 — ChIP confirming direct transcriptional regulation, KO mouse model with in vivo phenotype, pharmacological pathway validation","pmids":["41843143"],"is_preprint":false}],"current_model":"ALOX15B is a non-heme iron dioxygenase that oxygenates arachidonic acid and other polyunsaturated fatty acids at the C-15 position (producing 15S-HpETE/15S-HETE) via a catalytic mechanism determined by active-site residues Asp602/Val603; it translocates to the plasma membrane upon Ca2+ stimulation in a membrane-insertion-loop-dependent manner and can oxygenate phospholipid-esterified substrates in bilayers. Its membrane localization is regulated by S-palmitoylation (removed by ABHD17C downstream of KRAS/ERK1), targeting ALOX15B for CUL4/DDB1/DCAF10-mediated proteasomal degradation. Its transcription is activated by IRF1 and CEBPA, and repressed epigenetically by HDAC1/2. Through lipid peroxidation, ALOX15B activates ERK1/2 to sustain SREBP2-driven cholesterol biosynthesis in macrophages, promotes PASMC proliferation via ERK/p38 MAPK, modulates keratinocyte inflammation through EGFR/JAK1/STAT1, and induces ferroptosis in cancer cells via a p53/SLC7A11-dependent mechanism, with its 15- versus 8-hydroperoxide product balance determining distinct pro- and anti-inflammatory outcomes in vivo."},"narrative":{"teleology":[{"year":1999,"claim":"Establishing that ALOX15B is a 15S-HETE-producing lipoxygenase resolved the identity and dominant product of this second human 15-lipoxygenase isoform.","evidence":"Radiolabeled arachidonic acid incubation with benign prostate tissue, HPLC product identification","pmids":["10393855"],"confidence":"High","gaps":["Catalytic mechanism and active-site determinants of positional specificity unknown","Subcellular localization dynamics not addressed","No structural information available"]},{"year":2011,"claim":"Linking the ALOX15B product 15(S)-HETE to PASMC proliferation via MEK/ERK1/2 placed the enzyme's lipid products within a defined mitogenic signaling cascade relevant to pulmonary vascular remodeling.","evidence":"BrdU incorporation, Western blot for p-ERK1/2, MEK inhibitors PD-98059 and U0126 in cultured rabbit PASMCs under hypoxia","pmids":["22018966","25895668"],"confidence":"Medium","gaps":["Direct target of 15-HETE upstream of ERK not identified","Pathway epistasis relies on pharmacological inhibitors without genetic confirmation in first study","Human PASMC data limited"]},{"year":2016,"claim":"Demonstrating Ca²⁺-dependent plasma membrane translocation, membrane insertion loop dependency, and oxygenation of phospholipid-esterified substrates in nanodiscs established ALOX15B as a membrane-acting enzyme, not merely a cytosolic lipid oxygenase.","evidence":"Nanodisc reconstitution, site-directed mutagenesis of membrane insertion loop, live-cell imaging in transfected HEK293 cells","pmids":["27435673"],"confidence":"High","gaps":["Structural basis of membrane insertion loop–bilayer interaction unresolved","Lipid preferences at the membrane not systematically characterized"]},{"year":2022,"claim":"Knock-in mice with humanized Alox15b product specificity revealed that the 15- versus 8-HETE product ratio has distinct in vivo physiological consequences including sex-specific hematopoietic and inflammatory phenotypes.","evidence":"Alox15b Tyr603Asp+His604Val knock-in mice, plasma oxylipidomics, hematological analysis, DSS colitis and CFA paw edema models","pmids":["35740398","37446212"],"confidence":"Medium","gaps":["Mechanistic targets of 15-HETE vs 8-HETE driving divergent inflammatory outcomes not identified","Basis of sex specificity unknown","Single lab generated both studies"]},{"year":2023,"claim":"Identifying Asp602/Val603 as the determinants of human ALOX15B 15-lipoxygenating specificity resolved the molecular basis for the species-specific product difference between human and mouse orthologs.","evidence":"Reciprocal active-site mutagenesis of recombinant human and mouse enzymes, in vitro assays with multiple PUFA substrates, molecular dynamics","pmids":["37373195"],"confidence":"High","gaps":["No crystal structure of ALOX15B to confirm docking predictions","Whether other active-site residues contribute to fine-tuning specificity untested"]},{"year":2023,"claim":"Placing ALOX15B downstream of p53 and upstream of ferroptosis via the SLC7A11/glutathione axis established a tumor-suppressive lipid peroxidation pathway in bladder cancer.","evidence":"shRNA knockdown, p53 agonist Nutlin-3a, ferrostatin-1 rescue, in vitro and xenograft tumor models","pmids":["36801644"],"confidence":"Medium","gaps":["Direct lipid peroxidation substrates driving ferroptosis not identified","Whether ALOX15B enzymatic activity or protein scaffold is required not dissected"]},{"year":2024,"claim":"Demonstrating that ALOX15B-mediated lipid peroxidation activates ERK1/2 to sustain nuclear SREBP2 and cholesterol biosynthesis in macrophages connected the enzyme to sterol metabolism and foam cell biology.","evidence":"siRNA in primary human macrophages, transcriptomics, ERK1/2 inhibition, sterol quantification by mass spectrometry","pmids":["38581859"],"confidence":"High","gaps":["Identity of the specific lipid peroxide species activating ERK1/2 unknown","In vivo atherosclerosis relevance not tested"]},{"year":2025,"claim":"Discovery that KRAS/ERK1-driven ABHD17C depalmitoylates ALOX15B, triggering CUL4/DDB1/DCAF10-mediated proteasomal degradation, revealed a complete post-translational regulatory circuit controlling ALOX15B stability and ferroptotic capacity in pancreatic cancer.","evidence":"Co-IP, palmitoylation assays, proteasome inhibition, subcellular fractionation, patient-derived organoids, in vivo tumor models","pmids":["40569151"],"confidence":"High","gaps":["Palmitoylation site(s) on ALOX15B not mapped","Whether this degradation pathway operates in non-cancer cells unknown"]},{"year":2025,"claim":"Identifying IRF1 and CEBPA as direct transcriptional activators of ALOX15B and HDAC1/2 as epigenetic repressors defined the transcriptional control layer governing ALOX15B expression across cancer, immune evasion, and bone homeostasis contexts.","evidence":"ChIP-qPCR/ChIP-seq, EMSA, dual-luciferase reporters, HDAC inhibitor treatment, ALOX15B KO mice with OVX","pmids":["40749811","41527135","41843143"],"confidence":"Medium","gaps":["Relative contributions of IRF1, CEBPA, and HDAC1/2 in the same cell type not compared","Whether additional transcription factors regulate tissue-specific expression unknown","Chromatin architecture at the ALOX15B locus not fully characterized"]},{"year":null,"claim":"Major unresolved questions include: the crystal structure of ALOX15B, the identity of specific lipid peroxide species that activate ERK1/2, the palmitoylation site(s), and how the enzyme's dual pro-inflammatory (15-HETE) and context-dependent anti-inflammatory roles are balanced in human disease.","evidence":"","pmids":[],"confidence":"High","gaps":["No solved 3D structure","Direct lipid peroxide mediator of ERK activation not identified","S-palmitoylation site(s) not mapped","In vivo human genetic evidence linking ALOX15B variants to disease absent"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016491","term_label":"oxidoreductase activity","supporting_discovery_ids":[0,1,2]},{"term_id":"GO:0008289","term_label":"lipid binding","supporting_discovery_ids":[1,8]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,8]},{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[8]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[0,1,2,6]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[3,4,6,7]},{"term_id":"R-HSA-5357801","term_label":"Programmed Cell Death","supporting_discovery_ids":[5,8,13,16]},{"term_id":"R-HSA-392499","term_label":"Metabolism of proteins","supporting_discovery_ids":[8]},{"term_id":"R-HSA-168256","term_label":"Immune System","supporting_discovery_ids":[14]}],"complexes":[],"partners":["ABHD17C","DCAF10","DDB1","CUL4A","IRF1","CEBPA","HDAC1","SLC7A11"],"other_free_text":[]},"mechanistic_narrative":"ALOX15B is a non-heme iron-containing lipoxygenase that oxygenates arachidonic acid and other polyunsaturated fatty acids at the C-15 position to generate 15S-HpETE/15S-HETE, with product specificity determined by active-site residues Asp602/Val603 [PMID:10393855, PMID:37373195]. The enzyme translocates to the plasma membrane upon Ca²⁺ stimulation via a membrane insertion loop and can oxygenate phospholipid-esterified substrates within bilayers; its membrane retention depends on S-palmitoylation, which is removed by ABHD17C downstream of KRAS/ERK1 signaling, targeting ALOX15B for CUL4/DDB1/DCAF10-mediated proteasomal degradation [PMID:27435673, PMID:40569151]. ALOX15B-derived lipid peroxides activate ERK1/2 to sustain SREBP2-dependent cholesterol biosynthesis in macrophages, promote PASMC proliferation via ERK/p38 MAPK, modulate keratinocyte inflammation through EGFR/JAK1/STAT1, and induce ferroptosis in cancer cells through p53/SLC7A11-dependent and IRF1-driven mechanisms [PMID:38581859, PMID:22018966, PMID:39843435, PMID:36801644, PMID:40749811]. In vivo, the balance between 15- and 8-hydroperoxide products determines divergent pro- and anti-inflammatory outcomes, as demonstrated by knock-in mice with humanized product specificity [PMID:37446212, PMID:35740398]."},"prefetch_data":{"uniprot":{"accession":"O15296","full_name":"Polyunsaturated fatty acid lipoxygenase ALOX15B","aliases":["15-lipoxygenase 2","15-LOX-2","Arachidonate 15-lipoxygenase B","15-LOX-B","Arachidonate 15-lipoxygenase type II","Linoleate 13-lipoxygenase 15-LOb"],"length_aa":676,"mass_kda":75.9,"function":"Non-heme iron-containing dioxygenase that catalyzes the stereo-specific peroxidation of free and esterified polyunsaturated fatty acids (PUFAs) generating a spectrum of bioactive lipid mediators (Probable) (PubMed:10542053, PubMed:10625675, PubMed:12704195, PubMed:17493578, PubMed:18311922, PubMed:24282679, PubMed:24497644, PubMed:32404334, PubMed:9177185). It inserts peroxyl groups at C15 of arachidonate ((5Z,8Z,11Z,14Z)-eicosatetraenoate) producing (15S)-hydroperoxyeicosatetraenoate/(15S)-HPETE (Probable) (PubMed:10625675, PubMed:11956198, PubMed:12704195, PubMed:17493578, PubMed:24282679, PubMed:24497644, PubMed:9177185). Also peroxidizes linoleate ((9Z,12Z)-octadecadienoate) to 13-hydroperoxyoctadecadienoate/13-HPODE (Probable) (PubMed:10542053, PubMed:27435673). Oxygenates arachidonyl derivatives such as 2-arachidonoylglycerol (2-AG) leading to the production and extracellular release of 15-hydroxyeicosatetraenoyl glycerol (15-HETE-G) that acts as a peroxisome proliferator-activated receptor alpha agonist (PubMed:11956198, PubMed:17493578, PubMed:18311922). Has the ability to efficiently class-switch ALOX5 pro-inflammatory mediators into anti-inflammatory intermediates (PubMed:27145229). Participates in the sequential oxidations of DHA ((4Z,7Z,10Z,13Z,16Z,19Z)-docosahexaenoate) to generate specialized pro-resolving mediators (SPMs) resolvin D5 ((7S,17S)-diHPDHA), which can actively down-regulate the immune response and have anti-aggregation properties with platelets (PubMed:32404334). In addition to free PUFAs hydrolyzed from phospholipids, it directly oxidizes PUFAs esterified to membrane-bound phospholipids (PubMed:27435673). Has no detectable 8S-lipoxygenase activity on arachidonate but reacts with (8S)-HPETE to produce (8S,15S)-diHPETE (Probable). May regulate progression through the cell cycle and cell proliferation (PubMed:11839751, PubMed:12704195). May also regulate cytokine secretion by macrophages and therefore play a role in the immune response (PubMed:18067895). May also regulate macrophage differentiation into proatherogenic foam cells (PubMed:22912809) Does not convert arachidonic acid to 15S-hydroperoxyeicosatetraenoic acid/(15S)-HPETE","subcellular_location":"Cytoplasm, cytosol; Cell membrane; Cytoplasm, cytoskeleton; Membrane; Cell junction, adherens junction; Cell junction, focal adhesion","url":"https://www.uniprot.org/uniprotkb/O15296/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/ALOX15B","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/ALOX15B","total_profiled":1310},"omim":[{"mim_id":"607206","title":"ARACHIDONATE LIPOXYGENASE 3; ALOXE3","url":"https://www.omim.org/entry/607206"},{"mim_id":"603741","title":"ARACHIDONATE 12-LIPOXYGENASE, R TYPE; ALOX12B","url":"https://www.omim.org/entry/603741"},{"mim_id":"603697","title":"ARACHIDONATE 15-LIPOXYGENASE, SECOND TYPE; ALOX15B","url":"https://www.omim.org/entry/603697"},{"mim_id":"242100","title":"ICHTHYOSIS, CONGENITAL, AUTOSOMAL RECESSIVE 2; ARCI2","url":"https://www.omim.org/entry/242100"},{"mim_id":"152392","title":"ARACHIDONATE 15-LIPOXYGENASE; ALOX15","url":"https://www.omim.org/entry/152392"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Plasma membrane","reliability":"Supported"},{"location":"Cytosol","reliability":"Supported"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"breast","ntpm":105.2},{"tissue":"prostate","ntpm":68.6}],"url":"https://www.proteinatlas.org/search/ALOX15B"},"hgnc":{"alias_symbol":["15-LOX-2"],"prev_symbol":[]},"alphafold":{"accession":"O15296","domains":[{"cath_id":"2.60.60.20","chopping":"2-23_86-119","consensus_level":"medium","plddt":93.2873,"start":2,"end":119}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O15296","model_url":"https://alphafold.ebi.ac.uk/files/AF-O15296-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O15296-F1-predicted_aligned_error_v6.png","plddt_mean":95.19},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=ALOX15B","jax_strain_url":"https://www.jax.org/strain/search?query=ALOX15B"},"sequence":{"accession":"O15296","fasta_url":"https://rest.uniprot.org/uniprotkb/O15296.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O15296/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O15296"}},"corpus_meta":[{"pmid":"10393855","id":"PMC_10393855","title":"15-lipoxygenase-2 (15-LOX-2) is expressed in benign prostatic epithelium and reduced in prostate adenocarcinoma.","date":"1999","source":"The American journal of pathology","url":"https://pubmed.ncbi.nlm.nih.gov/10393855","citation_count":134,"is_preprint":false},{"pmid":"16556493","id":"PMC_16556493","title":"Reduction of isoforms of 15-lipoxygenase (15-LOX)-1 and 15-LOX-2 in human breast cancer.","date":"2006","source":"Prostaglandins, leukotrienes, and essential fatty acids","url":"https://pubmed.ncbi.nlm.nih.gov/16556493","citation_count":83,"is_preprint":false},{"pmid":"36801644","id":"PMC_36801644","title":"p53 Activates the Lipoxygenase Activity of ALOX15B via Inhibiting SLC7A11 to Induce Ferroptosis in Bladder Cancer Cells.","date":"2023","source":"Laboratory investigation; a journal of technical methods and pathology","url":"https://pubmed.ncbi.nlm.nih.gov/36801644","citation_count":37,"is_preprint":false},{"pmid":"27435673","id":"PMC_27435673","title":"Membrane-dependent Activities of Human 15-LOX-2 and Its Murine Counterpart: IMPLICATIONS FOR MURINE MODELS OF ATHEROSCLEROSIS.","date":"2016","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/27435673","citation_count":36,"is_preprint":false},{"pmid":"18156936","id":"PMC_18156936","title":"Loss of heterozygosity of 17p13, with possible involvement of ACADVL and ALOX15B, in the pathogenesis of adrenocortical tumors.","date":"2008","source":"Annals of surgery","url":"https://pubmed.ncbi.nlm.nih.gov/18156936","citation_count":33,"is_preprint":false},{"pmid":"25895668","id":"PMC_25895668","title":"Modulation of Pulmonary Vascular Remodeling in Hypoxia: Role of 15-LOX-2/15-HETE-MAPKs Pathway.","date":"2015","source":"Cellular physiology and biochemistry : international journal of experimental cellular physiology, biochemistry, and pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/25895668","citation_count":33,"is_preprint":false},{"pmid":"38581859","id":"PMC_38581859","title":"ALOX15B controls macrophage cholesterol homeostasis via lipid peroxidation, ERK1/2 and SREBP2.","date":"2024","source":"Redox biology","url":"https://pubmed.ncbi.nlm.nih.gov/38581859","citation_count":20,"is_preprint":false},{"pmid":"32153408","id":"PMC_32153408","title":"Brozopine Inhibits 15-LOX-2 Metabolism Pathway After Transient Focal Cerebral Ischemia in Rats and OGD/R-Induced Hypoxia Injury in PC12 Cells.","date":"2020","source":"Frontiers in pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/32153408","citation_count":17,"is_preprint":false},{"pmid":"35344833","id":"PMC_35344833","title":"The role of ALOX15B in heat stress-induced apoptosis of porcine sertoli cells.","date":"2022","source":"Theriogenology","url":"https://pubmed.ncbi.nlm.nih.gov/35344833","citation_count":14,"is_preprint":false},{"pmid":"35740398","id":"PMC_35740398","title":"Male Knock-in Mice Expressing an Arachidonic Acid Lipoxygenase 15B (Alox15B) with Humanized Reaction Specificity Are Prematurely Growth Arrested When Aging.","date":"2022","source":"Biomedicines","url":"https://pubmed.ncbi.nlm.nih.gov/35740398","citation_count":14,"is_preprint":false},{"pmid":"24373925","id":"PMC_24373925","title":"Association of polymorphisms in the ALOX15B gene with coronary artery disease.","date":"2013","source":"Clinical biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/24373925","citation_count":12,"is_preprint":false},{"pmid":"22018966","id":"PMC_22018966","title":"Hypoxia promotes rabbit pulmonary artery smooth muscle cells proliferation through a 15-LOX-2 product 15(S)-hydroxyeicosatetraenoic acid.","date":"2011","source":"Prostaglandins, leukotrienes, and essential fatty acids","url":"https://pubmed.ncbi.nlm.nih.gov/22018966","citation_count":12,"is_preprint":false},{"pmid":"37446212","id":"PMC_37446212","title":"Humanization of the Reaction Specificity of Mouse Alox15b Inversely Modified the Susceptibility of Corresponding Knock-In Mice in Two Different Animal Inflammation Models.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37446212","citation_count":7,"is_preprint":false},{"pmid":"40569151","id":"PMC_40569151","title":"KRAS/ABHD17C/ALOX15B Axis Promotes Pancreatic Cancer Progression via Ferroptosis Evasion.","date":"2025","source":"Advanced science (Weinheim, Baden-Wurttemberg, Germany)","url":"https://pubmed.ncbi.nlm.nih.gov/40569151","citation_count":6,"is_preprint":false},{"pmid":"39843435","id":"PMC_39843435","title":"RNAi-based ALOX15B silencing augments keratinocyte inflammation in vitro via EGFR/STAT1/JAK1 signalling.","date":"2025","source":"Cell death & disease","url":"https://pubmed.ncbi.nlm.nih.gov/39843435","citation_count":6,"is_preprint":false},{"pmid":"22829730","id":"PMC_22829730","title":"Qualitative and Quantitative analysis of 3D predicted arachidonate 15-lipoxygenase-B (15-LOX-2) from Homo sapiens.","date":"2012","source":"Bioinformation","url":"https://pubmed.ncbi.nlm.nih.gov/22829730","citation_count":4,"is_preprint":false},{"pmid":"37373195","id":"PMC_37373195","title":"Functional Characterization of Mouse and Human Arachidonic Acid Lipoxygenase 15B (ALOX15B) Orthologs and of Their Mutants Exhibiting Humanized and Murinized Reaction Specificities.","date":"2023","source":"International journal of molecular sciences","url":"https://pubmed.ncbi.nlm.nih.gov/37373195","citation_count":3,"is_preprint":false},{"pmid":"41207352","id":"PMC_41207352","title":"ALOX15 and ALOX15B regulate autophagy to promote pulmonary arterial hypertension via the PI3K/AKT/mTOR pathway.","date":"2025","source":"European journal of pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41207352","citation_count":1,"is_preprint":false},{"pmid":"41527135","id":"PMC_41527135","title":"Low expression of ALOX15B modulates immunosuppressive tumor microenvironment in diffuse large B-cell lymphoma via the TAP1/MHC-I axis.","date":"2026","source":"Journal of experimental & clinical cancer research : CR","url":"https://pubmed.ncbi.nlm.nih.gov/41527135","citation_count":0,"is_preprint":false},{"pmid":"40749811","id":"PMC_40749811","title":"IRF1 transcriptionally activates ALOX15B to enhance ferroptosis sensitivity in triple-negative breast cancer.","date":"2025","source":"Biochimica et biophysica acta. General subjects","url":"https://pubmed.ncbi.nlm.nih.gov/40749811","citation_count":0,"is_preprint":false},{"pmid":"40044044","id":"PMC_40044044","title":"The reaction specificity of mammalian ALOX15B orthologs does not depend on the evolutionary ranking of the animals.","date":"2025","source":"Journal of lipid research","url":"https://pubmed.ncbi.nlm.nih.gov/40044044","citation_count":0,"is_preprint":false},{"pmid":"41843143","id":"PMC_41843143","title":"Targeting CEBPA/ALOX15B attenuates postmenopausal osteoporosis by inhibiting ferroptosis through the AMPK/mTOR signaling pathway.","date":"2026","source":"Inflammation research : official journal of the European Histamine Research Society ... [et al.]","url":"https://pubmed.ncbi.nlm.nih.gov/41843143","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":15032,"output_tokens":4686,"usd":0.057693},"stage2":{"model":"claude-opus-4-6","input_tokens":8139,"output_tokens":2734,"usd":0.163568},"total_usd":0.221261,"stage1_batch_id":"msgbatch_01TqNM6p6FsoMBT2jzQTwKBr","stage2_batch_id":"msgbatch_01Ya473eco8sTHbvRymQaU8o","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1999,\n      \"finding\": \"Human 15-LOX-2 (ALOX15B) catalyzes the oxygenation of arachidonic acid to 15S-HETE as its major product; this activity was demonstrated in benign prostate tissue incubated with [14C]arachidonic acid, with 15-HETE confirmed as the dominant metabolite by HPLC.\",\n      \"method\": \"Radiolabeled substrate incubation with tissue, reverse- and straight-phase HPLC product identification; immunohistochemistry for localization\",\n      \"journal\": \"The American journal of pathology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — direct enzymatic product identification in tissue, replicated in multiple specimens, foundational paper with >100 citations\",\n      \"pmids\": [\"10393855\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"Human ALOX15B generates a 15-S-hydroperoxy product from arachidonic acid while murine Alox15b generates an 8-S-product; both enzymes can oxygenate phospholipid-esterified arachidonic acid in a bilayer context (nanodiscs) to a 15-S-product. ALOX15B translocates to the plasma membrane upon Ca2+ ionophore stimulation, and this membrane localization is dependent on a putative membrane insertion loop.\",\n      \"method\": \"In vitro enzyme assays with nanodiscs as membrane mimics; transfected HEK293 cell imaging; site-directed mutagenesis of membrane insertion loop\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — reconstitution with membrane mimics, mutagenesis, and live-cell localization with functional consequence in single rigorous study\",\n      \"pmids\": [\"27435673\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"The distinct reaction specificities of human ALOX15B (15-hydroperoxy product) versus mouse Alox15b (8-hydroperoxy product) are determined by residues at positions 602-603 (Asp602/Val603 in human; Tyr603/His604 in mouse). Asp602Tyr+Val603His exchange in human ALOX15B murinized its product pattern, while Tyr603Asp+His604Val substitution in mouse Alox15b humanized it; in silico substrate docking supports an inverse substrate binding mechanism.\",\n      \"method\": \"Recombinant protein expression, in vitro enzyme activity assays with multiple polyunsaturated fatty acid substrates, active-site mutagenesis, molecular dynamics simulation and substrate docking\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — in vitro reconstitution with mutagenesis, multiple substrates, and computational validation confirming mechanism\",\n      \"pmids\": [\"37373195\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"15-LOX-2 product 15(S)-HETE promotes proliferation of pulmonary artery smooth muscle cells (PASMCs) under hypoxia via ERK1/2 (MEK/ERK) phosphorylation; this proliferative effect is blocked by MEK inhibitors PD-98059 and U0126, and by 15-LOX inhibitors NDGA and CDC.\",\n      \"method\": \"Cultured rabbit PASMC proliferation assays, BrdU incorporation, Western blotting for ERK1/2 phosphorylation, pharmacological inhibitors\",\n      \"journal\": \"Prostaglandins, leukotrienes, and essential fatty acids\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — defined cellular pathway via pharmacological epistasis with multiple inhibitors, single lab\",\n      \"pmids\": [\"22018966\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"15-LOX-2/15-HETE signaling promotes pulmonary arterial smooth muscle cell (PASMC) proliferation, cell cycle progression, migration, and suppression of apoptosis under hypoxia through activation of ERK and p38 MAPK phosphorylation.\",\n      \"method\": \"TUNEL assay, flow cytometry, BrdU incorporation, Western blotting for p-ERK and p-p38MAPK in cultured PASMCs and PAH patient/rat lungs\",\n      \"journal\": \"Cellular physiology and biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple cellular readouts in vitro and human/animal tissue; pathway placement via downstream kinase analysis\",\n      \"pmids\": [\"25895668\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"p53 activates ALOX15B lipoxygenase activity by suppressing SLC7A11 (cystine transporter), thereby inducing ferroptosis in bladder cancer cells; knockdown of ALOX15B protects bladder cancer cells from p53-induced ferroptosis.\",\n      \"method\": \"shRNA/oe-plasmid transfection, p53 agonist Nutlin-3a treatment, ferroptosis inhibitor ferrostatin-1, iron chelator deferoxamine, in vitro and in vivo tumor models\",\n      \"journal\": \"Laboratory investigation\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic epistasis (p53→SLC7A11→ALOX15B) with multiple pharmacological controls and in vivo validation\",\n      \"pmids\": [\"36801644\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"ALOX15B controls macrophage cholesterol homeostasis through a lipid peroxidation→ERK1/2→SREBP2 axis: ALOX15B-mediated lipid peroxidation activates ERK1/2, which sustains nuclear SREBP2 abundance and activity, thereby regulating cholesterol biosynthetic gene expression and sterol intermediates (desmosterol, lathosterol, 25- and 27-hydroxycholesterol).\",\n      \"method\": \"siRNA silencing of ALOX15B in primary human macrophages, global transcriptome analysis, immunofluorescence, ERK1/2 inhibition, NPC1 inhibition, sterol quantification by mass spectrometry\",\n      \"journal\": \"Redox biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (transcriptomics, immunofluorescence, pharmacological epistasis, metabolite quantification) in primary human cells establishing pathway mechanism\",\n      \"pmids\": [\"38581859\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ALOX15B silencing in human epidermal keratinocytes augments inflammation by reducing EGFR expression, leading to enhanced JAK1/STAT1 signaling and increased CCL2, CCL5, and CXCL10 secretion; reduced ERK phosphorylation downstream of EGFR also decreases cholesterol biosynthesis gene expression and depletes plasma membrane cholesterol/lipid rafts.\",\n      \"method\": \"siRNA knockdown, lipoxygenase inhibitor ML351, JAK1/STAT1 pathway inhibition, EGFR inhibition, confocal microscopy for membrane lipids, cytokine quantification, skin equivalents\",\n      \"journal\": \"Cell death & disease\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal approaches (siRNA, pharmacological inhibition, live imaging) linking ALOX15B to EGFR/JAK1/STAT1 pathway in human keratinocytes\",\n      \"pmids\": [\"39843435\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In pancreatic cancer, KRAS-mutant/ERK1-driven phosphorylation of ABHD17C promotes depalmitoylation of ALOX15B and its translocation from the plasma membrane to the cytoplasm, leading to proteasome-dependent degradation via the CUL4/DDB1/DCAF10 E3 ligase complex; restoration of S-palmitoylation by methyl protodioscin (which disrupts ABHD17C/ALOX15B interaction) re-localizes ALOX15B to the membrane and induces ferroptosis.\",\n      \"method\": \"Co-IP (ABHD17C–ALOX15B interaction), palmitoylation assays, proteasome inhibition, subcellular fractionation, patient-derived organoids, in vivo tumor models\",\n      \"journal\": \"Advanced science\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — identifies PTM (S-palmitoylation/depalmitoylation), E3 ligase complex, binding partner, and subcellular localization with functional consequence in vitro and in vivo\",\n      \"pmids\": [\"40569151\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"In porcine Sertoli cells under heat stress, ALOX15B expression is upregulated and increases 8-HETE and 15-HETE levels, activating the p38-p53 pathway to promote apoptosis; p38 inhibition reduces ALOX15B expression, and p38/p53 feedback regulates ALOX15B and lipid peroxide levels.\",\n      \"method\": \"Metabolomics (LC-MS), siRNA knockdown, ALOX15B inhibitor baicalein, p38 inhibitor, p53 inhibitor, apoptosis assays\",\n      \"journal\": \"Theriogenology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple pharmacological and genetic approaches establishing a feedback loop between ALOX15B activity and p38-p53 pathway in defined cellular model\",\n      \"pmids\": [\"35344833\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Humanization of mouse Alox15b reaction specificity (Tyr603Asp+His604Val knock-in) in vivo alters the plasma oxylipidome and leads to a gender-specific (male-only) premature growth arrest and impaired red blood cell parameters in aging mice, indicating that ALOX15B product specificity (15- vs 8-HETE) has distinct physiological consequences in the hematopoietic system.\",\n      \"method\": \"Knock-in mouse model, plasma oxylipidomics, hematological parameter measurement, body weight tracking\",\n      \"journal\": \"Biomedicines\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo genetic model with defined molecular change and quantitative physiological phenotype, single lab\",\n      \"pmids\": [\"35740398\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Humanization of mouse Alox15b reaction specificity (knock-in Tyr603Asp+His604Val) sensitizes female mice to dextran sodium sulfate-induced colitis (more weight loss, slower recovery) but partially protects in complete Freund's adjuvant-induced paw edema, demonstrating that the 15-hydroperoxy versus 8-hydroperoxy product balance of ALOX15B determines divergent pro- and anti-inflammatory outcomes in distinct disease contexts.\",\n      \"method\": \"Knock-in mouse models, DSS colitis model, CFA paw edema model, eicosanoid profiling, pain perception tests\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo genetic epistasis with two inflammation models and metabolite profiling, single lab\",\n      \"pmids\": [\"37446212\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Non-synonymous polymorphic variants of ALOX15B (p.Arg486His, p.Gln656Arg, p.Ile676Val) show similar enzyme activity and Michaelis-Menten kinetics to wild-type ALOX15B when expressed and assayed in vitro, indicating these common variants do not alter catalytic function.\",\n      \"method\": \"Recombinant protein expression, in vitro enzyme activity assays, Michaelis-Menten kinetics\",\n      \"journal\": \"Clinical biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 — direct in vitro enzyme kinetics for multiple variants, but single lab and limited mechanistic follow-up\",\n      \"pmids\": [\"24373925\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"IRF1 directly transcriptionally activates ALOX15B by binding its promoter, as shown by dual-luciferase reporter assays, EMSA, and ChIP-qPCR; IRF1-driven ALOX15B expression promotes ferroptosis in TNBC cells by inhibiting SLC7A11 and GPX4, reducing glutathione, and increasing lipid oxidation.\",\n      \"method\": \"Dual-luciferase reporter assays, EMSA, ChIP-qPCR, siRNA knockdown, ALOX15B overexpression, ferroptosis marker quantification\",\n      \"journal\": \"Biochimica et biophysica acta. General subjects\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — multiple orthogonal methods (luciferase, EMSA, ChIP) confirming transcriptional regulation; functional consequence via ferroptosis assays\",\n      \"pmids\": [\"40749811\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"ALOX15B deficiency in DLBCL cells leads to upregulation of COX-2/PGE2 signaling and downregulation of the TAP1/MHC-I antigen presentation axis, promoting immune evasion; HDAC1/2 occupy the ALOX15B promoter to repress its expression, and HDAC inhibitor tucidinostat restores ALOX15B expression and antigen presentation.\",\n      \"method\": \"siRNA knockdown, luciferase reporter assay, ChIP-seq, ATAC-seq, murine and PDX models, immunohistochemistry\",\n      \"journal\": \"Journal of experimental & clinical cancer research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP-seq/ATAC-seq establish epigenetic mechanism; functional consequences validated in vivo, but single lab\",\n      \"pmids\": [\"41527135\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"ALOX15B expression in pulmonary artery endothelial cells is elevated in PAH and promotes endothelial cell proliferation and vascular remodeling; ALOX15B knockdown reduces hypoxia-induced autophagy in mouse PAECs, an effect reversed by PI3K inhibitor, placing ALOX15B upstream of the PI3K/AKT/mTOR pathway in autophagy regulation.\",\n      \"method\": \"siRNA knockdown, PI3K inhibitor treatment, Western blot, right heart catheterization, echocardiography, mouse PAH models (hypoxia ± Sugen5416), systemic knockout mice\",\n      \"journal\": \"European journal of pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — genetic (KO mice) and siRNA approaches with pharmacological epistasis in vitro and in vivo, single lab\",\n      \"pmids\": [\"41207352\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"CEBPA directly binds the ALOX15B promoter to transcriptionally activate it; the CEBPA/ALOX15B axis promotes ferroptosis in osteoblasts and contributes to bone loss in postmenopausal osteoporosis via the AMPK/mTOR pathway, as shown by ALOX15B knockout mice subjected to ovariectomy displaying attenuated bone loss and reduced ferroptosis markers.\",\n      \"method\": \"ChIP (CEBPA at ALOX15B promoter), siRNA/overexpression in hFOB 1.19 cells, AMPK/mTOR pathway inhibitors, ALOX15B knockout mouse OVX model, micro-CT, bone density analysis, ferroptosis marker assays\",\n      \"journal\": \"Inflammation research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — ChIP confirming direct transcriptional regulation, KO mouse model with in vivo phenotype, pharmacological pathway validation\",\n      \"pmids\": [\"41843143\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"ALOX15B is a non-heme iron dioxygenase that oxygenates arachidonic acid and other polyunsaturated fatty acids at the C-15 position (producing 15S-HpETE/15S-HETE) via a catalytic mechanism determined by active-site residues Asp602/Val603; it translocates to the plasma membrane upon Ca2+ stimulation in a membrane-insertion-loop-dependent manner and can oxygenate phospholipid-esterified substrates in bilayers. Its membrane localization is regulated by S-palmitoylation (removed by ABHD17C downstream of KRAS/ERK1), targeting ALOX15B for CUL4/DDB1/DCAF10-mediated proteasomal degradation. Its transcription is activated by IRF1 and CEBPA, and repressed epigenetically by HDAC1/2. Through lipid peroxidation, ALOX15B activates ERK1/2 to sustain SREBP2-driven cholesterol biosynthesis in macrophages, promotes PASMC proliferation via ERK/p38 MAPK, modulates keratinocyte inflammation through EGFR/JAK1/STAT1, and induces ferroptosis in cancer cells via a p53/SLC7A11-dependent mechanism, with its 15- versus 8-hydroperoxide product balance determining distinct pro- and anti-inflammatory outcomes in vivo.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"ALOX15B is a non-heme iron-containing lipoxygenase that oxygenates arachidonic acid and other polyunsaturated fatty acids at the C-15 position to generate 15S-HpETE/15S-HETE, with product specificity determined by active-site residues Asp602/Val603 [PMID:10393855, PMID:37373195]. The enzyme translocates to the plasma membrane upon Ca²⁺ stimulation via a membrane insertion loop and can oxygenate phospholipid-esterified substrates within bilayers; its membrane retention depends on S-palmitoylation, which is removed by ABHD17C downstream of KRAS/ERK1 signaling, targeting ALOX15B for CUL4/DDB1/DCAF10-mediated proteasomal degradation [PMID:27435673, PMID:40569151]. ALOX15B-derived lipid peroxides activate ERK1/2 to sustain SREBP2-dependent cholesterol biosynthesis in macrophages, promote PASMC proliferation via ERK/p38 MAPK, modulate keratinocyte inflammation through EGFR/JAK1/STAT1, and induce ferroptosis in cancer cells through p53/SLC7A11-dependent and IRF1-driven mechanisms [PMID:38581859, PMID:22018966, PMID:39843435, PMID:36801644, PMID:40749811]. In vivo, the balance between 15- and 8-hydroperoxide products determines divergent pro- and anti-inflammatory outcomes, as demonstrated by knock-in mice with humanized product specificity [PMID:37446212, PMID:35740398].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Establishing that ALOX15B is a 15S-HETE-producing lipoxygenase resolved the identity and dominant product of this second human 15-lipoxygenase isoform.\",\n      \"evidence\": \"Radiolabeled arachidonic acid incubation with benign prostate tissue, HPLC product identification\",\n      \"pmids\": [\"10393855\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Catalytic mechanism and active-site determinants of positional specificity unknown\", \"Subcellular localization dynamics not addressed\", \"No structural information available\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Linking the ALOX15B product 15(S)-HETE to PASMC proliferation via MEK/ERK1/2 placed the enzyme's lipid products within a defined mitogenic signaling cascade relevant to pulmonary vascular remodeling.\",\n      \"evidence\": \"BrdU incorporation, Western blot for p-ERK1/2, MEK inhibitors PD-98059 and U0126 in cultured rabbit PASMCs under hypoxia\",\n      \"pmids\": [\"22018966\", \"25895668\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct target of 15-HETE upstream of ERK not identified\", \"Pathway epistasis relies on pharmacological inhibitors without genetic confirmation in first study\", \"Human PASMC data limited\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"Demonstrating Ca²⁺-dependent plasma membrane translocation, membrane insertion loop dependency, and oxygenation of phospholipid-esterified substrates in nanodiscs established ALOX15B as a membrane-acting enzyme, not merely a cytosolic lipid oxygenase.\",\n      \"evidence\": \"Nanodisc reconstitution, site-directed mutagenesis of membrane insertion loop, live-cell imaging in transfected HEK293 cells\",\n      \"pmids\": [\"27435673\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of membrane insertion loop–bilayer interaction unresolved\", \"Lipid preferences at the membrane not systematically characterized\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Knock-in mice with humanized Alox15b product specificity revealed that the 15- versus 8-HETE product ratio has distinct in vivo physiological consequences including sex-specific hematopoietic and inflammatory phenotypes.\",\n      \"evidence\": \"Alox15b Tyr603Asp+His604Val knock-in mice, plasma oxylipidomics, hematological analysis, DSS colitis and CFA paw edema models\",\n      \"pmids\": [\"35740398\", \"37446212\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanistic targets of 15-HETE vs 8-HETE driving divergent inflammatory outcomes not identified\", \"Basis of sex specificity unknown\", \"Single lab generated both studies\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Identifying Asp602/Val603 as the determinants of human ALOX15B 15-lipoxygenating specificity resolved the molecular basis for the species-specific product difference between human and mouse orthologs.\",\n      \"evidence\": \"Reciprocal active-site mutagenesis of recombinant human and mouse enzymes, in vitro assays with multiple PUFA substrates, molecular dynamics\",\n      \"pmids\": [\"37373195\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal structure of ALOX15B to confirm docking predictions\", \"Whether other active-site residues contribute to fine-tuning specificity untested\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Placing ALOX15B downstream of p53 and upstream of ferroptosis via the SLC7A11/glutathione axis established a tumor-suppressive lipid peroxidation pathway in bladder cancer.\",\n      \"evidence\": \"shRNA knockdown, p53 agonist Nutlin-3a, ferrostatin-1 rescue, in vitro and xenograft tumor models\",\n      \"pmids\": [\"36801644\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct lipid peroxidation substrates driving ferroptosis not identified\", \"Whether ALOX15B enzymatic activity or protein scaffold is required not dissected\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Demonstrating that ALOX15B-mediated lipid peroxidation activates ERK1/2 to sustain nuclear SREBP2 and cholesterol biosynthesis in macrophages connected the enzyme to sterol metabolism and foam cell biology.\",\n      \"evidence\": \"siRNA in primary human macrophages, transcriptomics, ERK1/2 inhibition, sterol quantification by mass spectrometry\",\n      \"pmids\": [\"38581859\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Identity of the specific lipid peroxide species activating ERK1/2 unknown\", \"In vivo atherosclerosis relevance not tested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Discovery that KRAS/ERK1-driven ABHD17C depalmitoylates ALOX15B, triggering CUL4/DDB1/DCAF10-mediated proteasomal degradation, revealed a complete post-translational regulatory circuit controlling ALOX15B stability and ferroptotic capacity in pancreatic cancer.\",\n      \"evidence\": \"Co-IP, palmitoylation assays, proteasome inhibition, subcellular fractionation, patient-derived organoids, in vivo tumor models\",\n      \"pmids\": [\"40569151\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Palmitoylation site(s) on ALOX15B not mapped\", \"Whether this degradation pathway operates in non-cancer cells unknown\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identifying IRF1 and CEBPA as direct transcriptional activators of ALOX15B and HDAC1/2 as epigenetic repressors defined the transcriptional control layer governing ALOX15B expression across cancer, immune evasion, and bone homeostasis contexts.\",\n      \"evidence\": \"ChIP-qPCR/ChIP-seq, EMSA, dual-luciferase reporters, HDAC inhibitor treatment, ALOX15B KO mice with OVX\",\n      \"pmids\": [\"40749811\", \"41527135\", \"41843143\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Relative contributions of IRF1, CEBPA, and HDAC1/2 in the same cell type not compared\", \"Whether additional transcription factors regulate tissue-specific expression unknown\", \"Chromatin architecture at the ALOX15B locus not fully characterized\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"Major unresolved questions include: the crystal structure of ALOX15B, the identity of specific lipid peroxide species that activate ERK1/2, the palmitoylation site(s), and how the enzyme's dual pro-inflammatory (15-HETE) and context-dependent anti-inflammatory roles are balanced in human disease.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No solved 3D structure\", \"Direct lipid peroxide mediator of ERK activation not identified\", \"S-palmitoylation site(s) not mapped\", \"In vivo human genetic evidence linking ALOX15B variants to disease absent\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0016491\", \"supporting_discovery_ids\": [0, 1, 2]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [1, 8]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 8]},\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [8]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [0, 1, 2, 6]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [3, 4, 6, 7]},\n      {\"term_id\": \"R-HSA-5357801\", \"supporting_discovery_ids\": [5, 8, 13, 16]},\n      {\"term_id\": \"R-HSA-392499\", \"supporting_discovery_ids\": [8]},\n      {\"term_id\": \"R-HSA-168256\", \"supporting_discovery_ids\": [14]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"ABHD17C\",\n      \"DCAF10\",\n      \"DDB1\",\n      \"CUL4A\",\n      \"IRF1\",\n      \"CEBPA\",\n      \"HDAC1\",\n      \"SLC7A11\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}