{"gene":"SLC25A17","run_date":"2026-04-28T20:42:07","timeline":{"discoveries":[{"year":1998,"finding":"Human PMP34 (SLC25A17) was identified as a peroxisomal integral membrane protein belonging to the mitochondrial solute carrier family, with six membrane-spanning domains. Its peroxisomal localization was established by fluorescence microscopy of HePG2 cells and mouse fibroblasts transfected with HsPMP34/GFP fusion protein, which colocalized with peroxisomal thiolase. In PEX5 knockout fibroblasts lacking functional peroxisomes, the fusion protein distributed to larger, less-abundant structures, confirming peroxisomal targeting.","method":"GFP fusion protein transfection, indirect immunofluorescence, co-localization with peroxisomal marker","journal":"European journal of biochemistry","confidence":"Medium","confidence_rationale":"Tier 2 — direct localization experiment with functional validation in PEX5-KO cells, single lab","pmids":["9874197"],"is_preprint":false},{"year":2000,"finding":"Transmembrane topology of PMP34 (SLC25A17) was determined: both N- and C-terminal parts face the cytosol, opposite to PMP47. The basic residue-containing loop between transmembrane segments 4 and 5 is required for peroxisome targeting (Ala substitution of basic residues abrogated activity), and three flanking hydrophobic transmembrane segments are essential for membrane integration into peroxisomes.","method":"Differential permeabilization, immunofluorescence of epitope-tagged variants, deletion mutagenesis, GFP fusion expression in CHO-K1 cells","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1-2 — topology determined by differential permeabilization and mutagenesis, multiple orthogonal methods in single rigorous study","pmids":["11121399"],"is_preprint":false},{"year":2002,"finding":"PMP34 (SLC25A17) was identified as a peroxisomal adenine nucleotide transporter. Purified PMP34 reconstituted in proteoliposomes directly transported adenine nucleotides. Functional rescue of defective medium-chain fatty acid oxidation in S. cerevisiae ANT1-disrupted cells (lacking the peroxisomal adenine nucleotide carrier) by human PMP34 provided genetic epistasis evidence.","method":"Protein reconstitution in proteoliposomes, transport assay, genetic complementation in yeast ANT1 mutant","journal":"Biochemical and biophysical research communications","confidence":"High","confidence_rationale":"Tier 1-2 — in vitro reconstitution plus genetic complementation, two orthogonal methods","pmids":["12445829"],"is_preprint":false},{"year":2012,"finding":"Recombinant SLC25A17 reconstituted into liposomes transports CoA, FAD, FMN, and AMP, and to a lesser extent NAD+, PAP, and ADP, functioning almost exclusively by counter-exchange mechanism. Kinetic parameters were determined; transport was saturable and inhibited by pyridoxal 5'-phosphate and other mitochondrial carrier inhibitors. The primary physiological role is import of free CoA, FAD, and NAD+ into peroxisomes in exchange for intraperoxisomally generated PAP, FMN, and AMP.","method":"Recombinant protein expression, reconstitution into liposomes, transport assays, kinetic characterization, inhibitor studies","journal":"The Biochemical journal","confidence":"High","confidence_rationale":"Tier 1 — rigorous in vitro reconstitution with kinetics and pharmacology, 127 citations indicating broad acceptance","pmids":["22185573"],"is_preprint":false},{"year":2019,"finding":"In zebrafish, slc25a17 knockdown compromised peroxisome function and altered lipid composition. Injection of CoA, but not NAD+, rescued the defective swim bladder phenotype caused by slc25a17 knockdown, establishing CoA transport as the primary in vivo function of Slc25a17.","method":"Morpholino knockdown in zebrafish, metabolite rescue experiments, lipid composition analysis","journal":"Journal of cellular physiology","confidence":"Medium","confidence_rationale":"Tier 2 — in vivo KD with substrate-specific rescue, single lab","pmids":["31187491"],"is_preprint":false},{"year":2020,"finding":"PMP34-deficient mice (Slc25a17 gene trap) showed impaired degradation of phytanic and pristanic acid upon dietary phytol administration, with hepatomegaly, liver inflammation, and accumulation of phytanic acid, pristanic acid, and their CoA esters. Other peroxisomal pathways (bile acid formation, plasmalogen synthesis, VLCFA metabolism) were unaffected, indicating that PMP34 specifically supports peroxisomal CoA availability for branched-chain fatty acid oxidation.","method":"Gene-trap knockout mice, dietary challenge, lipid metabolite analysis (acyl-CoA profiling, bile acid analysis), fibroblast fatty acid oxidation assays","journal":"Frontiers in cell and developmental biology","confidence":"High","confidence_rationale":"Tier 2 — clean KO with multiple metabolic readouts and dietary challenge, pathway specificity established","pmids":["32266253"],"is_preprint":false},{"year":2023,"finding":"Inactivation of SLC25A17 in HEK-293, HeLa, and MEF cells shifted the glutathione redox couple toward a more reductive state (GSSG/GSH ratio decreased) and affected peroxisomal NADPH metabolism, establishing SLC25A17 as a maintainer of peroxisomal redox homeostasis. This phenotype was rescued by expression of Candida boidinii Pmp47 (orthologue). The redox changes were not due to altered antioxidant enzyme expression, catalase activity, H2O2 permeability, or mitochondrial fitness.","method":"CRISPR KO, redox biosensors, rescue with yeast orthologue Pmp47, catalase activity assay, H2O2 permeability assay","journal":"Free radical biology & medicine","confidence":"High","confidence_rationale":"Tier 2 — multiple cell lines, genetic rescue with orthologue, multiple orthogonal redox assays","pmids":["38159891"],"is_preprint":false},{"year":2025,"finding":"PEX3 interacts with SLC25A17 protein to upregulate its stability, and USF2 drives PEX3 transcriptional activation by directly binding the PEX3 promoter. This USF2-PEX3-SLC25A17 axis promotes JAK2/STAT3 pathway activation and abnormal lipid metabolism in lung adenocarcinoma cells.","method":"Co-immunoprecipitation (PEX3-SLC25A17 interaction), chromatin binding assay (USF2-PEX3 promoter), rescue experiments, JAK2 inhibitor (AG490), xenograft model","journal":"Toxicology and applied pharmacology","confidence":"Medium","confidence_rationale":"Tier 3 — Co-IP and rescue experiments, single lab, cancer-specific context","pmids":["40885408"],"is_preprint":false},{"year":2026,"finding":"MARCH1 E3 ubiquitin ligase directly ubiquitinates SLC25A17, promoting its proteasomal degradation. Loss of SLC25A17 stability via MARCH1 attenuates M2 macrophage polarization and cisplatin resistance in lung adenocarcinoma.","method":"Co-immunoprecipitation, ubiquitination assay, rescue experiments with SLC25A17 overexpression, flow cytometry, Western blotting","journal":"Integrative biology : quantitative biosciences from nano to macro","confidence":"Medium","confidence_rationale":"Tier 2-3 — ubiquitination assay and co-IP confirm MARCH1 as E3 ligase for SLC25A17, rescue validates functional link, single lab","pmids":["41758657"],"is_preprint":false}],"current_model":"SLC25A17 (PMP34) is a peroxisomal integral membrane protein that functions as a counter-exchange transporter of adenine-containing cofactors—primarily importing CoA, FAD, and NAD+ into the peroxisomal matrix in exchange for intraperoxisomally generated PAP, FMN, and AMP—thereby sustaining peroxisomal redox homeostasis and enabling key peroxisomal metabolic processes including branched-chain fatty acid oxidation; its peroxisomal targeting is mediated by a basic loop between transmembrane segments 4 and 5 flanked by hydrophobic segments, and its protein stability is regulated by the E3 ubiquitin ligase MARCH1."},"narrative":{"teleology":[{"year":1998,"claim":"Establishing that PMP34 is a peroxisomal membrane protein in the mitochondrial carrier family resolved its subcellular localization and placed it as a candidate peroxisomal solute transporter.","evidence":"GFP-fusion transfection in HepG2 and fibroblasts with co-localization to peroxisomal thiolase; mislocalization in PEX5-KO fibroblasts","pmids":["9874197"],"confidence":"Medium","gaps":["Transport substrate unknown","Endogenous protein expression pattern not characterized","Single-lab study without independent confirmation"]},{"year":2000,"claim":"Determining PMP34's transmembrane topology (both termini cytosolic) and identifying the basic loop between TM4–TM5 as the peroxisomal targeting signal established how the protein is directed to peroxisomes.","evidence":"Differential permeabilization, epitope-tagged deletion/substitution mutants in CHO-K1 cells","pmids":["11121399"],"confidence":"High","gaps":["Targeting receptor not identified","Whether the same signal operates in all cell types untested"]},{"year":2002,"claim":"Reconstitution of purified PMP34 in proteoliposomes demonstrated direct adenine nucleotide transport, and complementation of yeast ANT1 mutants confirmed functional equivalence, establishing PMP34 as a peroxisomal adenine nucleotide transporter.","evidence":"Proteoliposome transport assays with purified protein; genetic complementation in S. cerevisiae ant1Δ","pmids":["12445829"],"confidence":"High","gaps":["Full substrate specificity and kinetic parameters not yet determined","In vivo substrates in mammalian cells unresolved"]},{"year":2012,"claim":"Comprehensive kinetic characterization revealed that SLC25A17 operates as a counter-exchange transporter importing CoA, FAD, and NAD+ while exporting PAP, FMN, and AMP, defining its physiological role in peroxisomal cofactor supply.","evidence":"Recombinant protein reconstituted into liposomes with saturation kinetics, inhibitor profiling (pyridoxal 5'-phosphate), and substrate competition assays","pmids":["22185573"],"confidence":"High","gaps":["Relative contribution of each substrate pair in vivo unknown","Structural basis for substrate selectivity not resolved"]},{"year":2019,"claim":"In vivo rescue of slc25a17-knockdown zebrafish by CoA but not NAD+ injection identified CoA import as the primary physiological function, narrowing the substrate hierarchy observed in vitro.","evidence":"Morpholino knockdown in zebrafish with metabolite-specific rescue of swim bladder phenotype","pmids":["31187491"],"confidence":"Medium","gaps":["Morpholino off-target effects not fully excluded","Whether FAD transport contributes to other tissue-specific phenotypes untested","Single-lab study"]},{"year":2020,"claim":"PMP34-deficient mice showed selective impairment of branched-chain fatty acid (phytanic/pristanic acid) oxidation while other peroxisomal pathways were intact, demonstrating pathway-specific dependence on SLC25A17-mediated CoA import.","evidence":"Gene-trap KO mice with dietary phytol challenge, acyl-CoA and bile acid profiling, fibroblast β-oxidation assays","pmids":["32266253"],"confidence":"High","gaps":["Whether compensatory transporters exist for other peroxisomal pathways not identified","Neurological phenotypes not assessed"]},{"year":2023,"claim":"Demonstrating that SLC25A17 loss shifts the peroxisomal glutathione redox state toward reduction — rescuable by yeast orthologue Pmp47 — established SLC25A17 as a maintainer of peroxisomal redox homeostasis beyond fatty acid oxidation.","evidence":"CRISPR KO in HEK-293, HeLa, and MEFs with genetically encoded redox biosensors; rescue with C. boidinii Pmp47","pmids":["38159891"],"confidence":"High","gaps":["Which transported cofactor (NAD+, FAD, or CoA) mediates the redox effect not dissected","In vivo redox consequences in animal models not assessed"]},{"year":2025,"claim":"Identification of PEX3 as a stabilizer of SLC25A17 protein and USF2 as a transcriptional driver of PEX3 revealed an upstream regulatory axis controlling SLC25A17 abundance, linked to JAK2/STAT3 signaling in lung adenocarcinoma.","evidence":"Co-immunoprecipitation (PEX3–SLC25A17), ChIP (USF2–PEX3 promoter), JAK2 inhibitor AG490, xenograft model in lung adenocarcinoma cells","pmids":["40885408"],"confidence":"Medium","gaps":["Mechanism by which PEX3 stabilizes SLC25A17 unknown","Whether this regulatory axis operates in non-cancer cells not tested","Single-lab study"]},{"year":2026,"claim":"MARCH1 was identified as the E3 ubiquitin ligase that ubiquitinates SLC25A17 and targets it for proteasomal degradation, establishing a post-translational mechanism controlling transporter turnover.","evidence":"Co-immunoprecipitation, in vivo ubiquitination assay, SLC25A17 overexpression rescue of MARCH1 effects in lung adenocarcinoma cells","pmids":["41758657"],"confidence":"Medium","gaps":["Ubiquitination site(s) on SLC25A17 not mapped","Whether MARCH1-mediated regulation occurs in non-cancer tissues unknown","Single-lab study"]},{"year":null,"claim":"No high-resolution structure of SLC25A17 exists, and the molecular basis for its substrate selectivity among CoA, FAD, NAD+, and their exchange partners remains unresolved; whether SLC25A17 deficiency underlies a human Mendelian peroxisomal disorder has not been established.","evidence":"","pmids":[],"confidence":"High","gaps":["No crystal or cryo-EM structure","No human disease-causing mutations reported","Tissue-specific functions beyond liver and lung adenocarcinoma unexplored"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[2,3,4]}],"localization":[{"term_id":"GO:0005777","term_label":"peroxisome","supporting_discovery_ids":[0,1]}],"pathway":[{"term_id":"R-HSA-1430728","term_label":"Metabolism","supporting_discovery_ids":[3,4,5]},{"term_id":"R-HSA-382551","term_label":"Transport of small molecules","supporting_discovery_ids":[2,3]}],"complexes":[],"partners":["PEX3","MARCH1"],"other_free_text":[]},"mechanistic_narrative":"SLC25A17 (PMP34) is a peroxisomal integral membrane transporter that sustains peroxisomal metabolism by importing CoA, FAD, and NAD+ into the peroxisomal matrix in counter-exchange for intraperoxisomally generated PAP, FMN, and AMP [PMID:22185573]. Peroxisomal targeting depends on basic residues within the loop between transmembrane segments 4 and 5 flanked by hydrophobic domains, and both termini face the cytosol [PMID:11121399]. Loss of SLC25A17 specifically impairs branched-chain fatty acid (phytanic/pristanic acid) oxidation through limiting peroxisomal CoA availability and shifts the peroxisomal glutathione redox couple toward a more reductive state [PMID:32266253, PMID:38159891]. SLC25A17 protein stability is regulated by interaction with PEX3 and by MARCH1-mediated ubiquitination and proteasomal degradation [PMID:40885408, PMID:41758657]."},"prefetch_data":{"uniprot":{"accession":"O43808","full_name":"Peroxisomal membrane protein PMP34","aliases":["34 kDa peroxisomal membrane protein","Solute carrier family 25 member 17"],"length_aa":307,"mass_kda":34.6,"function":"Peroxisomal transporter for multiple cofactors like coenzyme A (CoA), flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN) and nucleotide adenosine monophosphate (AMP), and to a lesser extent for nicotinamide adenine dinucleotide (NAD(+)), adenosine diphosphate (ADP) and adenosine 3',5'-diphosphate (PAP). May catalyze the transport of free CoA, FAD and NAD(+) from the cytosol into the peroxisomal matrix by a counter-exchange mechanism","subcellular_location":"Cytoplasm; Peroxisome membrane","url":"https://www.uniprot.org/uniprotkb/O43808/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/SLC25A17","classification":"Not Classified","n_dependent_lines":1,"n_total_lines":1208,"dependency_fraction":0.0008278145695364238},"opencell":{"profiled":true,"resolved_as":"","ensg_id":"ENSG00000100372","cell_line_id":"CID000893","localizations":[{"compartment":"vesicles","grade":3}],"interactors":[{"gene":"ARID4B","stoichiometry":10.0},{"gene":"PTGFRN","stoichiometry":0.2}],"url":"https://opencell.sf.czbiohub.org/target/CID000893","total_profiled":1310},"omim":[{"mim_id":"606795","title":"SOLUTE CARRIER FAMILY 25 (MITOCHONDRIAL CARRIER), MEMBER 17; SLC25A17","url":"https://www.omim.org/entry/606795"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Supported","locations":[{"location":"Peroxisomes","reliability":"Supported"}],"tissue_specificity":"Low tissue specificity","tissue_distribution":"Detected in all","driving_tissues":[],"url":"https://www.proteinatlas.org/search/SLC25A17"},"hgnc":{"alias_symbol":["PMP34"],"prev_symbol":[]},"alphafold":{"accession":"O43808","domains":[{"cath_id":"1.50.40.10","chopping":"8-300","consensus_level":"medium","plddt":87.5845,"start":8,"end":300}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/O43808","model_url":"https://alphafold.ebi.ac.uk/files/AF-O43808-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-O43808-F1-predicted_aligned_error_v6.png","plddt_mean":85.38},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=SLC25A17","jax_strain_url":"https://www.jax.org/strain/search?query=SLC25A17"},"sequence":{"accession":"O43808","fasta_url":"https://rest.uniprot.org/uniprotkb/O43808.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/O43808/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/O43808"}},"corpus_meta":[{"pmid":"22185573","id":"PMC_22185573","title":"The human gene SLC25A17 encodes a peroxisomal transporter of coenzyme A, FAD and NAD+.","date":"2012","source":"The Biochemical journal","url":"https://pubmed.ncbi.nlm.nih.gov/22185573","citation_count":127,"is_preprint":false},{"pmid":"12445829","id":"PMC_12445829","title":"Identification of human PMP34 as a peroxisomal ATP transporter.","date":"2002","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/12445829","citation_count":84,"is_preprint":false},{"pmid":"9874197","id":"PMC_9874197","title":"Identification and characterization of human PMP34, a protein closely related to the peroxisomal integral membrane protein PMP47 of Candida boidinii.","date":"1998","source":"European journal of biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/9874197","citation_count":54,"is_preprint":false},{"pmid":"11121399","id":"PMC_11121399","title":"Topogenesis of peroxisomal membrane protein requires a short, positively charged intervening-loop sequence and flanking hydrophobic segments. study using human membrane protein PMP34.","date":"2000","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/11121399","citation_count":51,"is_preprint":false},{"pmid":"31187491","id":"PMC_31187491","title":"Slc25a17 acts as a peroxisomal coenzyme A transporter and regulates multiorgan development in zebrafish.","date":"2019","source":"Journal of cellular physiology","url":"https://pubmed.ncbi.nlm.nih.gov/31187491","citation_count":21,"is_preprint":false},{"pmid":"32266253","id":"PMC_32266253","title":"Slc25a17 Gene Trapped Mice: PMP34 Plays a Role in the Peroxisomal Degradation of Phytanic and Pristanic Acid.","date":"2020","source":"Frontiers in cell and developmental biology","url":"https://pubmed.ncbi.nlm.nih.gov/32266253","citation_count":21,"is_preprint":false},{"pmid":"38402166","id":"PMC_38402166","title":"SLC25A17 inhibits autophagy to promote triple-negative breast cancer tumorigenesis by ROS-mediated JAK2/STAT3 signaling pathway.","date":"2024","source":"Cancer cell international","url":"https://pubmed.ncbi.nlm.nih.gov/38402166","citation_count":16,"is_preprint":false},{"pmid":"34939235","id":"PMC_34939235","title":"Role of solute carrier transporters SLC25A17 and SLC27A6 in acquired resistance to enzalutamide in castration-resistant prostate cancer.","date":"2021","source":"Molecular carcinogenesis","url":"https://pubmed.ncbi.nlm.nih.gov/34939235","citation_count":14,"is_preprint":false},{"pmid":"38159891","id":"PMC_38159891","title":"The solute carrier SLC25A17 sustains peroxisomal redox homeostasis in diverse mammalian cell lines.","date":"2023","source":"Free radical biology & medicine","url":"https://pubmed.ncbi.nlm.nih.gov/38159891","citation_count":4,"is_preprint":false},{"pmid":"40885408","id":"PMC_40885408","title":"USF2 regulates the JAK2/STAT3 pathway through PEX3-mediated SLC25A17 upregulation to affect lipid metabolism and promote the progression of lung adenocarcinoma.","date":"2025","source":"Toxicology and applied pharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/40885408","citation_count":2,"is_preprint":false},{"pmid":"41758657","id":"PMC_41758657","title":"MARCH1 attenuates lung adenocarcinoma by blocking macrophage M2 polarization and cisplatin resistance through reducing SLC25A17 stability.","date":"2026","source":"Integrative biology : quantitative biosciences from nano to macro","url":"https://pubmed.ncbi.nlm.nih.gov/41758657","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":7276,"output_tokens":2462,"usd":0.029379},"stage2":{"model":"claude-opus-4-6","input_tokens":5758,"output_tokens":2266,"usd":0.12816},"total_usd":0.157539,"stage1_batch_id":"msgbatch_011rkcQdVV1RaFq9XhcG6df6","stage2_batch_id":"msgbatch_01RzgrJafdF4EWHhj5mNi6dh","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 1998,\n      \"finding\": \"Human PMP34 (SLC25A17) was identified as a peroxisomal integral membrane protein belonging to the mitochondrial solute carrier family, with six membrane-spanning domains. Its peroxisomal localization was established by fluorescence microscopy of HePG2 cells and mouse fibroblasts transfected with HsPMP34/GFP fusion protein, which colocalized with peroxisomal thiolase. In PEX5 knockout fibroblasts lacking functional peroxisomes, the fusion protein distributed to larger, less-abundant structures, confirming peroxisomal targeting.\",\n      \"method\": \"GFP fusion protein transfection, indirect immunofluorescence, co-localization with peroxisomal marker\",\n      \"journal\": \"European journal of biochemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — direct localization experiment with functional validation in PEX5-KO cells, single lab\",\n      \"pmids\": [\"9874197\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Transmembrane topology of PMP34 (SLC25A17) was determined: both N- and C-terminal parts face the cytosol, opposite to PMP47. The basic residue-containing loop between transmembrane segments 4 and 5 is required for peroxisome targeting (Ala substitution of basic residues abrogated activity), and three flanking hydrophobic transmembrane segments are essential for membrane integration into peroxisomes.\",\n      \"method\": \"Differential permeabilization, immunofluorescence of epitope-tagged variants, deletion mutagenesis, GFP fusion expression in CHO-K1 cells\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — topology determined by differential permeabilization and mutagenesis, multiple orthogonal methods in single rigorous study\",\n      \"pmids\": [\"11121399\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2002,\n      \"finding\": \"PMP34 (SLC25A17) was identified as a peroxisomal adenine nucleotide transporter. Purified PMP34 reconstituted in proteoliposomes directly transported adenine nucleotides. Functional rescue of defective medium-chain fatty acid oxidation in S. cerevisiae ANT1-disrupted cells (lacking the peroxisomal adenine nucleotide carrier) by human PMP34 provided genetic epistasis evidence.\",\n      \"method\": \"Protein reconstitution in proteoliposomes, transport assay, genetic complementation in yeast ANT1 mutant\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 — in vitro reconstitution plus genetic complementation, two orthogonal methods\",\n      \"pmids\": [\"12445829\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Recombinant SLC25A17 reconstituted into liposomes transports CoA, FAD, FMN, and AMP, and to a lesser extent NAD+, PAP, and ADP, functioning almost exclusively by counter-exchange mechanism. Kinetic parameters were determined; transport was saturable and inhibited by pyridoxal 5'-phosphate and other mitochondrial carrier inhibitors. The primary physiological role is import of free CoA, FAD, and NAD+ into peroxisomes in exchange for intraperoxisomally generated PAP, FMN, and AMP.\",\n      \"method\": \"Recombinant protein expression, reconstitution into liposomes, transport assays, kinetic characterization, inhibitor studies\",\n      \"journal\": \"The Biochemical journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 — rigorous in vitro reconstitution with kinetics and pharmacology, 127 citations indicating broad acceptance\",\n      \"pmids\": [\"22185573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"In zebrafish, slc25a17 knockdown compromised peroxisome function and altered lipid composition. Injection of CoA, but not NAD+, rescued the defective swim bladder phenotype caused by slc25a17 knockdown, establishing CoA transport as the primary in vivo function of Slc25a17.\",\n      \"method\": \"Morpholino knockdown in zebrafish, metabolite rescue experiments, lipid composition analysis\",\n      \"journal\": \"Journal of cellular physiology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — in vivo KD with substrate-specific rescue, single lab\",\n      \"pmids\": [\"31187491\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"PMP34-deficient mice (Slc25a17 gene trap) showed impaired degradation of phytanic and pristanic acid upon dietary phytol administration, with hepatomegaly, liver inflammation, and accumulation of phytanic acid, pristanic acid, and their CoA esters. Other peroxisomal pathways (bile acid formation, plasmalogen synthesis, VLCFA metabolism) were unaffected, indicating that PMP34 specifically supports peroxisomal CoA availability for branched-chain fatty acid oxidation.\",\n      \"method\": \"Gene-trap knockout mice, dietary challenge, lipid metabolite analysis (acyl-CoA profiling, bile acid analysis), fibroblast fatty acid oxidation assays\",\n      \"journal\": \"Frontiers in cell and developmental biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean KO with multiple metabolic readouts and dietary challenge, pathway specificity established\",\n      \"pmids\": [\"32266253\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Inactivation of SLC25A17 in HEK-293, HeLa, and MEF cells shifted the glutathione redox couple toward a more reductive state (GSSG/GSH ratio decreased) and affected peroxisomal NADPH metabolism, establishing SLC25A17 as a maintainer of peroxisomal redox homeostasis. This phenotype was rescued by expression of Candida boidinii Pmp47 (orthologue). The redox changes were not due to altered antioxidant enzyme expression, catalase activity, H2O2 permeability, or mitochondrial fitness.\",\n      \"method\": \"CRISPR KO, redox biosensors, rescue with yeast orthologue Pmp47, catalase activity assay, H2O2 permeability assay\",\n      \"journal\": \"Free radical biology & medicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — multiple cell lines, genetic rescue with orthologue, multiple orthogonal redox assays\",\n      \"pmids\": [\"38159891\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"PEX3 interacts with SLC25A17 protein to upregulate its stability, and USF2 drives PEX3 transcriptional activation by directly binding the PEX3 promoter. This USF2-PEX3-SLC25A17 axis promotes JAK2/STAT3 pathway activation and abnormal lipid metabolism in lung adenocarcinoma cells.\",\n      \"method\": \"Co-immunoprecipitation (PEX3-SLC25A17 interaction), chromatin binding assay (USF2-PEX3 promoter), rescue experiments, JAK2 inhibitor (AG490), xenograft model\",\n      \"journal\": \"Toxicology and applied pharmacology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — Co-IP and rescue experiments, single lab, cancer-specific context\",\n      \"pmids\": [\"40885408\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"MARCH1 E3 ubiquitin ligase directly ubiquitinates SLC25A17, promoting its proteasomal degradation. Loss of SLC25A17 stability via MARCH1 attenuates M2 macrophage polarization and cisplatin resistance in lung adenocarcinoma.\",\n      \"method\": \"Co-immunoprecipitation, ubiquitination assay, rescue experiments with SLC25A17 overexpression, flow cytometry, Western blotting\",\n      \"journal\": \"Integrative biology : quantitative biosciences from nano to macro\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2-3 — ubiquitination assay and co-IP confirm MARCH1 as E3 ligase for SLC25A17, rescue validates functional link, single lab\",\n      \"pmids\": [\"41758657\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"SLC25A17 (PMP34) is a peroxisomal integral membrane protein that functions as a counter-exchange transporter of adenine-containing cofactors—primarily importing CoA, FAD, and NAD+ into the peroxisomal matrix in exchange for intraperoxisomally generated PAP, FMN, and AMP—thereby sustaining peroxisomal redox homeostasis and enabling key peroxisomal metabolic processes including branched-chain fatty acid oxidation; its peroxisomal targeting is mediated by a basic loop between transmembrane segments 4 and 5 flanked by hydrophobic segments, and its protein stability is regulated by the E3 ubiquitin ligase MARCH1.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"SLC25A17 (PMP34) is a peroxisomal integral membrane transporter that sustains peroxisomal metabolism by importing CoA, FAD, and NAD+ into the peroxisomal matrix in counter-exchange for intraperoxisomally generated PAP, FMN, and AMP [PMID:22185573]. Peroxisomal targeting depends on basic residues within the loop between transmembrane segments 4 and 5 flanked by hydrophobic domains, and both termini face the cytosol [PMID:11121399]. Loss of SLC25A17 specifically impairs branched-chain fatty acid (phytanic/pristanic acid) oxidation through limiting peroxisomal CoA availability and shifts the peroxisomal glutathione redox couple toward a more reductive state [PMID:32266253, PMID:38159891]. SLC25A17 protein stability is regulated by interaction with PEX3 and by MARCH1-mediated ubiquitination and proteasomal degradation [PMID:40885408, PMID:41758657].\",\n  \"teleology\": [\n    {\n      \"year\": 1998,\n      \"claim\": \"Establishing that PMP34 is a peroxisomal membrane protein in the mitochondrial carrier family resolved its subcellular localization and placed it as a candidate peroxisomal solute transporter.\",\n      \"evidence\": \"GFP-fusion transfection in HepG2 and fibroblasts with co-localization to peroxisomal thiolase; mislocalization in PEX5-KO fibroblasts\",\n      \"pmids\": [\"9874197\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Transport substrate unknown\", \"Endogenous protein expression pattern not characterized\", \"Single-lab study without independent confirmation\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Determining PMP34's transmembrane topology (both termini cytosolic) and identifying the basic loop between TM4–TM5 as the peroxisomal targeting signal established how the protein is directed to peroxisomes.\",\n      \"evidence\": \"Differential permeabilization, epitope-tagged deletion/substitution mutants in CHO-K1 cells\",\n      \"pmids\": [\"11121399\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Targeting receptor not identified\", \"Whether the same signal operates in all cell types untested\"]\n    },\n    {\n      \"year\": 2002,\n      \"claim\": \"Reconstitution of purified PMP34 in proteoliposomes demonstrated direct adenine nucleotide transport, and complementation of yeast ANT1 mutants confirmed functional equivalence, establishing PMP34 as a peroxisomal adenine nucleotide transporter.\",\n      \"evidence\": \"Proteoliposome transport assays with purified protein; genetic complementation in S. cerevisiae ant1Δ\",\n      \"pmids\": [\"12445829\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Full substrate specificity and kinetic parameters not yet determined\", \"In vivo substrates in mammalian cells unresolved\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Comprehensive kinetic characterization revealed that SLC25A17 operates as a counter-exchange transporter importing CoA, FAD, and NAD+ while exporting PAP, FMN, and AMP, defining its physiological role in peroxisomal cofactor supply.\",\n      \"evidence\": \"Recombinant protein reconstituted into liposomes with saturation kinetics, inhibitor profiling (pyridoxal 5'-phosphate), and substrate competition assays\",\n      \"pmids\": [\"22185573\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Relative contribution of each substrate pair in vivo unknown\", \"Structural basis for substrate selectivity not resolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"In vivo rescue of slc25a17-knockdown zebrafish by CoA but not NAD+ injection identified CoA import as the primary physiological function, narrowing the substrate hierarchy observed in vitro.\",\n      \"evidence\": \"Morpholino knockdown in zebrafish with metabolite-specific rescue of swim bladder phenotype\",\n      \"pmids\": [\"31187491\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Morpholino off-target effects not fully excluded\", \"Whether FAD transport contributes to other tissue-specific phenotypes untested\", \"Single-lab study\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"PMP34-deficient mice showed selective impairment of branched-chain fatty acid (phytanic/pristanic acid) oxidation while other peroxisomal pathways were intact, demonstrating pathway-specific dependence on SLC25A17-mediated CoA import.\",\n      \"evidence\": \"Gene-trap KO mice with dietary phytol challenge, acyl-CoA and bile acid profiling, fibroblast β-oxidation assays\",\n      \"pmids\": [\"32266253\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Whether compensatory transporters exist for other peroxisomal pathways not identified\", \"Neurological phenotypes not assessed\"]\n    },\n    {\n      \"year\": 2023,\n      \"claim\": \"Demonstrating that SLC25A17 loss shifts the peroxisomal glutathione redox state toward reduction — rescuable by yeast orthologue Pmp47 — established SLC25A17 as a maintainer of peroxisomal redox homeostasis beyond fatty acid oxidation.\",\n      \"evidence\": \"CRISPR KO in HEK-293, HeLa, and MEFs with genetically encoded redox biosensors; rescue with C. boidinii Pmp47\",\n      \"pmids\": [\"38159891\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Which transported cofactor (NAD+, FAD, or CoA) mediates the redox effect not dissected\", \"In vivo redox consequences in animal models not assessed\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Identification of PEX3 as a stabilizer of SLC25A17 protein and USF2 as a transcriptional driver of PEX3 revealed an upstream regulatory axis controlling SLC25A17 abundance, linked to JAK2/STAT3 signaling in lung adenocarcinoma.\",\n      \"evidence\": \"Co-immunoprecipitation (PEX3–SLC25A17), ChIP (USF2–PEX3 promoter), JAK2 inhibitor AG490, xenograft model in lung adenocarcinoma cells\",\n      \"pmids\": [\"40885408\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism by which PEX3 stabilizes SLC25A17 unknown\", \"Whether this regulatory axis operates in non-cancer cells not tested\", \"Single-lab study\"]\n    },\n    {\n      \"year\": 2026,\n      \"claim\": \"MARCH1 was identified as the E3 ubiquitin ligase that ubiquitinates SLC25A17 and targets it for proteasomal degradation, establishing a post-translational mechanism controlling transporter turnover.\",\n      \"evidence\": \"Co-immunoprecipitation, in vivo ubiquitination assay, SLC25A17 overexpression rescue of MARCH1 effects in lung adenocarcinoma cells\",\n      \"pmids\": [\"41758657\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ubiquitination site(s) on SLC25A17 not mapped\", \"Whether MARCH1-mediated regulation occurs in non-cancer tissues unknown\", \"Single-lab study\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"No high-resolution structure of SLC25A17 exists, and the molecular basis for its substrate selectivity among CoA, FAD, NAD+, and their exchange partners remains unresolved; whether SLC25A17 deficiency underlies a human Mendelian peroxisomal disorder has not been established.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No crystal or cryo-EM structure\", \"No human disease-causing mutations reported\", \"Tissue-specific functions beyond liver and lung adenocarcinoma unexplored\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [2, 3, 4]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005777\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1430728\", \"supporting_discovery_ids\": [3, 4, 5]},\n      {\"term_id\": \"R-HSA-382551\", \"supporting_discovery_ids\": [2, 3]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\n      \"PEX3\",\n      \"MARCH1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}