{"gene":"PEX3","run_date":"2026-06-10T05:19:53","timeline":{"discoveries":[{"year":2004,"finding":"PEX3 functions as a docking factor for PEX19 at the peroxisomal membrane: PEX3 is required for PEX19 to dock at peroxisomes, interacts specifically with the docking domain of PEX19, and is sufficient to dock PEX19 at heterologous organelles. PEX3 binds PEX19 via a conserved motif essential for docking activity. Transient inhibition of PEX3 abrogates class I PMP import but has no effect on class II PMP import or peroxisomal matrix protein import.","method":"Co-immunoprecipitation, heterologous organelle docking assay, transient inhibition with dominant-negative constructs, class I vs. class II PMP import assays","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — reciprocal functional and binding assays across multiple orthogonal methods, replicated in subsequent studies","pmids":["15007061"],"is_preprint":false},{"year":1999,"finding":"Human PEX3 is an integral peroxisomal membrane protein with the N-terminus inside the peroxisome and C-terminus facing the cytoplasm. The N-terminal 33 amino acids are necessary and sufficient to direct PEX3 to peroxisomes. PEX19 interacts with PEX3 as shown by mammalian two-hybrid assay and co-immunoprecipitation of in vitro translated proteins.","method":"Immunofluorescence microscopy with N- and C-terminal tagged constructs, GFP fusion truncation analysis, mammalian two-hybrid assay, co-immunoprecipitation of in vitro translated proteins","journal":"European journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal methods (topology mapping, truncation analysis, two-hybrid, Co-IP) in one study, replicated by subsequent structural and FRET studies","pmids":["10430017"],"is_preprint":false},{"year":2000,"finding":"Inactivating mutations in human PEX3 cause Zellweger syndrome, abrogate peroxisome membrane synthesis, and result in reduced abundance or mislocalization of PMPs to mitochondria. Inhibition of COPI function by brefeldin A and inhibition of COPII-dependent traffic by dominant-negative SAR1 mutant both fail to block PEX3 transport to peroxisomes or PEX3-mediated peroxisome biogenesis, indicating PEX3 targeting and peroxisome membrane synthesis occur independently of COPI and COPII.","method":"Brefeldin A treatment, dominant-negative SAR1 expression, fluorescence microscopy, immunoblotting","journal":"The Journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Strong — two orthogonal inhibition approaches (BFA and dominant-negative SAR1) with functional readouts, replicated conceptually across multiple labs","pmids":["10871277"],"is_preprint":false},{"year":2010,"finding":"Crystal structure of the cytosolic domain of human PEX3 in complex with a PEX19-derived peptide reveals that PEX3 adopts a novel large helical bundle fold. A hydrophobic groove at the membrane-distal end of PEX3 engages the PEX19 peptide with nanomolar affinity. Mutagenesis identifies phenylalanine 29 in PEX19 as critical for this interaction. Key PEX3 residues are highly conserved across species.","method":"X-ray crystallography, surface plasmon resonance/binding affinity measurement, site-directed mutagenesis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Strong — crystal structure with mutagenesis validation, replicated mechanistically by follow-up mutagenesis study","pmids":["20554521"],"is_preprint":false},{"year":2012,"finding":"In S. cerevisiae, Pex3 recruits the pexophagy receptor Atg36 to the peroxisomal membrane. pex3 alleles blocked specifically in pexophagy cannot recruit Atg36. When Pex3 is redirected to mitochondria, Atg36 also localizes there and restores mitophagy in cells lacking Atg32. Atg36 binds Atg8 and the autophagy adaptor Atg11.","method":"Genetic isolation of pex3 alleles, fluorescence microscopy, epistasis analysis, subcellular re-targeting experiments","journal":"The EMBO journal","confidence":"High","confidence_rationale":"Tier 2 / Strong — specific pex3 alleles, heterologous organelle targeting, epistasis with multiple mutants; replicated by subsequent pexophagy studies","pmids":["22643220"],"is_preprint":false},{"year":2012,"finding":"Mutations in the PEX19-binding region of PEX3 reduce affinity for PEX19 and destabilize PEX3. A hydrophobic groove near the base of PEX3 is required for peroxisomal membrane protein insertion and maturation of preperoxisomes. An acidic cluster on PEX3 surface does not appear to be functionally relevant.","method":"Site-directed mutagenesis, biochemical binding assays, functional peroxisome biogenesis assays in peroxisome-deficient cells","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1 / Moderate — mutagenesis of crystallographically identified residues with multiple orthogonal biochemical and functional assays, single lab","pmids":["22624858"],"is_preprint":false},{"year":2003,"finding":"FRET imaging shows that the main intracellular site of PEX3-PEX19 interaction is the peroxisome. PEX3 deletion proteins lacking the N-terminal peroxisomal targeting sequence mislocalize to the cytoplasm, and those lacking the PEX19-binding domain (C-terminal half) mislocalize to mitochondria; neither interacts with PEX19.","method":"FRET imaging (EYFP/ECFP fusion proteins), donor fluorescence photobleaching, transfection of PEX3- and PEX19-deficient Zellweger patient fibroblasts","journal":"European journal of cell biology","confidence":"High","confidence_rationale":"Tier 2 / Moderate — live-cell FRET with quantification and domain deletion analysis, functional rescue in patient cells","pmids":["12924628"],"is_preprint":false},{"year":2014,"finding":"PEX3 overexpression in mammalian cells induces peroxisome ubiquitination, clustering, and lysosomal degradation via ubiquitin- and NBR1-mediated pexophagy. Peroxisome targeting of PEX3 is essential for this degradation pathway. SQSTM1/p62 is required only for clustering, not degradation. A PEX3 mutant with all lysine and cysteine residues substituted still induces peroxisome ubiquitination, indicating ubiquitination of PEX3 itself is dispensable and an unidentified peroxisomal protein is ubiquitinated.","method":"PEX3 overexpression, siRNA knockdown of NBR1 and p62, autophagy inhibitor treatment, fluorescence microscopy, lysine/cysteine mutagenesis","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function (siRNA) and mutagenesis with specific phenotypic readouts, single lab","pmids":["25007327"],"is_preprint":false},{"year":2015,"finding":"In P. pastoris, Pex3 activates the pexophagy receptor Atg30 by promoting its phosphorylation (a prerequisite for Atg30-Atg11 interaction) and by facilitating recruitment of Atg11 to the receptor-protein complex. Pex3 thus has a role beyond simple Atg30 docking, directly regulating pexophagy initiation.","method":"Binding site mapping by mutagenesis, phosphorylation assays, Atg11 recruitment assays","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional mutagenesis and biochemical assays, single lab","pmids":["25694426"],"is_preprint":false},{"year":2013,"finding":"Pex3 is a type III peroxisomal membrane protein that is inserted into the ER membrane and sorted via an ER subdomain (peroxisomal ER, pER) to peroxisomes. The N-terminal 17-amino acid segment of Pex3 contains two redundant signals sufficient for sorting to the pER. Subsequent transport to peroxisomes requires the Pex3 transmembrane segment. This intra-ER sorting mechanism is conserved in human and Drosophila Pex3.","method":"Chimeric protein construction (Pex3/Sec66 fusions), fluorescence microscopy in yeast and Drosophila S2R+ cells, domain swap analysis","journal":"Biology open","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — chimeric protein dissection with orthologous validation across species, single lab","pmids":["23951409"],"is_preprint":false},{"year":2015,"finding":"Human PEX3 inserts co-translationally into the mammalian ER via the Sec61 translocon. The N-terminal transmembrane segment of ribosome-bound PEX3 is recognized by the signal recognition particle (SRP). PEX3 then exits the ER via budding vesicles in an ATP-dependent process.","method":"Photocrosslinking, fluorescence spectroscopy of ribosome-nascent chain complexes, biochemical ER exit assay (ATP-dependence)","journal":"Traffic (Copenhagen, Denmark)","confidence":"High","confidence_rationale":"Tier 1 / Moderate — photocrosslinking and fluorescence spectroscopy with biochemical functional validation, multiple orthogonal methods in one study","pmids":["26572236"],"is_preprint":false},{"year":2006,"finding":"Upon reintroduction of Pex3p in H. polymorpha pex3 cells, Pex3-GFP initially localizes to the endoplasmic reticulum and nuclear envelope, then to a single developing peroxisome that multiplies by division. Fractionation confirms a small amount of ER/nuclear envelope marker in peroxisomes at the early stage, supporting a role for the ER/nuclear envelope in peroxisome reassembly from Pex3.","method":"Inducible GFP-Pex3 expression, live fluorescence microscopy, subcellular fractionation","journal":"FEMS yeast research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live imaging with inducible system plus biochemical fractionation, single lab","pmids":["16487342"],"is_preprint":false},{"year":2014,"finding":"Pex3 is not required for formation of peroxisomal membrane structures in yeast pex3 mutants; preperoxisomal vesicles containing Pex13, Pex14, Pex8, and alcohol oxidase exist in pex3 cells. When Pex3 is reintroduced, it sorts to these preperoxisomal structures (not to the ER de novo), and they mature into normal peroxisomes.","method":"Fluorescence microscopy, fractionation, double deletion (pex3 atg1) analysis to prevent autophagic degradation of vesicles","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple microscopy and genetic approaches, contradicts earlier ER-only de novo model; single lab","pmids":["24590171"],"is_preprint":false},{"year":2014,"finding":"PEX16 mediates the peroxisomal trafficking of PEX3 (and PMP34) via the ER, suggesting that PEX16 is required for ER-to-peroxisome transport of PEX3 and that the ER constitutively provides membrane proteins to pre-existing peroxisomes.","method":"ER-targeted PEX3 (ssPEX3) construct, quantitative time-lapse fluorescence microscopy, PEX16 depletion/overexpression","journal":"Journal of cell science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — live-cell quantitative imaging with genetic perturbation of PEX16, single lab","pmids":["25002403"],"is_preprint":false},{"year":2009,"finding":"In Yarrowia lipolytica, Pex3p and Pex3Bp function as peroxisomal receptors for class V myosin (Myo2p equivalent) through direct interaction with the myosin globular tail, mediating peroxisome inheritance. Cells lacking Pex3Bp retain peroxisomes in the mother cell; overexpression of Pex3Bp or Pex3p causes peroxisomes to transfer en masse to the bud.","method":"Direct interaction assay (globular tail binding), overexpression and deletion genetics, fluorescence microscopy of peroxisome inheritance","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct binding assay and epistasis with quantitative inheritance phenotype, single lab","pmids":["19822674"],"is_preprint":false},{"year":2009,"finding":"The cytosolic domain of human PEX3 binds membrane lipids: a recombinant cytosolic domain of PEX3 interacts with liposomes, inducing their flocculation or partial solubilization, and precipitates in the presence of mild detergents.","method":"Recombinant protein purification, lipid-binding assays with liposomes, detergent precipitation","journal":"Biochimica et biophysica acta","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single in vitro assay, functional consequence not established, single lab","pmids":["19715730"],"is_preprint":false},{"year":2018,"finding":"In P. pastoris, Pex3 and Atg37 compete for overlapping binding sites in the middle domain of Atg30. Atg37 depends on Pex3 for its peroxisomal membrane localization. Pex3 binding to Atg30 negatively regulates Atg30 phosphorylation by Hrr25 kinase, while Atg37 binding positively regulates it. The binding of Pex3 and Atg37 to Atg30 is mutually exclusive within the middle domain.","method":"Binding competition assays, phosphorylation assays, fluorescence microscopy for localization dependence","journal":"Autophagy","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple binding and phosphorylation assays with mutational dissection, single lab","pmids":["29260977"],"is_preprint":false},{"year":2018,"finding":"Pex3 accumulates in patches at peroxisome-vacuole contact sites in H. polymorpha under peroxisome proliferation conditions (methanol medium). Overproduction of Pex3 at non-proliferating conditions also induces peroxisome-vacuole associations, suggesting a direct role for Pex3 in forming a novel peroxisome-vacuole contact site involved in membrane growth.","method":"Electron microscopy, fluorescence microscopy, Pex3 overexpression","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — localization data by microscopy with overexpression, no mechanistic dissection, single lab","pmids":["30595161"],"is_preprint":false},{"year":2020,"finding":"In S. cerevisiae, Pex3 directly promotes Atg36 phosphorylation by the Hrr25 kinase: Atg36 phosphorylation is abolished in cells lacking Pex3 or expressing a Pex3 mutant defective in Atg36 interaction; recombinant Pex3 directly promotes Atg36 phosphorylation by Hrr25 in vitro; and Pex3 enhances the Atg36-Hrr25 interaction (shown by Co-IP). Pex3 binding also protects Atg36 from proteasomal degradation.","method":"In vitro phosphorylation assay with recombinant proteins, co-immunoprecipitation, pex3 deletion and point mutant analysis","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution with recombinant proteins plus Co-IP and genetic verification, single lab with multiple orthogonal methods","pmids":["32958557"],"is_preprint":false},{"year":2020,"finding":"Inp1 acts as the plasma membrane-peroxisome (PM-PER) tether via an N-terminal domain that binds PI(4,5)P2 and a C-terminal Pex3-binding domain, forming a bridge between the peroxisomal membrane (via Pex3) and the plasma membrane. Expression of artificial PM-PER tethers restores peroxisome retention in inp1Δ cells.","method":"Artificial tether rescue assay, domain deletion and localization studies, PI(4,5)P2-binding assay","journal":"The Journal of cell biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — artificial tether rescue plus binding domain mapping with multiple approaches, single lab","pmids":["32970792"],"is_preprint":false},{"year":2014,"finding":"PEX19 remains highly flexible during interaction with PEX3 (as determined by hydrogen exchange mass spectrometry). The N-terminus of PEX19 initiates binding to PEX3. A short stretch in PEX19 (F64-L74) and regions at the N- and C-terminus become shielded from hydrogen exchange upon complex formation. PEX3 becomes more protected in its PEX19-binding groove with only small changes elsewhere. PEX3 is stabilized by PEX19 binding, preventing PEX3 aggregation.","method":"Hydrogen exchange mass spectrometry (HX-MS) in vitro","journal":"PloS one","confidence":"Medium","confidence_rationale":"Tier 1 / Weak — rigorous biophysical method but single lab, in vitro only","pmids":["25062251"],"is_preprint":false},{"year":2019,"finding":"Trypanosomal Pex3 localizes to glycosomes and directly interacts with Pex19. Depletion of Pex3 by RNAi leads to mislocalization of glycosomal proteins to the cytosol, reduced glycosome numbers, and parasite death, establishing Pex3 as an essential master regulator of glycosome biogenesis in trypanosomes.","method":"Fluorescence microscopy, biochemical fractionation, RNAi depletion, co-immunoprecipitation","journal":"Life science alliance","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (microscopy, fractionation, RNAi, Co-IP), replicated independently in a second trypanosome study","pmids":["31341002"],"is_preprint":false},{"year":2019,"finding":"Trypanosomal PEX3 directly interacts with PEX19 (confirmed by co-immunoprecipitation). RNAi knockdown of TbPEX3 causes mislocalization of glycosomal membrane and matrix proteins to the cytosol and severe growth defect. The PEX3-PEX19 interface shows structural differences from human PEX3-PEX19 interface.","method":"Co-immunoprecipitation, RNAi knockdown, fluorescence microscopy, secondary structure homology modeling","journal":"Biochimica et biophysica acta. Molecular cell research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — Co-IP and RNAi with functional readouts, replicated independently in second trypanosome study","pmids":["31369765"],"is_preprint":false},{"year":2024,"finding":"PEX3 promotes myocardial regenerative repair by affecting plasmalogen metabolism. Cardiomyocyte-specific PEX3 knockout disrupts redox homeostasis and endogenous proliferation/development. Mechanistically, PEX3-regulated plasmalogen activates the AKT/GSK3β signaling pathway via plasma membrane localization of ITGB3.","method":"Cardiomyocyte-specific Pex3 knockout mice, lipid metabolomics, myocardium-targeted intervention, AKT/GSK3β pathway analysis","journal":"Communications biology","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — conditional knockout with lipidomics and signaling pathway readout, single lab","pmids":["38951640"],"is_preprint":false},{"year":2023,"finding":"Germ cell-specific deletion of Pex3 in mice causes male sterility: destruction of intercellular bridges between spermatids and formation of multinucleated giant cells. Sertoli cell-specific deletion does not affect spermatogenesis. Proteomic analysis reveals defective expression of peroxisomal and spermiogenesis-related proteins in Pex3-deleted spermatids.","method":"Conditional knockout (germ cell- and Sertoli cell-specific), fertility analysis, proteomics, fluorescence microscopy","journal":"Journal of biomedical research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — cell-type-specific conditional knockout with defined phenotypic and proteomic readout, single lab","pmids":["38062668"],"is_preprint":false},{"year":2025,"finding":"High levels of Pex3 in S. cerevisiae induce formation of peroxisome clusters surrounded by lipid droplets, mediated by peroxisome-peroxisome and peroxisome-lipid droplet contact sites. The cytosolic domain of Pex3 binds peroxisomes directly, suggesting a role in homotypic contact site formation. This clustering is independent of Pex3 partners Pex19, Inp1, and Atg36. Lipid droplet-peroxisome contact sites require the lipid droplet-localized triacylglycerol lipase Tgl4. Overexpression of Pex3 in Drosophila similarly alters peroxisome and lipid droplet morphology.","method":"Pex3 overexpression in yeast and Drosophila, fluorescence microscopy, cytosolic domain binding assay, epistasis with pex19, inp1, atg36 deletions","journal":"Scientific reports","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple genetic epistasis tests and direct binding assay with cross-species validation, single lab","pmids":["40628847"],"is_preprint":false},{"year":2025,"finding":"In yeast, Pex3 binding partners Pex19, Atg30, and Inp1 compete for overlapping interaction regions on Pex3 (confirmed by crystal structure of H. polymorpha Pex3-Pex19 complex and AlphaFold2 predictions). Overexpression of any binding partner affects peroxisomal processes, with the level of overexpression being the primary determinant of competition.","method":"Crystal structure of H. polymorpha Pex3-Pex19 complex, AlphaFold2 modeling, overexpression competition assays, functional peroxisome assays","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — crystal structure plus functional competition assays, single lab","pmids":["40847603"],"is_preprint":false},{"year":2025,"finding":"Newly synthesized Pex15 (a tail-anchored peroxisomal membrane protein) is targeted to peroxisomes primarily via the Pex19- and Pex3-dependent pathway. Mistargeted Pex15 on the mitochondrial outer membrane is extracted by Msp1 and returned to peroxisomes via the Pex19-Pex3 pathway. Peroxisome-resident Pex15 is also continuously extracted by peroxisomal Msp1 and re-targeted via Pex19-Pex3.","method":"Genetic epistasis (msp1, pex19, pex3 deletions), fluorescence microscopy of Pex15 localization, functional import assays","journal":"The FEBS journal","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — epistasis with multiple deletion strains and localization studies, single lab","pmids":["40344504"],"is_preprint":false},{"year":2021,"finding":"Depletion of PEX3 from human HeLa cells (quantitative proteomics) negatively affects 12 peroxisomal proteins and two hairpin proteins of the ER, confirming PEX19/PEX3 as the pathway for these two client classes. PEX3 deficiency also negatively affects 14 collagen-related proteins with signal peptides or N-terminal transmembrane helices.","method":"Label-free quantitative mass spectrometry of total proteome in PEX3-depleted HeLa cells and PEX3-deficient Zellweger fibroblasts, differential protein abundance analysis","journal":"International journal of molecular sciences","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — quantitative proteomics across two cellular models, single lab; functional mechanism not fully resolved for collagen clients","pmids":["34884833"],"is_preprint":false}],"current_model":"PEX3 is an integral peroxisomal membrane protein (N-terminus luminal, C-terminus cytoplasmic) that inserts co-translationally into the ER via the Sec61 translocon, exits in ATP-dependent budding vesicles, and serves as the membrane docking factor for the cytosolic PMP import receptor PEX19—binding it via a conserved hydrophobic groove (structurally resolved by X-ray crystallography)—to mediate class I peroxisomal membrane protein import; it also recruits pexophagy receptors (Atg36 in S. cerevisiae, Atg30 in P. pastoris) to peroxisomes and directly promotes their phosphorylation by the Hrr25 kinase to initiate selective autophagic degradation of peroxisomes, while additionally functioning in peroxisome inheritance (as a myosin V receptor), retention (via Inp1 bridging to the plasma membrane PI(4,5)P2), contact site formation with vacuoles and lipid droplets, and—in mammals—regulating plasmalogen metabolism and the AKT/GSK3β/ITGB3 signaling axis relevant to myocardial repair and spermiogenesis."},"narrative":{"mechanistic_narrative":"PEX3 is an integral peroxisomal membrane protein that serves as the central membrane platform for peroxisomal membrane protein (PMP) import, peroxisome biogenesis, and the regulated turnover, inheritance, and contact-site organization of peroxisomes [PMID:15007061, PMID:10430017]. It adopts a single-spanning topology with an N-terminal luminal segment whose first ~33 residues are sufficient for peroxisomal targeting and a cytoplasmic C-terminal domain [PMID:10430017]; this cytosolic domain folds into a novel large helical bundle that presents a membrane-distal hydrophobic groove engaging the cytosolic import receptor PEX19 with nanomolar affinity through a critical PEX19 phenylalanine (F29) [PMID:20554521]. Acting as the membrane docking factor for PEX19, PEX3 is required and sufficient to dock PEX19 at organelles and to drive class I PMP import while leaving matrix and class II import intact [PMID:15007061, PMID:12924628], with reciprocal stabilization of the otherwise aggregation-prone PEX3 by PEX19 [PMID:25062251]. PEX3 itself reaches peroxisomes through the ER: it inserts co-translationally via the SRP/Sec61 route and exits in ATP-dependent budding vesicles [PMID:26572236], using redundant N-terminal sorting signals and its transmembrane segment for intra-ER routing [PMID:23951409], a step dependent on PEX16 [PMID:25002403]; reintroduction of PEX3 can both reassemble peroxisomes via the ER and mature pre-existing preperoxisomal vesicles [PMID:16487342, PMID:24590171]. Beyond biogenesis, PEX3 nucleates selective autophagic degradation of peroxisomes by recruiting and activating pexophagy receptors (Atg36 in S. cerevisiae, Atg30 in P. pastoris) and directly promoting their phosphorylation by Hrr25 kinase to initiate pexophagy [PMID:22643220, PMID:25694426, PMID:32958557], a function balanced against PEX3 import partners that compete for overlapping surfaces on PEX3 and on the receptor [PMID:29260977, PMID:40847603]. PEX3 additionally controls peroxisome inheritance as a class V myosin receptor [PMID:19822674], retention via Inp1 bridging to plasma-membrane PI(4,5)P2 [PMID:32970792], and contact-site formation with lipid droplets [PMID:40628847]. Inactivating PEX3 mutations cause Zellweger syndrome by abolishing peroxisome membrane synthesis and mislocalizing PMPs [PMID:10871277], and in mammals PEX3 regulates plasmalogen metabolism that activates AKT/GSK3β/ITGB3 signaling in myocardial repair and is required for spermiogenesis [PMID:38951640, PMID:38062668].","teleology":[{"year":1999,"claim":"Established the basic identity and topology of PEX3 as an integral peroxisomal membrane protein and its physical link to PEX19, defining the molecular entity to be studied.","evidence":"Topology mapping, GFP truncation analysis, mammalian two-hybrid, and Co-IP of in vitro translated proteins","pmids":["10430017"],"confidence":"High","gaps":["Functional role of the PEX3-PEX19 interaction not yet defined","Mechanism of N-terminal targeting unresolved"]},{"year":2000,"claim":"Showed PEX3 is essential for peroxisome membrane synthesis and that its trafficking is independent of classical COPI/COPII secretory routes, while linking PEX3 loss to human disease.","evidence":"Brefeldin A, dominant-negative SAR1, and microscopy in Zellweger patient cells","pmids":["10871277"],"confidence":"High","gaps":["Actual trafficking route of PEX3 left unspecified","Which PMPs are mislocalized and why was not fully resolved"]},{"year":2003,"claim":"Localized the PEX3-PEX19 interaction in living cells to the peroxisome and mapped targeting versus binding domains, distinguishing PEX3's two functional modules.","evidence":"Live-cell FRET imaging and domain-deletion rescue in patient fibroblasts","pmids":["12924628"],"confidence":"High","gaps":["Structural basis of binding not yet known","Dynamics of the docking cycle unresolved"]},{"year":2004,"claim":"Defined PEX3 as the membrane docking factor that is necessary and sufficient to recruit PEX19 and to drive class I but not class II PMP import, establishing pathway selectivity.","evidence":"Co-IP, heterologous organelle docking, dominant-negative inhibition, class I/II import assays","pmids":["15007061"],"confidence":"High","gaps":["Molecular interface not defined at residue level","How docking converts to membrane insertion unclear"]},{"year":2010,"claim":"Provided the atomic-resolution mechanism of PEX19 recognition, revealing a novel helical bundle fold and a hydrophobic groove engaging PEX19 F29 with nanomolar affinity.","evidence":"X-ray crystallography of the PEX3 cytosolic domain with PEX19 peptide plus binding and mutagenesis","pmids":["20554521"],"confidence":"High","gaps":["Crystallized only a PEX19-derived peptide, not full-length PEX19","Membrane-embedded context not captured"]},{"year":2012,"claim":"Functionally validated the crystallographically identified groove as required for PMP insertion and preperoxisome maturation, and discovered PEX3's role in recruiting the pexophagy receptor.","evidence":"Mutagenesis of groove residues with biogenesis assays; pexophagy-specific pex3 alleles and Atg36 mislocalization in yeast","pmids":["22624858","22643220"],"confidence":"High","gaps":["How a single groove serves both PEX19 docking and Atg36 recruitment unclear","Mechanism of Atg36 activation not yet defined"]},{"year":2013,"claim":"Resolved how PEX3 reaches peroxisomes via the ER, identifying redundant N-terminal sorting signals and a transmembrane-dependent exit step conserved across species.","evidence":"Pex3/Sec66 chimeras and domain swaps in yeast and Drosophila cells","pmids":["23951409"],"confidence":"Medium","gaps":["Identity of the ER subdomain machinery unresolved","Vesicle budding factors not identified"]},{"year":2014,"claim":"Refined the biogenesis model by showing preperoxisomal vesicles can form without PEX3 and that PEX3 sorts to and matures them, while PEX16 mediates ER-to-peroxisome PEX3 transport; also defined a mammalian pexophagy pathway and a myosin V receptor role.","evidence":"Microscopy/fractionation with pex3 atg1 double deletions; ssPEX3 time-lapse imaging with PEX16 perturbation; PEX3 overexpression with NBR1/p62 knockdown; myosin globular-tail binding in Y. lipolytica","pmids":["24590171","25002403","25007327","19822674"],"confidence":"Medium","gaps":["De novo versus preexisting-vesicle origin of peroxisomes still debated across systems","Ubiquitinated peroxisomal target in PEX3-driven pexophagy unidentified","Whether mammalian PEX3 acts as a myosin receptor untested"]},{"year":2015,"claim":"Defined the early secretory entry of PEX3 (SRP/Sec61 co-translational insertion, ATP-dependent ER exit) and showed PEX3 actively initiates pexophagy by promoting receptor phosphorylation rather than mere docking.","evidence":"Photocrosslinking and fluorescence spectroscopy of nascent chains plus ER exit assay; binding/phosphorylation/Atg11 recruitment assays in P. pastoris","pmids":["26572236","25694426"],"confidence":"High","gaps":["Budding vesicle coat machinery unidentified","Kinase responsible for Atg30 phosphorylation not yet pinned in this study"]},{"year":2018,"claim":"Revealed competitive regulation of pexophagy through overlapping binding of Pex3 and Atg37 on Atg30, showing Pex3 negatively and Atg37 positively tune Hrr25 phosphorylation; also implicated Pex3 in peroxisome-vacuole contact sites.","evidence":"Binding competition and phosphorylation assays in P. pastoris; EM/fluorescence with Pex3 overexpression in H. polymorpha","pmids":["29260977","30595161"],"confidence":"Medium","gaps":["Contact-site role rests on overexpression microscopy without mechanistic dissection","How competing inputs are integrated to set pexophagy threshold unclear"]},{"year":2019,"claim":"Extended PEX3's PEX19-docking function to a divergent eukaryote, establishing Pex3 as essential master regulator of glycosome biogenesis in trypanosomes.","evidence":"RNAi depletion, fractionation, microscopy, and Co-IP in trypanosomes (two independent studies)","pmids":["31341002","31369765"],"confidence":"Medium","gaps":["Structural basis of the divergent trypanosomal interface not solved","Therapeutic exploitation untested"]},{"year":2020,"claim":"Reconstituted the catalytic role of Pex3 in pexophagy and resolved the molecular basis of peroxisome retention, showing Pex3 directly drives Hrr25 phosphorylation of Atg36 and bridges Inp1 to plasma-membrane PI(4,5)P2.","evidence":"In vitro phosphorylation with recombinant Pex3/Hrr25/Atg36 plus Co-IP and genetics; artificial PM-PER tether rescue with PI(4,5)P2 binding assays","pmids":["32958557","32970792"],"confidence":"High","gaps":["How Pex3 allosterically enhances the Atg36-Hrr25 reaction unresolved","Whether mammalian PEX3 uses an analogous retention tether unknown"]},{"year":2021,"claim":"Mapped the human PEX3-dependent clientele by proteomics, confirming peroxisomal and ER-hairpin clients and unexpectedly linking PEX3 deficiency to collagen-related proteins.","evidence":"Label-free quantitative proteomics in PEX3-depleted HeLa cells and Zellweger fibroblasts","pmids":["34884833"],"confidence":"Medium","gaps":["Mechanism connecting PEX3 to collagen-pathway clients unresolved","Direct versus indirect dependence not distinguished"]},{"year":2024,"claim":"Linked PEX3 to organ-level physiology, showing it shapes plasmalogen metabolism that activates AKT/GSK3β/ITGB3 signaling for myocardial regeneration and is required for spermiogenesis.","evidence":"Cardiomyocyte-specific and germ cell-specific Pex3 knockout mice with lipidomics, proteomics, and pathway analysis","pmids":["38951640","38062668"],"confidence":"Medium","gaps":["How plasmalogen changes mechanistically license ITGB3 membrane localization unclear","Whether spermatid defects are plasmalogen-dependent untested"]},{"year":2025,"claim":"Integrated PEX3 into a competitive partner network and contact-site biology, showing Pex19/Atg30/Inp1 compete for overlapping Pex3 surfaces, that Pex3 drives peroxisome-lipid droplet contacts, and that it cooperates in Msp1-mediated re-targeting of tail-anchored Pex15.","evidence":"H. polymorpha Pex3-Pex19 crystal structure with AlphaFold2 and overexpression competition; 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Study","date":"2025-09-12","source":"bioRxiv","url":"https://doi.org/10.1101/2025.09.08.25335383","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.13.612636","title":"An inhibitor targeting glycosome membrane biogenesis kills  <i>Leishmania</i>  parasites","date":"2024-09-14","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.13.612636","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2025.02.12.637848","title":"Pex30-dependent membrane contacts sites maintain ER lipid homeostasis","date":"2025-02-16","source":"bioRxiv","url":"https://doi.org/10.1101/2025.02.12.637848","citation_count":0,"is_preprint":true},{"pmid":null,"id":"bio_10.1101_2024.09.23.614586","title":"Genetic analysis of the X-linked Adrenoleukodystrophy  <i>ABCD1 gene</i>  in  <i>Drosophila</i>  uncovers a role in Peroxisomal dynamics","date":"2024-09-25","source":"bioRxiv","url":"https://doi.org/10.1101/2024.09.23.614586","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":31901,"output_tokens":7641,"usd":0.105159,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":16754,"output_tokens":5364,"usd":0.108935,"stage2_stop_reason":"end_turn"},"total_usd":0.214094,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2004,\n      \"finding\": \"PEX3 functions as a docking factor for PEX19 at the peroxisomal membrane: PEX3 is required for PEX19 to dock at peroxisomes, interacts specifically with the docking domain of PEX19, and is sufficient to dock PEX19 at heterologous organelles. PEX3 binds PEX19 via a conserved motif essential for docking activity. Transient inhibition of PEX3 abrogates class I PMP import but has no effect on class II PMP import or peroxisomal matrix protein import.\",\n      \"method\": \"Co-immunoprecipitation, heterologous organelle docking assay, transient inhibition with dominant-negative constructs, class I vs. class II PMP import assays\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — reciprocal functional and binding assays across multiple orthogonal methods, replicated in subsequent studies\",\n      \"pmids\": [\"15007061\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 1999,\n      \"finding\": \"Human PEX3 is an integral peroxisomal membrane protein with the N-terminus inside the peroxisome and C-terminus facing the cytoplasm. The N-terminal 33 amino acids are necessary and sufficient to direct PEX3 to peroxisomes. PEX19 interacts with PEX3 as shown by mammalian two-hybrid assay and co-immunoprecipitation of in vitro translated proteins.\",\n      \"method\": \"Immunofluorescence microscopy with N- and C-terminal tagged constructs, GFP fusion truncation analysis, mammalian two-hybrid assay, co-immunoprecipitation of in vitro translated proteins\",\n      \"journal\": \"European journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal methods (topology mapping, truncation analysis, two-hybrid, Co-IP) in one study, replicated by subsequent structural and FRET studies\",\n      \"pmids\": [\"10430017\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2000,\n      \"finding\": \"Inactivating mutations in human PEX3 cause Zellweger syndrome, abrogate peroxisome membrane synthesis, and result in reduced abundance or mislocalization of PMPs to mitochondria. Inhibition of COPI function by brefeldin A and inhibition of COPII-dependent traffic by dominant-negative SAR1 mutant both fail to block PEX3 transport to peroxisomes or PEX3-mediated peroxisome biogenesis, indicating PEX3 targeting and peroxisome membrane synthesis occur independently of COPI and COPII.\",\n      \"method\": \"Brefeldin A treatment, dominant-negative SAR1 expression, fluorescence microscopy, immunoblotting\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — two orthogonal inhibition approaches (BFA and dominant-negative SAR1) with functional readouts, replicated conceptually across multiple labs\",\n      \"pmids\": [\"10871277\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"Crystal structure of the cytosolic domain of human PEX3 in complex with a PEX19-derived peptide reveals that PEX3 adopts a novel large helical bundle fold. A hydrophobic groove at the membrane-distal end of PEX3 engages the PEX19 peptide with nanomolar affinity. Mutagenesis identifies phenylalanine 29 in PEX19 as critical for this interaction. Key PEX3 residues are highly conserved across species.\",\n      \"method\": \"X-ray crystallography, surface plasmon resonance/binding affinity measurement, site-directed mutagenesis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — crystal structure with mutagenesis validation, replicated mechanistically by follow-up mutagenesis study\",\n      \"pmids\": [\"20554521\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"In S. cerevisiae, Pex3 recruits the pexophagy receptor Atg36 to the peroxisomal membrane. pex3 alleles blocked specifically in pexophagy cannot recruit Atg36. When Pex3 is redirected to mitochondria, Atg36 also localizes there and restores mitophagy in cells lacking Atg32. Atg36 binds Atg8 and the autophagy adaptor Atg11.\",\n      \"method\": \"Genetic isolation of pex3 alleles, fluorescence microscopy, epistasis analysis, subcellular re-targeting experiments\",\n      \"journal\": \"The EMBO journal\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — specific pex3 alleles, heterologous organelle targeting, epistasis with multiple mutants; replicated by subsequent pexophagy studies\",\n      \"pmids\": [\"22643220\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Mutations in the PEX19-binding region of PEX3 reduce affinity for PEX19 and destabilize PEX3. A hydrophobic groove near the base of PEX3 is required for peroxisomal membrane protein insertion and maturation of preperoxisomes. An acidic cluster on PEX3 surface does not appear to be functionally relevant.\",\n      \"method\": \"Site-directed mutagenesis, biochemical binding assays, functional peroxisome biogenesis assays in peroxisome-deficient cells\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — mutagenesis of crystallographically identified residues with multiple orthogonal biochemical and functional assays, single lab\",\n      \"pmids\": [\"22624858\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2003,\n      \"finding\": \"FRET imaging shows that the main intracellular site of PEX3-PEX19 interaction is the peroxisome. PEX3 deletion proteins lacking the N-terminal peroxisomal targeting sequence mislocalize to the cytoplasm, and those lacking the PEX19-binding domain (C-terminal half) mislocalize to mitochondria; neither interacts with PEX19.\",\n      \"method\": \"FRET imaging (EYFP/ECFP fusion proteins), donor fluorescence photobleaching, transfection of PEX3- and PEX19-deficient Zellweger patient fibroblasts\",\n      \"journal\": \"European journal of cell biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell FRET with quantification and domain deletion analysis, functional rescue in patient cells\",\n      \"pmids\": [\"12924628\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PEX3 overexpression in mammalian cells induces peroxisome ubiquitination, clustering, and lysosomal degradation via ubiquitin- and NBR1-mediated pexophagy. Peroxisome targeting of PEX3 is essential for this degradation pathway. SQSTM1/p62 is required only for clustering, not degradation. A PEX3 mutant with all lysine and cysteine residues substituted still induces peroxisome ubiquitination, indicating ubiquitination of PEX3 itself is dispensable and an unidentified peroxisomal protein is ubiquitinated.\",\n      \"method\": \"PEX3 overexpression, siRNA knockdown of NBR1 and p62, autophagy inhibitor treatment, fluorescence microscopy, lysine/cysteine mutagenesis\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function (siRNA) and mutagenesis with specific phenotypic readouts, single lab\",\n      \"pmids\": [\"25007327\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"In P. pastoris, Pex3 activates the pexophagy receptor Atg30 by promoting its phosphorylation (a prerequisite for Atg30-Atg11 interaction) and by facilitating recruitment of Atg11 to the receptor-protein complex. Pex3 thus has a role beyond simple Atg30 docking, directly regulating pexophagy initiation.\",\n      \"method\": \"Binding site mapping by mutagenesis, phosphorylation assays, Atg11 recruitment assays\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional mutagenesis and biochemical assays, single lab\",\n      \"pmids\": [\"25694426\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"Pex3 is a type III peroxisomal membrane protein that is inserted into the ER membrane and sorted via an ER subdomain (peroxisomal ER, pER) to peroxisomes. The N-terminal 17-amino acid segment of Pex3 contains two redundant signals sufficient for sorting to the pER. Subsequent transport to peroxisomes requires the Pex3 transmembrane segment. This intra-ER sorting mechanism is conserved in human and Drosophila Pex3.\",\n      \"method\": \"Chimeric protein construction (Pex3/Sec66 fusions), fluorescence microscopy in yeast and Drosophila S2R+ cells, domain swap analysis\",\n      \"journal\": \"Biology open\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — chimeric protein dissection with orthologous validation across species, single lab\",\n      \"pmids\": [\"23951409\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"Human PEX3 inserts co-translationally into the mammalian ER via the Sec61 translocon. The N-terminal transmembrane segment of ribosome-bound PEX3 is recognized by the signal recognition particle (SRP). PEX3 then exits the ER via budding vesicles in an ATP-dependent process.\",\n      \"method\": \"Photocrosslinking, fluorescence spectroscopy of ribosome-nascent chain complexes, biochemical ER exit assay (ATP-dependence)\",\n      \"journal\": \"Traffic (Copenhagen, Denmark)\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — photocrosslinking and fluorescence spectroscopy with biochemical functional validation, multiple orthogonal methods in one study\",\n      \"pmids\": [\"26572236\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2006,\n      \"finding\": \"Upon reintroduction of Pex3p in H. polymorpha pex3 cells, Pex3-GFP initially localizes to the endoplasmic reticulum and nuclear envelope, then to a single developing peroxisome that multiplies by division. Fractionation confirms a small amount of ER/nuclear envelope marker in peroxisomes at the early stage, supporting a role for the ER/nuclear envelope in peroxisome reassembly from Pex3.\",\n      \"method\": \"Inducible GFP-Pex3 expression, live fluorescence microscopy, subcellular fractionation\",\n      \"journal\": \"FEMS yeast research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live imaging with inducible system plus biochemical fractionation, single lab\",\n      \"pmids\": [\"16487342\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"Pex3 is not required for formation of peroxisomal membrane structures in yeast pex3 mutants; preperoxisomal vesicles containing Pex13, Pex14, Pex8, and alcohol oxidase exist in pex3 cells. When Pex3 is reintroduced, it sorts to these preperoxisomal structures (not to the ER de novo), and they mature into normal peroxisomes.\",\n      \"method\": \"Fluorescence microscopy, fractionation, double deletion (pex3 atg1) analysis to prevent autophagic degradation of vesicles\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple microscopy and genetic approaches, contradicts earlier ER-only de novo model; single lab\",\n      \"pmids\": [\"24590171\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PEX16 mediates the peroxisomal trafficking of PEX3 (and PMP34) via the ER, suggesting that PEX16 is required for ER-to-peroxisome transport of PEX3 and that the ER constitutively provides membrane proteins to pre-existing peroxisomes.\",\n      \"method\": \"ER-targeted PEX3 (ssPEX3) construct, quantitative time-lapse fluorescence microscopy, PEX16 depletion/overexpression\",\n      \"journal\": \"Journal of cell science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — live-cell quantitative imaging with genetic perturbation of PEX16, single lab\",\n      \"pmids\": [\"25002403\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"In Yarrowia lipolytica, Pex3p and Pex3Bp function as peroxisomal receptors for class V myosin (Myo2p equivalent) through direct interaction with the myosin globular tail, mediating peroxisome inheritance. Cells lacking Pex3Bp retain peroxisomes in the mother cell; overexpression of Pex3Bp or Pex3p causes peroxisomes to transfer en masse to the bud.\",\n      \"method\": \"Direct interaction assay (globular tail binding), overexpression and deletion genetics, fluorescence microscopy of peroxisome inheritance\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct binding assay and epistasis with quantitative inheritance phenotype, single lab\",\n      \"pmids\": [\"19822674\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"The cytosolic domain of human PEX3 binds membrane lipids: a recombinant cytosolic domain of PEX3 interacts with liposomes, inducing their flocculation or partial solubilization, and precipitates in the presence of mild detergents.\",\n      \"method\": \"Recombinant protein purification, lipid-binding assays with liposomes, detergent precipitation\",\n      \"journal\": \"Biochimica et biophysica acta\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single in vitro assay, functional consequence not established, single lab\",\n      \"pmids\": [\"19715730\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"In P. pastoris, Pex3 and Atg37 compete for overlapping binding sites in the middle domain of Atg30. Atg37 depends on Pex3 for its peroxisomal membrane localization. Pex3 binding to Atg30 negatively regulates Atg30 phosphorylation by Hrr25 kinase, while Atg37 binding positively regulates it. The binding of Pex3 and Atg37 to Atg30 is mutually exclusive within the middle domain.\",\n      \"method\": \"Binding competition assays, phosphorylation assays, fluorescence microscopy for localization dependence\",\n      \"journal\": \"Autophagy\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple binding and phosphorylation assays with mutational dissection, single lab\",\n      \"pmids\": [\"29260977\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Pex3 accumulates in patches at peroxisome-vacuole contact sites in H. polymorpha under peroxisome proliferation conditions (methanol medium). Overproduction of Pex3 at non-proliferating conditions also induces peroxisome-vacuole associations, suggesting a direct role for Pex3 in forming a novel peroxisome-vacuole contact site involved in membrane growth.\",\n      \"method\": \"Electron microscopy, fluorescence microscopy, Pex3 overexpression\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — localization data by microscopy with overexpression, no mechanistic dissection, single lab\",\n      \"pmids\": [\"30595161\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"In S. cerevisiae, Pex3 directly promotes Atg36 phosphorylation by the Hrr25 kinase: Atg36 phosphorylation is abolished in cells lacking Pex3 or expressing a Pex3 mutant defective in Atg36 interaction; recombinant Pex3 directly promotes Atg36 phosphorylation by Hrr25 in vitro; and Pex3 enhances the Atg36-Hrr25 interaction (shown by Co-IP). Pex3 binding also protects Atg36 from proteasomal degradation.\",\n      \"method\": \"In vitro phosphorylation assay with recombinant proteins, co-immunoprecipitation, pex3 deletion and point mutant analysis\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution with recombinant proteins plus Co-IP and genetic verification, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"32958557\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Inp1 acts as the plasma membrane-peroxisome (PM-PER) tether via an N-terminal domain that binds PI(4,5)P2 and a C-terminal Pex3-binding domain, forming a bridge between the peroxisomal membrane (via Pex3) and the plasma membrane. Expression of artificial PM-PER tethers restores peroxisome retention in inp1Δ cells.\",\n      \"method\": \"Artificial tether rescue assay, domain deletion and localization studies, PI(4,5)P2-binding assay\",\n      \"journal\": \"The Journal of cell biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — artificial tether rescue plus binding domain mapping with multiple approaches, single lab\",\n      \"pmids\": [\"32970792\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2014,\n      \"finding\": \"PEX19 remains highly flexible during interaction with PEX3 (as determined by hydrogen exchange mass spectrometry). The N-terminus of PEX19 initiates binding to PEX3. A short stretch in PEX19 (F64-L74) and regions at the N- and C-terminus become shielded from hydrogen exchange upon complex formation. PEX3 becomes more protected in its PEX19-binding groove with only small changes elsewhere. PEX3 is stabilized by PEX19 binding, preventing PEX3 aggregation.\",\n      \"method\": \"Hydrogen exchange mass spectrometry (HX-MS) in vitro\",\n      \"journal\": \"PloS one\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Weak — rigorous biophysical method but single lab, in vitro only\",\n      \"pmids\": [\"25062251\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Trypanosomal Pex3 localizes to glycosomes and directly interacts with Pex19. Depletion of Pex3 by RNAi leads to mislocalization of glycosomal proteins to the cytosol, reduced glycosome numbers, and parasite death, establishing Pex3 as an essential master regulator of glycosome biogenesis in trypanosomes.\",\n      \"method\": \"Fluorescence microscopy, biochemical fractionation, RNAi depletion, co-immunoprecipitation\",\n      \"journal\": \"Life science alliance\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (microscopy, fractionation, RNAi, Co-IP), replicated independently in a second trypanosome study\",\n      \"pmids\": [\"31341002\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"Trypanosomal PEX3 directly interacts with PEX19 (confirmed by co-immunoprecipitation). RNAi knockdown of TbPEX3 causes mislocalization of glycosomal membrane and matrix proteins to the cytosol and severe growth defect. The PEX3-PEX19 interface shows structural differences from human PEX3-PEX19 interface.\",\n      \"method\": \"Co-immunoprecipitation, RNAi knockdown, fluorescence microscopy, secondary structure homology modeling\",\n      \"journal\": \"Biochimica et biophysica acta. Molecular cell research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — Co-IP and RNAi with functional readouts, replicated independently in second trypanosome study\",\n      \"pmids\": [\"31369765\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"PEX3 promotes myocardial regenerative repair by affecting plasmalogen metabolism. Cardiomyocyte-specific PEX3 knockout disrupts redox homeostasis and endogenous proliferation/development. Mechanistically, PEX3-regulated plasmalogen activates the AKT/GSK3β signaling pathway via plasma membrane localization of ITGB3.\",\n      \"method\": \"Cardiomyocyte-specific Pex3 knockout mice, lipid metabolomics, myocardium-targeted intervention, AKT/GSK3β pathway analysis\",\n      \"journal\": \"Communications biology\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — conditional knockout with lipidomics and signaling pathway readout, single lab\",\n      \"pmids\": [\"38951640\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2023,\n      \"finding\": \"Germ cell-specific deletion of Pex3 in mice causes male sterility: destruction of intercellular bridges between spermatids and formation of multinucleated giant cells. Sertoli cell-specific deletion does not affect spermatogenesis. Proteomic analysis reveals defective expression of peroxisomal and spermiogenesis-related proteins in Pex3-deleted spermatids.\",\n      \"method\": \"Conditional knockout (germ cell- and Sertoli cell-specific), fertility analysis, proteomics, fluorescence microscopy\",\n      \"journal\": \"Journal of biomedical research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — cell-type-specific conditional knockout with defined phenotypic and proteomic readout, single lab\",\n      \"pmids\": [\"38062668\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"High levels of Pex3 in S. cerevisiae induce formation of peroxisome clusters surrounded by lipid droplets, mediated by peroxisome-peroxisome and peroxisome-lipid droplet contact sites. The cytosolic domain of Pex3 binds peroxisomes directly, suggesting a role in homotypic contact site formation. This clustering is independent of Pex3 partners Pex19, Inp1, and Atg36. Lipid droplet-peroxisome contact sites require the lipid droplet-localized triacylglycerol lipase Tgl4. Overexpression of Pex3 in Drosophila similarly alters peroxisome and lipid droplet morphology.\",\n      \"method\": \"Pex3 overexpression in yeast and Drosophila, fluorescence microscopy, cytosolic domain binding assay, epistasis with pex19, inp1, atg36 deletions\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple genetic epistasis tests and direct binding assay with cross-species validation, single lab\",\n      \"pmids\": [\"40628847\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"In yeast, Pex3 binding partners Pex19, Atg30, and Inp1 compete for overlapping interaction regions on Pex3 (confirmed by crystal structure of H. polymorpha Pex3-Pex19 complex and AlphaFold2 predictions). Overexpression of any binding partner affects peroxisomal processes, with the level of overexpression being the primary determinant of competition.\",\n      \"method\": \"Crystal structure of H. polymorpha Pex3-Pex19 complex, AlphaFold2 modeling, overexpression competition assays, functional peroxisome assays\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — crystal structure plus functional competition assays, single lab\",\n      \"pmids\": [\"40847603\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Newly synthesized Pex15 (a tail-anchored peroxisomal membrane protein) is targeted to peroxisomes primarily via the Pex19- and Pex3-dependent pathway. Mistargeted Pex15 on the mitochondrial outer membrane is extracted by Msp1 and returned to peroxisomes via the Pex19-Pex3 pathway. Peroxisome-resident Pex15 is also continuously extracted by peroxisomal Msp1 and re-targeted via Pex19-Pex3.\",\n      \"method\": \"Genetic epistasis (msp1, pex19, pex3 deletions), fluorescence microscopy of Pex15 localization, functional import assays\",\n      \"journal\": \"The FEBS journal\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — epistasis with multiple deletion strains and localization studies, single lab\",\n      \"pmids\": [\"40344504\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"Depletion of PEX3 from human HeLa cells (quantitative proteomics) negatively affects 12 peroxisomal proteins and two hairpin proteins of the ER, confirming PEX19/PEX3 as the pathway for these two client classes. PEX3 deficiency also negatively affects 14 collagen-related proteins with signal peptides or N-terminal transmembrane helices.\",\n      \"method\": \"Label-free quantitative mass spectrometry of total proteome in PEX3-depleted HeLa cells and PEX3-deficient Zellweger fibroblasts, differential protein abundance analysis\",\n      \"journal\": \"International journal of molecular sciences\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — quantitative proteomics across two cellular models, single lab; functional mechanism not fully resolved for collagen clients\",\n      \"pmids\": [\"34884833\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"PEX3 is an integral peroxisomal membrane protein (N-terminus luminal, C-terminus cytoplasmic) that inserts co-translationally into the ER via the Sec61 translocon, exits in ATP-dependent budding vesicles, and serves as the membrane docking factor for the cytosolic PMP import receptor PEX19—binding it via a conserved hydrophobic groove (structurally resolved by X-ray crystallography)—to mediate class I peroxisomal membrane protein import; it also recruits pexophagy receptors (Atg36 in S. cerevisiae, Atg30 in P. pastoris) to peroxisomes and directly promotes their phosphorylation by the Hrr25 kinase to initiate selective autophagic degradation of peroxisomes, while additionally functioning in peroxisome inheritance (as a myosin V receptor), retention (via Inp1 bridging to the plasma membrane PI(4,5)P2), contact site formation with vacuoles and lipid droplets, and—in mammals—regulating plasmalogen metabolism and the AKT/GSK3β/ITGB3 signaling axis relevant to myocardial repair and spermiogenesis.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"PEX3 is an integral peroxisomal membrane protein that serves as the central membrane platform for peroxisomal membrane protein (PMP) import, peroxisome biogenesis, and the regulated turnover, inheritance, and contact-site organization of peroxisomes [#0, #1]. It adopts a single-spanning topology with an N-terminal luminal segment whose first ~33 residues are sufficient for peroxisomal targeting and a cytoplasmic C-terminal domain [#1]; this cytosolic domain folds into a novel large helical bundle that presents a membrane-distal hydrophobic groove engaging the cytosolic import receptor PEX19 with nanomolar affinity through a critical PEX19 phenylalanine (F29) [#3]. Acting as the membrane docking factor for PEX19, PEX3 is required and sufficient to dock PEX19 at organelles and to drive class I PMP import while leaving matrix and class II import intact [#0, #6], with reciprocal stabilization of the otherwise aggregation-prone PEX3 by PEX19 [#20]. PEX3 itself reaches peroxisomes through the ER: it inserts co-translationally via the SRP/Sec61 route and exits in ATP-dependent budding vesicles [#10], using redundant N-terminal sorting signals and its transmembrane segment for intra-ER routing [#9], a step dependent on PEX16 [#13]; reintroduction of PEX3 can both reassemble peroxisomes via the ER and mature pre-existing preperoxisomal vesicles [#11, #12]. Beyond biogenesis, PEX3 nucleates selective autophagic degradation of peroxisomes by recruiting and activating pexophagy receptors (Atg36 in S. cerevisiae, Atg30 in P. pastoris) and directly promoting their phosphorylation by Hrr25 kinase to initiate pexophagy [#4, #8, #18], a function balanced against PEX3 import partners that compete for overlapping surfaces on PEX3 and on the receptor [#16, #26]. PEX3 additionally controls peroxisome inheritance as a class V myosin receptor [#14], retention via Inp1 bridging to plasma-membrane PI(4,5)P2 [#19], and contact-site formation with lipid droplets [#25]. Inactivating PEX3 mutations cause Zellweger syndrome by abolishing peroxisome membrane synthesis and mislocalizing PMPs [#2], and in mammals PEX3 regulates plasmalogen metabolism that activates AKT/GSK3\\u03b2/ITGB3 signaling in myocardial repair and is required for spermiogenesis [#23, #24].\",\n  \"teleology\": [\n    {\n      \"year\": 1999,\n      \"claim\": \"Established the basic identity and topology of PEX3 as an integral peroxisomal membrane protein and its physical link to PEX19, defining the molecular entity to be studied.\",\n      \"evidence\": \"Topology mapping, GFP truncation analysis, mammalian two-hybrid, and Co-IP of in vitro translated proteins\",\n      \"pmids\": [\"10430017\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Functional role of the PEX3-PEX19 interaction not yet defined\", \"Mechanism of N-terminal targeting unresolved\"]\n    },\n    {\n      \"year\": 2000,\n      \"claim\": \"Showed PEX3 is essential for peroxisome membrane synthesis and that its trafficking is independent of classical COPI/COPII secretory routes, while linking PEX3 loss to human disease.\",\n      \"evidence\": \"Brefeldin A, dominant-negative SAR1, and microscopy in Zellweger patient cells\",\n      \"pmids\": [\"10871277\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Actual trafficking route of PEX3 left unspecified\", \"Which PMPs are mislocalized and why was not fully resolved\"]\n    },\n    {\n      \"year\": 2003,\n      \"claim\": \"Localized the PEX3-PEX19 interaction in living cells to the peroxisome and mapped targeting versus binding domains, distinguishing PEX3's two functional modules.\",\n      \"evidence\": \"Live-cell FRET imaging and domain-deletion rescue in patient fibroblasts\",\n      \"pmids\": [\"12924628\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of binding not yet known\", \"Dynamics of the docking cycle unresolved\"]\n    },\n    {\n      \"year\": 2004,\n      \"claim\": \"Defined PEX3 as the membrane docking factor that is necessary and sufficient to recruit PEX19 and to drive class I but not class II PMP import, establishing pathway selectivity.\",\n      \"evidence\": \"Co-IP, heterologous organelle docking, dominant-negative inhibition, class I/II import assays\",\n      \"pmids\": [\"15007061\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular interface not defined at residue level\", \"How docking converts to membrane insertion unclear\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Provided the atomic-resolution mechanism of PEX19 recognition, revealing a novel helical bundle fold and a hydrophobic groove engaging PEX19 F29 with nanomolar affinity.\",\n      \"evidence\": \"X-ray crystallography of the PEX3 cytosolic domain with PEX19 peptide plus binding and mutagenesis\",\n      \"pmids\": [\"20554521\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Crystallized only a PEX19-derived peptide, not full-length PEX19\", \"Membrane-embedded context not captured\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Functionally validated the crystallographically identified groove as required for PMP insertion and preperoxisome maturation, and discovered PEX3's role in recruiting the pexophagy receptor.\",\n      \"evidence\": \"Mutagenesis of groove residues with biogenesis assays; pexophagy-specific pex3 alleles and Atg36 mislocalization in yeast\",\n      \"pmids\": [\"22624858\", \"22643220\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How a single groove serves both PEX19 docking and Atg36 recruitment unclear\", \"Mechanism of Atg36 activation not yet defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Resolved how PEX3 reaches peroxisomes via the ER, identifying redundant N-terminal sorting signals and a transmembrane-dependent exit step conserved across species.\",\n      \"evidence\": \"Pex3/Sec66 chimeras and domain swaps in yeast and Drosophila cells\",\n      \"pmids\": [\"23951409\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Identity of the ER subdomain machinery unresolved\", \"Vesicle budding factors not identified\"]\n    },\n    {\n      \"year\": 2014,\n      \"claim\": \"Refined the biogenesis model by showing preperoxisomal vesicles can form without PEX3 and that PEX3 sorts to and matures them, while PEX16 mediates ER-to-peroxisome PEX3 transport; also defined a mammalian pexophagy pathway and a myosin V receptor role.\",\n      \"evidence\": \"Microscopy/fractionation with pex3 atg1 double deletions; ssPEX3 time-lapse imaging with PEX16 perturbation; PEX3 overexpression with NBR1/p62 knockdown; myosin globular-tail binding in Y. lipolytica\",\n      \"pmids\": [\"24590171\", \"25002403\", \"25007327\", \"19822674\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"De novo versus preexisting-vesicle origin of peroxisomes still debated across systems\", \"Ubiquitinated peroxisomal target in PEX3-driven pexophagy unidentified\", \"Whether mammalian PEX3 acts as a myosin receptor untested\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Defined the early secretory entry of PEX3 (SRP/Sec61 co-translational insertion, ATP-dependent ER exit) and showed PEX3 actively initiates pexophagy by promoting receptor phosphorylation rather than mere docking.\",\n      \"evidence\": \"Photocrosslinking and fluorescence spectroscopy of nascent chains plus ER exit assay; binding/phosphorylation/Atg11 recruitment assays in P. pastoris\",\n      \"pmids\": [\"26572236\", \"25694426\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Budding vesicle coat machinery unidentified\", \"Kinase responsible for Atg30 phosphorylation not yet pinned in this study\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Revealed competitive regulation of pexophagy through overlapping binding of Pex3 and Atg37 on Atg30, showing Pex3 negatively and Atg37 positively tune Hrr25 phosphorylation; also implicated Pex3 in peroxisome-vacuole contact sites.\",\n      \"evidence\": \"Binding competition and phosphorylation assays in P. pastoris; EM/fluorescence with Pex3 overexpression in H. polymorpha\",\n      \"pmids\": [\"29260977\", \"30595161\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Contact-site role rests on overexpression microscopy without mechanistic dissection\", \"How competing inputs are integrated to set pexophagy threshold unclear\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Extended PEX3's PEX19-docking function to a divergent eukaryote, establishing Pex3 as essential master regulator of glycosome biogenesis in trypanosomes.\",\n      \"evidence\": \"RNAi depletion, fractionation, microscopy, and Co-IP in trypanosomes (two independent studies)\",\n      \"pmids\": [\"31341002\", \"31369765\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Structural basis of the divergent trypanosomal interface not solved\", \"Therapeutic exploitation untested\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Reconstituted the catalytic role of Pex3 in pexophagy and resolved the molecular basis of peroxisome retention, showing Pex3 directly drives Hrr25 phosphorylation of Atg36 and bridges Inp1 to plasma-membrane PI(4,5)P2.\",\n      \"evidence\": \"In vitro phosphorylation with recombinant Pex3/Hrr25/Atg36 plus Co-IP and genetics; artificial PM-PER tether rescue with PI(4,5)P2 binding assays\",\n      \"pmids\": [\"32958557\", \"32970792\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"How Pex3 allosterically enhances the Atg36-Hrr25 reaction unresolved\", \"Whether mammalian PEX3 uses an analogous retention tether unknown\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Mapped the human PEX3-dependent clientele by proteomics, confirming peroxisomal and ER-hairpin clients and unexpectedly linking PEX3 deficiency to collagen-related proteins.\",\n      \"evidence\": \"Label-free quantitative proteomics in PEX3-depleted HeLa cells and Zellweger fibroblasts\",\n      \"pmids\": [\"34884833\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism connecting PEX3 to collagen-pathway clients unresolved\", \"Direct versus indirect dependence not distinguished\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Linked PEX3 to organ-level physiology, showing it shapes plasmalogen metabolism that activates AKT/GSK3\\u03b2/ITGB3 signaling for myocardial regeneration and is required for spermiogenesis.\",\n      \"evidence\": \"Cardiomyocyte-specific and germ cell-specific Pex3 knockout mice with lipidomics, proteomics, and pathway analysis\",\n      \"pmids\": [\"38951640\", \"38062668\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How plasmalogen changes mechanistically license ITGB3 membrane localization unclear\", \"Whether spermatid defects are plasmalogen-dependent untested\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Integrated PEX3 into a competitive partner network and contact-site biology, showing Pex19/Atg30/Inp1 compete for overlapping Pex3 surfaces, that Pex3 drives peroxisome-lipid droplet contacts, and that it cooperates in Msp1-mediated re-targeting of tail-anchored Pex15.\",\n      \"evidence\": \"H. polymorpha Pex3-Pex19 crystal structure with AlphaFold2 and overexpression competition; cross-species clustering assays; msp1/pex19/pex3 epistasis for Pex15\",\n      \"pmids\": [\"40847603\", \"40628847\", \"40344504\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"How partner competition is regulated physiologically rather than by overexpression unclear\", \"Contact-site clustering function characterized largely by overexpression\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How a single PEX3 hydrophobic groove temporally coordinates competing biogenesis, inheritance, retention, and pexophagy partners, and how mammalian PEX3 lipid/signaling roles connect to its conserved membrane-import function, remain unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No unified model for spatiotemporal switching between PEX3 partners\", \"Mammalian retention/inheritance and pexophagy roles largely inferred from yeast\", \"Mechanistic link between PEX3 import function and plasmalogen/AKT signaling unestablished\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [0, 6, 3]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [18, 8, 16]},\n      {\"term_id\": \"GO:0008289\", \"supporting_discovery_ids\": [15]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005777\", \"supporting_discovery_ids\": [1, 0, 2]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [10, 9, 13]},\n      {\"term_id\": \"GO:0005635\", \"supporting_discovery_ids\": [11]},\n      {\"term_id\": \"GO:0005811\", \"supporting_discovery_ids\": [25]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1852241\", \"supporting_discovery_ids\": [0, 2, 12]},\n      {\"term_id\": \"R-HSA-9612973\", \"supporting_discovery_ids\": [4, 18, 7]},\n      {\"term_id\": \"R-HSA-9609507\", \"supporting_discovery_ids\": [0, 10, 27]},\n      {\"term_id\": \"R-HSA-1643685\", \"supporting_discovery_ids\": [2]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"PEX19\", \"PEX16\", \"Atg36\", \"Atg30\", \"Hrr25\", \"Inp1\", \"Atg37\", \"Pex15\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":7,"faith_total":7,"faith_pct":100.0}}