Affinage

PEX5

Peroxisomal targeting signal 1 receptor · UniProt P50542

Length
639 aa
Mass
70.9 kDa
Annotated
2026-06-10
94 papers in source corpus 38 papers cited in narrative 37 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 9/9 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

PEX5 is the cycling import receptor that delivers folded peroxisomal matrix proteins from the cytosol into the peroxisomal lumen (PMID:9418886, PMID:19632994). It recognizes PTS1-bearing cargo through its C-terminal TPR domain, where two clusters of three TPRs encircle the PTS1 pentapeptide and the receptor binding cavity compacts upon ligand engagement to enforce selectivity (PMID:11101887, PMID:25369882). Cargo recognition is a comparatively simple, high-affinity event (Kd ~35 nM) not modulated by Hsp70 or the PEX12 RING domain (PMID:12456682). The elongated N-terminal half carries seven di-aromatic WxxxF/Y pentapeptide motifs, each binding the three-helical N-terminal domain of the docking peroxin PEX14 with nanomolar affinity, plus a distinct lower-affinity LVxEF site whose fast dissociation kinetics are themselves required for receptor processing (PMID:10026185, PMID:11438541, PMID:19197237, PMID:24235149). The longer isoform PEX5L additionally recruits PEX7 through a conserved 21-residue motif to co-import PTS2 cargo, a function genetically separable from PTS1 import (PMID:11546814, PMID:10767287); defects in this PEX5L–PEX7 interaction cause rhizomelic chondrodysplasia punctata type 5 and congenital cataracts (PMID:26220973, PMID:33389129). Rather than acting only at the membrane, PEX5 enters the lumen of the import translocon (DTM), releases cargo with the participation of the PEX14 N-terminal domain, and is then retrieved (PMID:21976670, PMID:35931083, PMID:28765278). Recycling is initiated by monoubiquitination of a conserved N-terminal cysteine (Cys11) as a reversible thioester conjugate; this modification is mandatory for the ATP-dependent extraction of PEX5 from the membrane by the PEX1–PEX6 AAA-ATPase, which threads and globally unfolds the receptor together with its unfolded ubiquitin tag (PMID:23963456, PMID:29884772, PMID:36442669, PMID:38470934). The cysteine acceptor is itself a redox switch coupling glutathione oxidation to import competence, and USP9X is the principal cytosolic deubiquitinase that regenerates free PEX5 (PMID:22371489, PMID:24118911, PMID:28760655). Beyond matrix import, PEX5 stabilizes PEX14, escorts adipose triglyceride lipase to peroxisome–lipid droplet contacts to drive fasting-induced lipolysis, and—when its export is blocked—accumulates as ubiquitinated PEX5 to trigger pexophagy as an organelle quality-control mechanism (PMID:23009329, PMID:31996685, PMID:26086376).

Mechanistic history

Synthesis pass · year-by-year structured walk · 20 steps
  1. 1998 High

    Established PEX5 as the genetic determinant of peroxisomal matrix import and revealed isoform-specific division of labor between PTS1 and PTS2 cargo.

    Evidence CHO mutant complementation and TPR missense mutations in PEX5-defective cells

    PMID:9418886

    Open questions at the time
    • Molecular basis of PTS1 recognition not yet structurally defined
    • Mechanism by which the long isoform mediates PTS2 import unknown
  2. 1999 High

    Defined PEX5 architecture as bifunctional — an N-terminal half bearing reiterated PEX14-binding motifs and a C-terminal cargo-binding half — and quantified the nanomolar PEX5–PEX14 docking interaction.

    Evidence SPR, sizing chromatography, EM, and in vitro reconstitution of recombinant PEX5 and PEX14

    PMID:10026185

    Open questions at the time
    • Number and individual contributions of the PEX14 sites not resolved
    • Oligomeric state in vivo uncertain
  3. 2000 High

    Solved the structural basis of PTS1 recognition, showing two TPR clusters surround the peptide via a hinge-enabled single binding site.

    Evidence X-ray crystallography of the PEX5 TPR domain with a PTS1 pentapeptide

    PMID:11101887

    Open questions at the time
    • Conformational dynamics of cargo loading/release not addressed
    • Full-length receptor architecture not captured
  4. 2001 High

    Defined the molecular grammar of receptor docking and the PEX5L-specific PEX7 recruitment motif that underlies PTS2 import.

    Evidence Two-hybrid, SPR, mutational analysis of WxxxF/Y motifs; domain mapping of the PEX5L 21-aa PEX7-binding motif

    PMID:11438541 PMID:11546814

    Open questions at the time
    • Why seven redundant PEX14 sites are needed unresolved
    • Functional difference between sites not yet defined
  5. 2005 High

    Separated import (ATP-independent) from export (ATP-dependent), assigning PEX1/PEX6/PEX26 to receptor retrieval and showing PEX5 transits between membrane subcomplexes.

    Evidence Cell-free translocation/export assays with isolated peroxisomes, blue-native PAGE, peroxin-defective cells

    PMID:16314507

    Open questions at the time
    • Molecular trigger linking docking to export not defined
    • Composition of the 500/800 kDa complexes incomplete
  6. 2009 High

    Ordered the import cycle by placing cargo translocation across the membrane upstream of the first cytosolic ATP-dependent step, and provided solution architecture of the docking complex.

    Evidence Cargo-centered cell-free import system with ATP depletion and protease protection; SAXS of Pex5–Pex14–PTS1 complexes

    PMID:19584060 PMID:19632994

    Open questions at the time
    • Mechanism of translocation across the bilayer unknown
    • Stoichiometry interpretation limited by SAXS resolution
  7. 2009 High

    Defined the PEX14 N-terminal fold and showed PEX5 and PEX19 compete for the same surface, integrating receptor docking with membrane-protein biogenesis.

    Evidence NMR structure with competitive binding and in vivo localization

    PMID:19197237

    Open questions at the time
    • Functional consequence of PEX5/PEX19 competition in vivo not fully dissected
  8. 2012 High

    Identified Cys11 monoubiquitination as a thioester conjugate and USP9X as the cytosolic deubiquitinase regenerating free PEX5.

    Evidence Biochemical fractionation, in vitro DUB assays, mass spectrometry in rat liver and HeLa

    PMID:22371489

    Open questions at the time
    • E3 ligase responsible for Cys11 conjugation not identified here
    • Regulation of USP9X activity unknown
  9. 2013 High

    Demonstrated that Cys11 monoubiquitination is mandatory for ATP-dependent extraction and that Cys11 acts as a redox switch coupling oxidative state to import competence, with selective effects on catalase.

    Evidence Cell-free import/export with PEGylation; C11K mutagenesis and redox manipulation in fibroblasts

    PMID:23963456 PMID:24118911 PMID:28760655

    Open questions at the time
    • How redox state is sensed in vivo not fully resolved
    • Physiological oxidant relevant to the switch undefined
  10. 2013 High

    Mechanistically linked PEX5 to cargo release and to a non-WxxxF/Y processing site, and to PEX14 stabilization.

    Evidence In vitro catalase tetramerization assays; NMR/SPR of the LVxEF site; CHO mutant complementation for PEX14 stability

    PMID:21976670 PMID:23009329 PMID:24235149

    Open questions at the time
    • Catalase work is single-lab in vitro
    • PEX14-stabilization findings Medium-confidence and single-lab
  11. 2014 High

    Showed ligand-induced compaction of the TPR cavity and that cargo steric features tune import efficiency.

    Evidence X-ray crystallography of PEX5–cargo complexes with in-cell import efficiency assays

    PMID:25369882

    Open questions at the time
    • Generality of compaction across diverse cargoes untested
    • Single-lab
  12. 2015 High

    Connected receptor recycling failure to organelle quality control, showing stalled monoubiquitinated PEX5 triggers pexophagy.

    Evidence Fluorescence microscopy, autophagy inhibitors, C11A mutants in mammalian cells

    PMID:26086376

    Open questions at the time
    • Autophagy receptor recognizing stalled Ub-PEX5 not identified
    • Single-lab
  13. 2017 High

    Characterized the import translocon as a large cavity (DTM) into which PEX5 enters, and identified TRIM37-mediated K464 monoubiquitination as a PEX5-stabilizing modification distinct from Cys11.

    Evidence Truncated PEX5 DTM probes with proteinase K/alkaline extraction; Co-IP, in vitro ubiquitylation, RNAi, import assays

    PMID:28724525 PMID:28765278

    Open questions at the time
    • DTM mechanistic conclusions partly inferential
    • Interplay between TRIM37 K464 and Cys11 ubiquitination unresolved
  14. 2018 High

    Established DTM-embedded Ub-PEX5 as a direct PEX1–PEX6 substrate that is globally unfolded during extraction, and defined the interaction map of chemically defined monoubiquitinated PEX5 with docking and export machinery.

    Evidence Cell-free system with photoaffinity cross-linking/PEGylation; click-chemistry monoubiquitinated PEX5 pull-downs and complementation

    PMID:29884772 PMID:30375424

    Open questions at the time
    • Force-generation and threading directionality mechanistically incomplete
    • Single-lab reconstitutions
  15. 2020 High

    Extended PEX5 function beyond matrix import to fasting-induced lipolysis by escorting ATGL to peroxisome–lipid droplet contacts in vivo.

    Evidence Co-IP, live imaging, adipocyte-specific PEX5-knockout mice with lipolysis assays

    PMID:31996685

    Open questions at the time
    • Whether this uses the canonical TPR cargo pathway unclear
    • Molecular basis of ATGL recognition undefined
  16. 2021 High

    Linked PEX5L-specific PTS2 import defects to human disease and dissected step-specific mutations that uncouple PTS1 from PTS2 import.

    Evidence Patient mutation analysis (c.722dupA; F218S), import assays, Co-IP, complementation in fibroblasts

    PMID:26220973 PMID:33389129

    Open questions at the time
    • Tissue-specific consequences of PTS2 loss not mechanistically explained
  17. 2022 High

    Resolved the complete lumenal import-and-recycling itinerary and the ubiquitin-unfolding requirement that initiates threading-based extraction.

    Evidence Xenopus egg extract import system; cell-free extraction with engineered/cross-linked ubiquitin and chimeric PEX5

    PMID:35931083 PMID:36442669

    Open questions at the time
    • Identity of the lumenal docking/ligase contacts incompletely mapped
    • How multiple chains are threaded simultaneously unresolved
  18. 2023 Medium

    Placed PEX13 as a regulator preventing pexophagy of healthy peroxisomes by limiting accumulation of ubiquitinated PEX5.

    Evidence CRISPR KO, quantitative microscopy, zebrafish, autophagy assays

    PMID:36541703

    Open questions at the time
    • Single-lab
    • Direct link between PEX13 levels and Ub-PEX5 turnover correlative
  19. 2024 High

    Explained why cysteine, not lysine, is the ubiquitin acceptor: reversible thioester ubiquitination prevents polyubiquitination and proteasomal targeting, enabling efficient recycling.

    Evidence Rat liver cell-free system, C11K mutagenesis, ubiquitin chain and extraction analysis

    PMID:38470934

    Open questions at the time
    • In vivo balance of E2-mediated deubiquitination versus chain extension not quantified
  20. 2025 Medium

    Provided structural basis for the Pex5–Pex8 interaction in yeast that couples cargo translocation to recruitment of the Pex2/Pex10/Pex12 ligase, and revealed non-canonical cargo interaction surfaces.

    Evidence Cryo-EM of Pex5–Pex8 (preprint) and Pex5–Eci1 complexes with functional import assays in yeast

    PMID:40376748 PMID:bio_10.1101_2025.08.30.673231

    Open questions at the time
    • One source is a preprint
    • Whether the Pex8-dependent step generalizes to mammals (which lack a clear Pex8) unknown

Open questions

Synthesis pass · forward-looking unresolved questions
  • The physical nature of the translocation pore and how the receptor and cargo cross the bilayer remain incompletely defined.
  • Whether PEX5L itself forms the physiological translocon pore is not established in vivo
  • The complete subunit composition and gating of the DTM channel are unknown
  • How cargo of varying size and fold is accommodated remains undefined

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0038024 cargo receptor activity 4 GO:0060090 molecular adaptor activity 3 GO:0005198 structural molecule activity 1 GO:0140299 molecular sensor activity 1
Localization
GO:0005777 peroxisome 3 GO:0005829 cytosol 3 GO:0005811 lipid droplet 1
Pathway
R-HSA-392499 Metabolism of proteins 4 R-HSA-9609507 Protein localization 4 R-HSA-1643685 Disease 2 R-HSA-9612973 Autophagy 2 R-HSA-1430728 Metabolism 1
Partners
PEX1PEX12PEX13PEX14PEX6PEX7TRIM37USP9X
Complex memberships
DTM (peroxisomal matrix protein translocon)PEX1-PEX6 AAA-ATPase complex (substrate)PEX5L-PEX7 receptor complex

Evidence

Reading pass · 37 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2000 Crystal structure of human PEX5 C-terminal fragment containing all seven TPR motifs in complex with a PTS1 pentapeptide revealed that two clusters of three TPRs almost completely surround the peptide, while a hinge region (TPR4) forms a distinct structure enabling the two sets of TPRs to form a single binding site, establishing the molecular basis for PTS1 recognition via a novel TPR-peptide interaction mode. X-ray crystallography (crystal structure of PEX5 TPR domain in complex with PTS1 peptide) Nature structural biology High 11101887
1999 Recombinant human PEX5 forms homotetramers (both PEX5L and PEX5S isoforms) and binds the N-terminal fragment of PEX14 (residues 1-78) with very high affinity in the low nanomolar range. Stable in vitro complexes revealed that PEX5 possesses multiple PEX14-binding sites distributed throughout its N-terminal half, while the C-terminal TPR half binds PTS1 proteins. A pentapeptide motif reiterated seven times in PEX5 was identified as determinant for PEX14 interaction. Surface plasmon resonance, sizing chromatography, electron microscopy, in vitro binding assays The Journal of biological chemistry High 10026185
1998 PEX5 (PTS1R) is required for import of both PTS1 proteins and PTS2 proteins in CHO cells; the longer isoform PTS1RL is specifically required for PTS2 import, while both isoforms mediate PTS1 import. Missense mutations in TPR1 (G298E) and TPR6 (G485E) of PTS1RS abolished PTS1 import, demonstrating functional importance of TPR domains in protein translocation. CHO cell mutant complementation, reverse transcription-PCR mutation analysis, import assays in PEX5-defective cell lines Molecular and cellular biology High 9418886
2001 The seven di-aromatic pentapeptide repeat motifs (WX(E/D/Q/A/S)(E/D/Q)(F/Y)) in the N-terminal half of human PEX5 each independently bind the same site in the N-terminus of PEX14 with nanomolar affinity. Mutational analysis showed conserved aromatic amino acids at positions 1 and 5 of each motif are essential for high-affinity PEX14 binding, likely forming hydrophobic anchors in an amphipathic alpha-helix. Two-hybrid analysis in mammalian cells, in vitro binding assays, mutational analysis, surface plasmon resonance The Journal of biological chemistry High 11438541
2001 Human PEX5L (but not PEX5S) physically interacts with PEX7 and is required for PTS2 protein import in mammalian cells. The region amino acids 191-222 of PEX5L is sufficient for PEX7 interaction and amino acids 1-214 are sufficient for peroxisome targeting. A conserved 21-amino-acid motif (aa 209-229) shared with yeast Pex18p/Pex21p is required for both PEX7 interaction and PTS2 import; a serine mutation in this motif abolishes PTS2 import and reduces PEX5L-PEX7 interaction in vitro. Domain mapping, in vitro binding, complementation in mammalian cells, mutagenesis The Journal of biological chemistry High 11546814
1999 PEX12 zinc-binding domain interacts with PEX5 and PEX10; a patient missense mutation S320F in PEX12 reduces binding to both PEX5 and PEX10. Overexpression of PEX5 or PEX10 suppresses this PEX12 mutation. PEX12 and PEX10 act downstream of PEX5 docking at the peroxisome surface, not in the docking step itself. Two-hybrid studies, blot overlay assays, co-immunoprecipitation, genetic suppression by overexpression The Journal of cell biology High 10562279
2000 Disruption of the Pex5pL-Pex7p interaction by the S214F missense mutation (adjacent to the PEX5L-specific 37-amino acid insertion) completely abolishes PTS2 protein import in mammals while leaving PTS1 import intact, demonstrating that the Pex5pL-Pex7p interaction is essential specifically for PTS2 import. CHO cell mutant isolation, complementation with mutant Pex5p constructs, co-immunoprecipitation, import assays The Journal of biological chemistry High 10767287
2005 PEX5 import into peroxisomes is ATP-independent, whereas its export back to the cytosol requires ATP. PEX1 and PEX6 (AAA ATPases) and their recruiter PEX26 are essential for PEX5 export. PEX14 is required for PEX5 docking/import. DTM-embedded PEX5 exists in two distinct complexes of ~500 kDa and ~800 kDa comprising different peroxins (including PEX14 and PEX2), indicating PEX5 transits between subcomplexes during its cycle. Cell-free translocation system, radiolabeled PEX5 import/export assays with isolated peroxisomes, blue-native PAGE, PEX-defective cell lines Molecular and cellular biology High 16314507
2009 The N-terminal domain of PEX14 adopts a three-helical fold and binds both PEX5 (via its WxxxF/Y motif) and PEX19 competitively at the same surface but with opposite directionality. Mutations of PEX14 residues in the PEX5/PEX19 binding region disrupt binding in vitro and impair peroxisomal membrane localization of PEX14 in vivo. NMR structure determination, competitive binding assays, mutagenesis, in vivo localization The EMBO journal High 19197237
2012 PEX5 is monoubiquitinated at a conserved cysteine residue (Cys11 in human) forming a thioester conjugate (Ub-PEX5). USP9X is the primary deubiquitinase acting on Ub-PEX5 in rat liver and HeLa cells, identified by biochemical fractionation; USP9X is an elongated monomeric protein capable of hydrolyzing thioester, isopeptide, and peptide bonds. Biochemical fractionation, in vitro deubiquitinase assays, identification by mass spectrometry The Journal of biological chemistry High 22371489
2013 PEX5 binds monomeric catalase (not tetrameric catalase) through domains in both its N- and C-terminal halves, potently inhibiting catalase tetramerization. The PEX5-catalase interaction is disrupted by the N-terminal domain of PEX14, with one or two of the seven PEX14-binding diaromatic motifs in PEX5 involved, indicating PEX14 participates in cargo release. In vitro binding assays, native gel electrophoresis, interaction disruption assays with PEX14 N-terminal domain The Journal of biological chemistry High 21976670
2013 PEX5 is monoubiquitinated at a conserved cysteine residue (Cys11); this modification is mandatory for ATP-dependent extraction of PEX5 from the peroxisomal membrane back to the cytosol. Cargo protein translocation across the peroxisomal membrane occurs upstream of PEX5 ubiquitination (i.e., prior to the first ATP-dependent step). In vitro import/export system with rat liver peroxisomes, PEGylation assays to monitor cysteine modification, protease protection assays The Journal of biological chemistry High 23963456
2013 Cys11 of human PEX5 functions as a redox switch: exposure to oxidized glutathione yields a ubiquitination-deficient PEX5, impairing PTS1 import. Substitution of Cys11 by lysine counteracts this effect. Oxidative stress selectively inhibits import of catalase (non-canonical PTS1) more than canonical PTS1 reporters. PEX5 does not oligomerize in cellulo, and oxidative stress does not affect PEX5-substrate binding per se. PEGylation assays, site-directed mutagenesis (C11K), live-cell import assays in human fibroblasts, redox manipulation Traffic (Copenhagen, Denmark) High 24118911 28760655
2017 TRIM37 localizes to peroxisomal membranes and ubiquitylates PEX5 at K464 via interaction with the C-terminal 51 amino acids (CT51) of PEX5; this monoubiquitination stabilizes PEX5 by preventing its proteasomal degradation. TRIM37 depletion or K464A/ΔCT51 PEX5 mutations reduce PEX5 abundance and impair PTS protein import. Co-immunoprecipitation, ubiquitylation assays, site-directed mutagenesis, RNAi knockdown, import assays in human cells The Journal of cell biology High 28724525
2013 In Pichia pastoris, Pex5 functions as a dimer/oligomer whose homo- and hetero-oligomeric interactions (with Pex8 via its N-terminal domain, aa 1-110) regulate cargo binding and release. Cysteine 10 of Pex5 forms redox-sensitive disulfide-linked oligomers with highest PTS1 cargo affinity; DTT reduction causes transition to noncovalent dimer and partial cargo release. Interaction of Pex5 N-terminal domain with a conserved C-terminal motif of Pex8 further facilitates cargo release under reducing conditions. In vitro binding assays, disulfide crosslinking, dithiothreitol reduction, mutagenesis (C10), import assays The Journal of biological chemistry Medium 23902771
2013 A novel PEX5-PEX14 interaction site in PEX5 was identified with the sequence LVAEF (consensus LVXEF). NMR structure of Pex5-(57-71) with PEX14 N-terminal domain showed this motif binds in an alpha-helical orientation similar to WxxxF/Y motifs but with leucine occupying the tryptophan pocket. SPR showed 33-fold faster dissociation than WxxxF/Y motifs; substituting this site with a higher-affinity WxxxF/Y motif impaired protein import, indicating distinct kinetics of this novel site are required for receptor processing. Peptide library screening, ligand blot analysis, NMR structure determination, SPR, in vivo import assays with alanine substitution mutants The Journal of biological chemistry High 24235149
2018 DTM-embedded monoubiquitinated PEX5 (Ub-PEX5) directly interacts with both PEX1 and PEX6 through its ubiquitin moiety, and the PEX5 polypeptide chain is globally unfolded during the ATP-dependent extraction event, establishing that DTM-embedded Ub-PEX5 is a bona fide substrate of the PEX1-PEX6 AAA ATPase complex. Cell-free in vitro system, photoaffinity cross-linking, protein PEGylation assays The Journal of biological chemistry High 29884772
2022 PEX5 accompanies cargo completely into the peroxisomal lumen (not just to the membrane). WxxxF/Y motifs near PEX5's N-terminus bind a lumenal domain of the docking complex inside the peroxisome. An amphipathic helix in PEX5 initiates recycling by binding the lumenal side of the ubiquitin ligase. The N-terminus of PEX5 then emerges in the cytosol for monoubiquitination, and finally PEX5 is extracted from the lumen with unfolding of the receptor and cargo release. Xenopus egg extract import system, domain deletion/mutation analysis, protease protection and biochemical assays Molecular cell High 35931083
2017 The peroxisomal matrix protein translocon (DTM) is a large cavity-forming protein assembly into which cytosolic PEX5 enters to release its cargo. Truncated PEX5 molecules up to residue 197 can be accommodated in excess. PEX5-PEX14 interaction within the DTM is stable at pH 11.5, indicating DTM-bound PEX5 resistance to alkaline extraction does not reflect direct lipid bilayer contact. Truncated PEX5 molecules as DTM probes, proteinase K accessibility assays, alkaline extraction assays, in vitro binding The Journal of biological chemistry Medium 28765278
2015 PEX5 proteins fused to bulky C-terminal tags trigger peroxisome degradation by autophagy in mammalian cells. This requires monoubiquitination of the N-terminal cysteine of PEX5 (Cys11), which marks PEX5 for recycling. The C-terminal tag does not inhibit monoubiquitination but blocks PEX5 export from the peroxisomal membrane, indicating that prolonged membrane-association of monoubiquitinated PEX5 triggers pexophagy as a quality control mechanism. Fluorescence microscopy, autophagy inhibitors, mutant PEX5 constructs (C11A abolishes monoubiquitination), quantitative pexophagy assays Autophagy High 26086376
2011 AWP1/ZFAND6 stimulates PEX5 export from peroxisomes. AWP1 interacts with PEX6 AAA ATPase (but not Pex1-Pex6 complexes) and preferentially binds cysteine-ubiquitinated PEX5 over unmodified PEX5 via its A20 zinc-finger domain. AWP1 knockdown reduces PTS1 protein import and destabilizes PEX5, similarly to defects in PEX1/PEX6/PEX26. Biochemical fractionation, in vitro Pex5 export assay, recombinant protein stimulation assay, antibody inhibition, RNAi knockdown, co-immunoprecipitation Traffic (Copenhagen, Denmark) High 21980954
2014 High-resolution structural analysis revealed that PEX5 adapts its conformation during PTS1 cargo recognition: the receptor binding cavity shrinks to one-third of its original volume upon ligand binding (ligand-induced compaction). A single-residue mutation in cargo protein alanine-glyoxylate aminotransferase that removes steric occlusion increases peroxisomal import efficiency from 34% to 80%. X-ray crystallography of PEX5-cargo complexes, import efficiency assays in cells Traffic (Copenhagen, Denmark) High 25369882
2022 The PEX5-linked monoubiquitin is unfolded at a pre-extraction stage and serves as the extraction initiator; the complete ubiquitin-PEX5 conjugate is threaded by PEX1•PEX6. Chimeric PEX5 molecules with branched C-terminal polypeptide structures can still be extracted, suggesting simultaneous threading of more than one polypeptide chain. Intra-molecularly cross-linked ubiquitin conjugated to residue 11 of PEX5 blocks extraction, confirming ubiquitin unfolding is required. Cell-free in vitro extraction system, engineered PEX5 and ubiquitin molecules, cross-linked ubiquitin, PEGylation assays Journal of molecular biology High 36442669
2024 PEX5 ubiquitinated at cysteine 11 (thioester bond) cannot retain a polyubiquitin chain because cysteine-linked ubiquitination is reversible, with E2-mediated deubiquitination being faster than polyubiquitination. A Lys11 PEX5 variant is polyubiquitinated at the peroxisomal membrane, impairing extraction. Thus, cysteine as the ubiquitin acceptor prevents polyubiquitination and proteasomal targeting while enabling reversible monoubiquitination for efficient recycling. Rat liver cell-free in vitro system, site-directed mutagenesis (C11K), ubiquitin chain analysis, extraction assays PLoS biology High 38470934
2018 Chemically synthesized monoubiquitinated PEX5 (via click chemistry) binds PEX7/PTS2 complex and can restore PTS2 protein import in ΔPEX5 fibroblasts in vivo. In vitro pull-downs showed monoubiquitinated PEX5 interacts with PEX13, PEX14 (independent of ubiquitination status) and with REM components PEX1, PEX6, and PEX26 (interactions enhanced by ubiquitination). Chemical ubiquitin conjugation (click chemistry), in vitro pull-down assays, complementation in ΔPEX5 fibroblasts Scientific reports High 30375424
2013 Absence of PEX5 in CHO cells (ZPEG101 mutant) results in unstable PEX14 due to its inefficient translocation to the peroxisomal membrane, establishing that PEX5 stabilizes PEX14 in addition to its import receptor role. The fifth WXXXF/Y pentapeptide motif in PEX5L is an auxiliary PEX14-binding site required for PEX14 stability. PEX5-PEX13 interaction is essential for PTS1 and catalase import but not PTS2 import. PEX5-deficient CHO cell mutant (ZPEG101), complementation with Pex5p mutants, western blotting for PEX14 stability, import assays The Biochemical journal Medium 23009329
2020 PEX5 mediates fasting-induced lipolysis by escorting adipose triglyceride lipase (ATGL) to contact points between peroxisomes and lipid droplets. During fasting, peroxisomes move toward lipid droplets in a KIFC3-dependent manner, increasing peroxisome-lipid droplet contacts, and PEX5 facilitates ATGL translocation onto lipid droplets. In adipocyte-specific PEX5-knockout mice, ATGL recruitment to lipid droplets was defective and fasting-induced lipolysis was attenuated. Co-immunoprecipitation, fluorescence microscopy, adipocyte-specific conditional knockout mice, lipolysis assays Nature communications High 31996685
2009 Cargo protein translocation across the peroxisomal membrane (including release into the matrix) occurs prior to PEX5 ubiquitination in a cargo-protein-centered in vitro import system, mapping translocation downstream of reversible docking and upstream of the first cytosolic ATP-dependent step. Cargo-protein-centered in vitro peroxisomal import system, ATP depletion experiments, protease protection assays The Journal of biological chemistry High 19632994
2021 Loss of the PEX5 long isoform (PEX5L) alone causes selective deficiency in PTS2 protein import (not PTS1 import), resulting in rhizomelic chondrodysplasia punctata type 5 (RCDP5) in humans. A frameshift mutation c.722dupA in PEX5L-specific exon 9 abolishes PEX5L expression; reintroduction of PEX5L restores PTS2 import in patient fibroblasts. Patient mutation analysis, isoform-specific expression studies, PTS1/PTS2 import assays in fibroblasts, complementation with PEX5L Human molecular genetics High 26220973
2021 PEX5 mutation F218S (missense) allows normal PTS1 import, normal entry into the DTM, normal monoubiquitination and export, but fails to form a stable trimeric complex with PEX7 and a PTS2 cargo protein, thus failing to promote PTS2 protein import, causing congenital cataracts. In vitro import assays, co-immunoprecipitation, site-directed mutagenesis, patient fibroblast functional studies Human genetics High 33389129
2022 Full-length human PEX5L is monomeric in solution with a compact conformation, spontaneously binds to lipid bilayers (accumulating ~100-fold), and forms ion-conducting membrane channels in artificial horizontal bilayers. The C-terminal cargo-binding domain (residues 336–639) is required for pore formation; truncated PEX5L(1-335) binds membranes but does not form channels, suggesting PEX5L is the pore-forming component of the peroxisomal translocon. Fluorescence TCSPC (diffusion measurement), electrophysiological single-channel recording in horizontal lipid bilayers, site-specific fluorescent labeling Biological chemistry Medium 36260915
2021 PEX5 NTD harbors multiple membrane interaction sites involving amphipathic alpha-helical regions that include WxxxF/Y motifs; these helical regions are stabilized in the presence of membrane-mimicking bicelles (NMR). PEX14 NTD weakly interacts with bicelles at a surface that partially overlaps with the WxxxF/Y binding site. The PEX5-PEX14 interaction is largely unaffected by membrane presence (similar binding enthalpies with entropy compensation), indicating membrane docking does not reduce overall PEX5-PEX14 binding affinity. NMR spectroscopy with bicelles and nanodiscs, isothermal titration calorimetry (ITC) Frontiers in cell and developmental biology Medium 33937250
2025 Pex8 in yeast is essential for peroxisomal cargo translocation regardless of receptor/cargo recognition mechanism. Pex8 binds through a 12-fold HEAT repeat array to a short three-helical bundle in the N-terminal domain of Pex5; impairing this interaction abolishes peroxisomal protein translocation. A secondary autonomous Pex8 cargo-like interaction site exists at the C-terminal domain of Pex5, generating a bipartite interaction. The Pex5/Pex8 complex assembly enables association with the Pex2/Pex10/Pex12 E3-ubiquitin ligase complex to initiate receptor recycling. Cryo-electron microscopy structure of Pex5-Pex8 complex, mutagenesis, functional import assays in yeast bioRxiv (preprint)preprint Medium bio_10.1101_2025.08.30.673231
2025 Saccharomyces cerevisiae Eci1 can reach peroxisomes and bind Pex5 in the absence of a canonical PTS1 signal. Cryo-EM structure of yeast Pex5-Eci1 complex identified additional binding interfaces beyond the canonical PTS1-TPR interaction, revealing that some cargoes use non-canonical interaction surfaces for Pex5-mediated targeting. Cryo-electron microscopy, import assays in yeast pex5 mutants lacking PTS1 Journal of cell science Medium 40376748
2023 PEX13 loss causes accumulation of ubiquitinated PEX5 on peroxisomes and increased peroxisome-dependent ROS, both of which induce pexophagy. PEX13 protein levels are downregulated during amino acid starvation to aid pexophagy induction, establishing PEX13 as a regulator that prevents pexophagy of healthy peroxisomes by controlling ubiquitinated PEX5 accumulation. CRISPR gene editing, quantitative fluorescence microscopy, zebrafish model, autophagy assays Autophagy Medium 36541703
2009 Solution SAXS analysis of human Pex5-Pex14-PTS1 complexes revealed a 1:6 stoichiometry for Pex5:Pex14 complex. Free full-length Pex5 is monomeric in solution with an elongated, partially unfolded N-terminal domain. In the complex, the Pex5 N-terminus remains extended, with Pex14 significantly intermingled with the Pex5 moiety. Small-angle X-ray scattering (SAXS), static light scattering, titration studies The Journal of biological chemistry Medium 19584060
2003 Full-length tetrameric PEX5 binds PTS1 (lissamine-Tyr-Gln-Ser-Lys-Leu-COO-) with Kd of 35 nM. Neither Hsp70 (with or without ATP/ADP) nor the PEX12 zinc RING domain has a detectable effect on PEX5-PTS1 binding kinetics, indicating initial cargo recognition by PEX5 is a relatively simple process not regulated by these factors. Fluorescence anisotropy binding assay, purified recombinant full-length PEX5, Hsp70 addition experiments The Journal of biological chemistry Medium 12456682

Source papers

Stage 0 corpus · 94 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2000 Peroxisomal targeting signal-1 recognition by the TPR domains of human PEX5. Nature structural biology 313 11101887
2001 Mitochondrial alterations caused by defective peroxisomal biogenesis in a mouse model for Zellweger syndrome (PEX5 knockout mouse). The American journal of pathology 178 11583975
1998 Peroxisome targeting signal type 1 (PTS1) receptor is involved in import of both PTS1 and PTS2: studies with PEX5-defective CHO cell mutants. Molecular and cellular biology 177 9418886
2005 Shuttling mechanism of peroxisome targeting signal type 1 receptor Pex5: ATP-independent import and ATP-dependent export. Molecular and cellular biology 175 16314507
1999 Recombinant human peroxisomal targeting signal receptor PEX5. Structural basis for interaction of PEX5 with PEX14. The Journal of biological chemistry 154 10026185
1999 PEX12 interacts with PEX5 and PEX10 and acts downstream of receptor docking in peroxisomal matrix protein import. The Journal of cell biology 117 10562279
2001 Domain mapping of human PEX5 reveals functional and structural similarities to Saccharomyces cerevisiae Pex18p and Pex21p. The Journal of biological chemistry 103 11546814
2001 The di-aromatic pentapeptide repeats of the human peroxisome import receptor PEX5 are separate high affinity binding sites for the peroxisomal membrane protein PEX14. The Journal of biological chemistry 101 11438541
2000 Disruption of the interaction of the longer isoform of Pex5p, Pex5pL, with Pex7p abolishes peroxisome targeting signal type 2 protein import in mammals. Study with a novel Pex5-impaired Chinese hamster ovary cell mutant. The Journal of biological chemistry 91 10767287
2007 Glaucoma-causing myocilin mutants require the Peroxisomal targeting signal-1 receptor (PTS1R) to elevate intraocular pressure. Human molecular genetics 90 17317787
2012 Identification of ubiquitin-specific protease 9X (USP9X) as a deubiquitinase acting on ubiquitin-peroxin 5 (PEX5) thioester conjugate. The Journal of biological chemistry 84 22371489
2020 Spatiotemporal contact between peroxisomes and lipid droplets regulates fasting-induced lipolysis via PEX5. Nature communications 80 31996685
2015 Export-deficient monoubiquitinated PEX5 triggers peroxisome removal in SV40 large T antigen-transformed mouse embryonic fibroblasts. Autophagy 80 26086376
2011 PEX5 protein binds monomeric catalase blocking its tetramerization and releases it upon binding the N-terminal domain of PEX14. The Journal of biological chemistry 74 21976670
2009 Structural basis for competitive interactions of Pex14 with the import receptors Pex5 and Pex19. The EMBO journal 73 19197237
2013 PEX5, the shuttling import receptor for peroxisomal matrix proteins, is a redox-sensitive protein. Traffic (Copenhagen, Denmark) 71 24118911
2017 TRIM37, a novel E3 ligase for PEX5-mediated peroxisomal matrix protein import. The Journal of cell biology 67 28724525
2013 Redox-regulated cargo binding and release by the peroxisomal targeting signal receptor, Pex5. The Journal of biological chemistry 67 23902771
2017 The peroxisomal import receptor PEX5 functions as a stress sensor, retaining catalase in the cytosol in times of oxidative stress. Biochimica et biophysica acta. Molecular cell research 63 28760655
2007 Characterization of the role of the receptors PEX5 and PEX7 in the import of proteins into glycosomes of Trypanosoma brucei. Biochimica et biophysica acta 62 17320990
2015 A novel type of rhizomelic chondrodysplasia punctata, RCDP5, is caused by loss of the PEX5 long isoform. Human molecular genetics 61 26220973
2022 PEX5 translocation into and out of peroxisomes drives matrix protein import. Molecular cell 59 35931083
2017 Role of PEX5 ubiquitination in maintaining peroxisome dynamics and homeostasis. Cell cycle (Georgetown, Tex.) 52 28933989
1999 Functional heterogeneity of C-terminal peroxisome targeting signal 1 in PEX5-defective patients. Biochemical and biophysical research communications 52 10462504
2006 The peroxisomal import proteins PEX2, PEX5 and PEX7 are differently involved in Podospora anserina sexual cycle. Molecular microbiology 51 16987176
2023 PEX13 prevents pexophagy by regulating ubiquitinated PEX5 and peroxisomal ROS. Autophagy 50 36541703
2013 A novel Pex14 protein-interacting site of human Pex5 is critical for matrix protein import into peroxisomes. The Journal of biological chemistry 50 24235149
2000 Peroxisomal targeting signal-1 receptor protein PEX5 from Leishmania donovani. Molecular, biochemical, and immunocytochemical characterization. The Journal of biological chemistry 47 10788481
2011 AWP1/ZFAND6 functions in Pex5 export by interacting with cys-monoubiquitinated Pex5 and Pex6 AAA ATPase. Traffic (Copenhagen, Denmark) 46 21980954
2013 A cargo-centered perspective on the PEX5 receptor-mediated peroxisomal protein import pathway. The Journal of biological chemistry 45 23963456
2020 PEX5, a novel target of microRNA-31-5p, increases radioresistance in hepatocellular carcinoma by activating Wnt/β-catenin signaling and homologous recombination. Theranostics 44 32373215
2009 Mapping the cargo protein membrane translocation step into the PEX5 cycling pathway. The Journal of biological chemistry 42 19632994
2003 Correlating structure and affinity for PEX5:PTS1 complexes. Biochemistry 42 12578380
2018 Peroxisomal monoubiquitinated PEX5 interacts with the AAA ATPases PEX1 and PEX6 and is unfolded during its dislocation into the cytosol. The Journal of biological chemistry 40 29884772
2001 An unexpected extended conformation for the third TPR motif of the peroxin PEX5 from Trypanosoma brucei. Journal of molecular biology 39 11243819
2002 The neuronal migration defect in mice with Zellweger syndrome (Pex5 knockout) is not caused by the inactivity of peroxisomal beta-oxidation. Journal of neuropathology and experimental neurology 37 11939592
2018 PEX5 regulates autophagy via the mTORC1-TFEB axis during starvation. Experimental & molecular medicine 36 29622767
2009 Solution structure of human Pex5.Pex14.PTS1 protein complexes obtained by small angle X-ray scattering. The Journal of biological chemistry 35 19584060
2014 Ligand-induced compaction of the PEX5 receptor-binding cavity impacts protein import efficiency into peroxisomes. Traffic (Copenhagen, Denmark) 34 25369882
2002 PEX5 binds the PTS1 independently of Hsp70 and the peroxin PEX12. The Journal of biological chemistry 30 12456682
2000 A proposed model for the PEX5-peroxisomal targeting signal-1 recognition complex. Proteins 28 10713985
2017 The peroxisomal matrix protein translocon is a large cavity-forming protein assembly into which PEX5 protein enters to release its cargo. The Journal of biological chemistry 27 28765278
2013 Ubiquitination of the glycosomal matrix protein receptor PEX5 in Trypanosoma brucei by PEX4 displays novel features. Biochimica et biophysica acta 27 23994617
2021 Membrane Interactions of the Peroxisomal Proteins PEX5 and PEX14. Frontiers in cell and developmental biology 23 33937250
2023 The rice peroxisomal receptor PEX5 negatively regulates resistance to rice blast fungus Magnaporthe oryzae. Cell reports 22 37862164
2014 The unique degradation pathway of the PTS2 receptor, Pex7, is dependent on the PTS receptor/coreceptor, Pex5 and Pex20. Molecular biology of the cell 21 25009284
2018 Distinct Roles for Peroxisomal Targeting Signal Receptors Pex5 and Pex7 in Drosophila. Genetics 19 30389805
2009 Genotype-phenotype correlation in PEX5-deficient peroxisome biogenesis defective cell lines. Human mutation 19 18712838
2023 SIRT3 improved peroxisomes-mitochondria interplay and prevented cardiac hypertrophy via preserving PEX5 expression. Redox biology 18 36906951
2001 The tetratricopeptide repeat domains of human, tobacco, and nematode PEX5 proteins are functionally interchangeable with the analogous native domain for peroxisomal import of PTS1-terminated proteins in yeast. Molecular genetics and genomics : MGG 18 11361338
2003 A review of morphological techniques for detection of peroxisomal (and mitochondrial) proteins and their corresponding mRNAs during ontogenesis in mice: application to the PEX5-knockout mouse with Zellweger syndrome. Microscopy research and technique 17 12740819
2014 PEX5 and ubiquitin dynamics on mammalian peroxisome membranes. PLoS computational biology 16 24453954
2013 Pex5p stabilizes Pex14p: a study using a newly isolated pex5 CHO cell mutant, ZPEG101. The Biochemical journal 16 23009329
2012 Peroxisome deficient aP2-Pex5 knockout mice display impaired white adipocyte and muscle function concomitant with reduced adrenergic tone. Molecular genetics and metabolism 15 23141464
2020 Structure-Activity Relationship in Pyrazolo[4,3-c]pyridines, First Inhibitors of PEX14-PEX5 Protein-Protein Interaction with Trypanocidal Activity. Journal of medicinal chemistry 13 31860309
2019 Ceramide regulates interaction of Hsd17b4 with Pex5 and function of peroxisomes. Biochimica et biophysica acta. Molecular and cell biology of lipids 12 31176039
2023 Loss of pex5 sensitizes zebrafish to fasting due to deregulated mitochondria, mTOR, and autophagy. Cellular and molecular life sciences : CMLS 11 36821008
2022 The Extraction Mechanism of Monoubiquitinated PEX5 from the Peroxisomal Membrane. Journal of molecular biology 11 36442669
2021 Different contributions of the peroxisomal import protein Pex5 and Pex7 to development, stress response and virulence of insect fungal pathogen Beauveria bassiana. Journal of applied microbiology 11 34260798
2022 Diffusion and interaction dynamics of the cytosolic peroxisomal import receptor PEX5. Biophysical reports 10 36299769
2022 Pre-meiotic deletion of PEX5 causes spermatogenesis failure and infertility in mice. Cell proliferation 10 36433756
2018 Chemically monoubiquitinated PEX5 binds to the components of the peroxisomal docking and export machinery. Scientific reports 10 30375424
2014 Microporation is an efficient method for siRNA-induced knockdown of PEX5 in HepG2 cells: evaluation of the transfection efficiency, the PEX5 mRNA and protein levels and induction of peroxisomal deficiency. Histochemistry and cell biology 9 25224142
2021 A missense allele of PEX5 is responsible for the defective import of PTS2 cargo proteins into peroxisomes. Human genetics 8 33389129
2000 Peroxisomal remnant structures in Hansenula polymorpha Pex5 cells can develop into normal peroxisomes upon induction of the PTS2 protein amine oxidase. The Journal of biological chemistry 8 11050097
2021 Acyl-CoA oxidase ACOX-1 interacts with a peroxin PEX-5 to play roles in larval development of Haemonchus contortus. PLoS pathogens 7 34270617
2020 Aging lowers PEX5 levels in cortical neurons in male and female mouse brains. Molecular and cellular neurosciences 7 32777345
2005 AtLACS7 interacts with the TPR domains of the PTS1 receptor PEX5. Archives of biochemistry and biophysics 7 16256065
2021 PEX5 prevents cardiomyocyte hypertrophy via suppressing the redox-sensitive signaling pathways MAPKs and STAT3. European journal of pharmacology 6 34174269
2007 Molecular characterization of the PEX5 gene encoding peroxisomal targeting signal 1 receptor from the methylotrophic yeast Pichia methanolica. Yeast (Chichester, England) 6 17506110
2022 Structure-based design, synthesis and evaluation of a novel family of PEX5-PEX14 interaction inhibitors against Trypanosoma. European journal of medicinal chemistry 5 36194937
2022 Membrane binding and pore forming insertion of PEX5 into horizontal lipid bilayer. Biological chemistry 5 36260915
2025 PEX5 deficiency enhances radiosensitivity via MGST1-GSH detoxifying function and promotes ferroptosis in liver cancer. Science China. Life sciences 4 40614015
2024 Noncanonical and reversible cysteine ubiquitination prevents the overubiquitination of PEX5 at the peroxisomal membrane. PLoS biology 4 38470934
2023 Development of novel PEX5-PEX14 protein-protein interaction (PPI) inhibitors based on an oxopiperazine template. European journal of medicinal chemistry 4 37406382
2022 Two Pex5 Proteins With Different Cargo Specificity Are Critical for Peroxisome Function in Ustilago maydis. Frontiers in cell and developmental biology 4 35646929
2022 Small molecule mediated inhibition of protein cargo recognition by peroxisomal transport receptor PEX5 is toxic to Trypanosoma. Scientific reports 4 36038611
2021 Versatile allosteric properties in Pex5-like tetratricopeptide repeat proteins to induce diverse downstream function. Traffic (Copenhagen, Denmark) 4 33580581
2021 Association of genetic variants of TMEM135 and PEX5 in the peroxisome pathway with cutaneous melanoma-specific survival. Annals of translational medicine 4 33842617
2001 Temperature-sensitive phenotype of Chinese hamster ovary cells defective in PEX5 gene. Biochemical and biophysical research communications 4 11606046
2018 Identification of Peroxisomal Protein Complexes with PTS Receptors, Pex5 and Pex7, in Mammalian Cells. Sub-cellular biochemistry 3 30378028
2012 Processing of the glycosomal matrix-protein import receptor PEX5 of Trypanosoma brucei. Biochemical and biophysical research communications 3 23266609
1998 Cloning and sequence of a 3.835 kbp DNA fragment containing the HIS4 gene and a fragment of a PEX5-like gene from Candida albicans. Yeast (Chichester, England) 3 9778800
2024 Polymorphism in the Hsa-miR-4274 seed region influences the expression of PEX5 and enhances radiotherapy resistance in colorectal cancer. Frontiers of medicine 2 39190270
2024 Structural dynamics of the TPR domain of the peroxisomal cargo receptor Pex5 in Trypanosoma. International journal of biological macromolecules 2 39304044
2025 A cryo-electron microscopy structure of yeast Pex5 in complex with a cargo uncovers a novel binding interface. Journal of cell science 1 40376748
2025 TRIM37-mediated stabilization of PEX5 via monoubiquitination attenuates oxidative stress and demyelination in multiple sclerosis insights from EAE and LPC-induced experimental models. PloS one 1 41134761
2022 Studying the interaction between PEX5 and its full-length cargo proteins in living cells by a novel Försteŕs resonance energy transfer-based competition assay. Frontiers in cell and developmental biology 1 36407094
2026 PEX5 integrates the p38 MAPK signaling pathway and taurine metabolism to regulate senescence in lung fibroblasts. Experimental cell research 0 41794210
2025 PEX5 acts as a negative regulator of RANKL-induced osteoclastogenesis in vitro and inflammatory calvarial bone destruction in vivo. Biochemical and biophysical research communications 0 40319819
2025 Quantum mechanics-driven structure-activity relationship study of PEX5-PEX14 protein-protein interaction inhibitors based on a dibenzo[b,e]azepin-6(6H)-one scaffold. European journal of medicinal chemistry 0 40749258
2025 Detection of a Novel Homozygous PEX5 Stop-Loss Variant Associated with Zellweger Syndrome in a Highly Endogamic Family. The application of clinical genetics 0 40934063
2023 Estimating the Interaction Strength Between PTS1-Peptides and Their Receptor PEX5 in Living Cells Using Flow-Cytometer-Based FRET (flowFRET) Measurements. Methods in molecular biology (Clifton, N.J.) 0 36952203
2003 Altered antigenic disposition of peroxisomal urate oxidase in PEX5-defective Chinese hamster ovary cells. Biochemical and biophysical research communications 0 12646226

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