PEX26 encodes peroxin-26, a tail-anchored peroxisomal membrane protein that functions as the membrane docking factor for the PEX1-PEX6 AAA+ ATPase complex. PEX26 directly binds PEX6 via its N-terminal cytoplasmic domain (residues 29-174) and indirectly recruits PEX1 through PEX6. The PEX1-PEX6-PEX26 complex is essential for extracting the ubiquitinated PEX5 receptor from the peroxisomal membrane after cargo delivery, thereby enabling receptor recycling and continued rounds of peroxisomal matrix protein import. PEX26 is a vertebrate-specific gene that is functionally analogous (but not homologous) to yeast PEX15. It is targeted to the peroxisomal membrane via C-terminal PEX19-binding sites. Mutations in PEX26 cause Zellweger spectrum disorders (complementation group 8), accounting for approximately 5% of peroxisome biogenesis disorder cases. PEX26 is widely expressed, with highest levels in kidney, liver, brain, and skeletal muscle.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005777 peroxisome | IBA GO_REF:0000033 | ACCEPT | Summary: PEX26 is an integral peroxisomal membrane protein. Multiple experimental studies confirm its localization to peroxisomes (PMID:12717447, PMID:16257970, PMID:16763195). The IBA annotation for peroxisome is well-supported by phylogenetic inference and consistent with all experimental evidence. However, PEX26 more specifically localizes to the peroxisomal membrane (GO:0005778), so this broader term is acceptable but less informative than the more specific IDA-supported annotations. Reason: PEX26 is a bona fide peroxisomal protein. While GO:0005778 (peroxisomal membrane) is more precise, this broader CC annotation is not incorrect and is well-supported by phylogenetic analysis across vertebrates. Multiple IDA annotations also support peroxisomal localization (PMID:12717447, PMID:16257970, PMID:16763195). Supporting Evidence: PMID:12717447 Expression of PEX26 restores peroxisomal protein import in the fibroblasts of an individual with PBD of CG8 PMID:16763195 Here we analyzed targeting of the human peroxisomal tail-anchored protein PEX26 |
| GO:0016558 protein import into peroxisome matrix | IBA GO_REF:0000033 | ACCEPT | Summary: PEX26 is essential for peroxisomal matrix protein import. PEX26-deficient cells show impaired import of both PTS1- and PTS2-targeted matrix proteins (PMID:15858711, PMID:12717447). The IBA annotation correctly captures a core biological process for PEX26. However, the more specific child term GO:0016562 (protein import into peroxisome matrix, receptor recycling) more accurately describes PEX26's specific role in this process. Reason: PEX26 is required for peroxisomal matrix protein import. While GO:0016562 (receptor recycling) is more specific to PEX26's mechanism, this broader term is not incorrect. The IBA annotation is phylogenetically sound. Multiple experimental papers confirm PEX26's role in this process (PMID:12717447, PMID:15858711, PMID:16257970). Supporting Evidence: PMID:15858711 PEX26 deficiency impairs peroxisomal import of both PTS1- and PTS2-targeted matrix proteins PMID:12717447 Expression of PEX26 restores peroxisomal protein import in the fibroblasts of an individual with PBD of CG8 |
| GO:0051117 ATPase binding | IBA GO_REF:0000033 | ACCEPT | Summary: PEX26 directly binds PEX6, an AAA+ ATPase, and indirectly recruits PEX1, another AAA+ ATPase, through PEX6 (PMID:12717447, PMID:16257970, PMID:16854980). The IBA annotation for ATPase binding is well-supported and represents a core molecular function of PEX26. Reason: PEX26 directly interacts with PEX6 (an AAA+ ATPase) and indirectly with PEX1 (also an AAA+ ATPase). This ATPase binding activity is central to PEX26's function as the membrane anchor for the PEX1-PEX6 complex. IBA is phylogenetically sound, and experimental IPI evidence from PMID:16257970 also supports this annotation. Supporting Evidence: PMID:12717447 Pex6 and Pex1 of the AAA ATPase family co-immunoprecipitate with Pex26 PMID:16257970 insufficient binding to Pex1p x Pex6p complexes...is most likely responsible for the CG8 PBDs |
| GO:0005778 peroxisomal membrane | IEA GO_REF:0000120 | ACCEPT | Summary: PEX26 is an integral peroxisomal membrane protein with a single C-terminal transmembrane domain (residues 247-267 per UniProt). This IEA annotation is correct and well-supported by multiple experimental studies demonstrating peroxisomal membrane localization (PMID:12717447, PMID:16257970). Reason: The automated annotation is correct. PEX26 is a type II integral membrane protein of the peroxisomal membrane, confirmed by multiple IDA studies. The IEA annotation is redundant with IDA annotations but not incorrect. Supporting Evidence: PMID:12717447 we have isolated human PEX26 encoding a type II peroxisomal membrane protein |
| GO:0015031 protein transport | IEA GO_REF:0000043 | ACCEPT | Summary: PEX26 is involved in protein transport -- specifically the import of peroxisomal matrix proteins. This IEA annotation from UniProt keyword mapping (Protein transport keyword) is correct but very general. More specific terms such as GO:0016558 (protein import into peroxisome matrix) or GO:0016562 (receptor recycling) better describe PEX26's role. Reason: While overly broad, this IEA annotation is not incorrect. PEX26 is involved in protein transport (specifically peroxisomal matrix protein import). The more specific annotations from IDA/IBA evidence are more informative, but this general IEA annotation is acceptable as a broader parent annotation. |
| GO:0044877 protein-containing complex binding | IEA GO_REF:0000002 | ACCEPT | Summary: PEX26 binds the PEX1-PEX6 AAA+ ATPase complex. The InterPro-derived IEA annotation for protein-containing complex binding is correct in that PEX26 binds the PEX1-PEX6 hexameric complex (PMID:16854980). However, the more specific GO:0051117 (ATPase binding) better describes the molecular function. Reason: PEX26 does bind a protein-containing complex (the PEX1-PEX6 heterohexamer). This IEA is consistent with experimental evidence from PMID:16854980 showing PEX26 binds the assembled PEX1-PEX6 complex. While ATPase binding (GO:0051117) is more specific, this broader term is acceptable for an IEA annotation. Supporting Evidence: PMID:16854980 PEX26 responsible for peroxisome biogenesis disorders of CG8 encodes Pex26p, the recruiter of Pex1p.Pex6p complexes to peroxisomes |
| GO:0045046 protein import into peroxisome membrane | IEA GO_REF:0000002 | REMOVE | Summary: This IEA annotation from InterPro suggests PEX26 is involved in protein import into the peroxisome membrane (i.e., PMP import). However, PEX26's established function is in peroxisomal matrix protein import (specifically receptor recycling after matrix protein import), not in peroxisomal membrane protein import. PEX26 itself is a PMP that is imported into the peroxisome membrane via PEX19/PEX3, but PEX26 does not facilitate PMP import. This annotation conflates PEX26 being a PMP with PEX26 functioning in PMP import. Reason: PEX26 is not involved in importing proteins into the peroxisomal membrane. PEX26's role is in peroxisomal matrix protein import via receptor recycling. PEX26 is itself a substrate of the PEX19/PEX3 PMP import pathway (PMID:16763195), but it does not facilitate PMP import for other proteins. This IEA annotation likely results from an overly broad InterPro domain annotation. Supporting Evidence: PMID:16763195 we show that PEX19 is essential for PEX26 import PMID:12717447 Pex26 recruits Pex6-Pex1 complexes to peroxisomes |
| GO:0005515 protein binding | IPI PMID:16189514 Towards a proteome-scale map of the human protein-protein in... | MARK AS OVER ANNOTATED | Summary: PMID:16189514 is a large-scale Y2H interactome mapping study (Rual et al. 2005). Protein binding is uninformative as a GO term and does not describe PEX26's specific molecular interactions. The more informative terms ATPase binding (GO:0051117) and protein-membrane adaptor activity (GO:0043495) better capture PEX26's function. Reason: Per curation guidelines, protein binding (GO:0005515) is uninformative and should be replaced with more specific MF terms. PEX26's key binding interactions are captured by GO:0051117 (ATPase binding) for its interaction with PEX1/PEX6. This large-scale screen (PMID:16189514) likely detected many non-physiological interactions alongside any real ones. |
| GO:0005515 protein binding | IPI PMID:20531392 The peroxisomal receptor Pex19p forms a helical mPTS recogni... | MARK AS OVER ANNOTATED | Summary: PMID:20531392 (Schueller et al. 2010) describes the structural basis for PEX19 recognition of mPTS signals. PEX26 is identified as a PEX19 binding partner via its C-terminal mPTS. While the interaction with PEX19 is real and physiologically relevant for PEX26 targeting to peroxisomes, protein binding is uninformative. Reason: Protein binding is uninformative. The interaction between PEX26 and PEX19 is real and relates to PEX26's targeting to peroxisomes (PMID:16763195, PMID:20531392), but should be annotated with a more specific term if one exists. PEX26 is a client of PEX19 for membrane insertion, not the other way around. |
| GO:0005515 protein binding | IPI PMID:32296183 A reference map of the human binary protein interactome. | MARK AS OVER ANNOTATED | Summary: PMID:32296183 (Luck et al. 2020) is a large-scale binary interactome mapping study. Protein binding is uninformative and the interactions detected in high-throughput screens may not reflect physiological PEX26 interactions. Reason: Protein binding is uninformative per curation guidelines. High-throughput interactome studies detect many interactions that may not be physiologically relevant to PEX26's core function. |
| GO:0005515 protein binding | IPI PMID:32814053 Interactome Mapping Provides a Network of Neurodegenerative ... | MARK AS OVER ANNOTATED | Summary: PMID:32814053 (Haenig et al. 2020) is a neurodegenerative disease interactome mapping study. Protein binding is uninformative and the interactions detected may not be specific to PEX26's function. Reason: Protein binding is uninformative per curation guidelines. This high-throughput interactome study is focused on neurodegenerative disease networks and any PEX26 interactions detected may be incidental. |
| GO:0005778 peroxisomal membrane | NAS PMID:35805150 Insights into the Structure and Function of the Pex1/Pex6 AA... | ACCEPT | Summary: PMID:35805150 (Judy et al. 2022) is a review article on PEX1/PEX6 structure and function that describes PEX26 as the membrane anchor that recruits PEX1/PEX6 to the peroxisome membrane. The NAS annotation for peroxisomal membrane is correct and consistent with multiple experimental studies. Reason: PEX26 is well-established as a peroxisomal membrane protein. Although this NAS annotation is from a review (PMID:35805150), it is consistent with primary experimental evidence (PMID:12717447, PMID:16257970) and redundant with IDA annotations. Supporting Evidence: PMID:35805150 its partner protein—named Pex15 in S. cerevisiae or PEX26 in other organisms—that recruits Pex1/Pex6 to the peroxisome membrane |
| GO:0016562 protein import into peroxisome matrix, receptor recycling | NAS PMID:35805150 Insights into the Structure and Function of the Pex1/Pex6 AA... | ACCEPT | Summary: PEX26 is a key component of the receptor export module that enables PEX5 receptor recycling after cargo delivery. PMID:35805150 states that PEX1/PEX6 is necessary to extract Pex5 from the peroxisome membrane for subsequent rounds of import, and PEX26 is the membrane anchor for this complex. GO:0016562 is the most specific and accurate term for PEX26's role in peroxisomal biology. Reason: This is the most precise BP annotation for PEX26. PEX26 anchors the PEX1-PEX6 complex that drives PEX5 receptor recycling. The review (PMID:35805150) synthesizes extensive primary literature supporting this function. This term accurately describes PEX26's specific mechanistic role within the broader process of peroxisomal matrix protein import. Supporting Evidence: PMID:35805150 Pex1/Pex6 is necessary to extract Pex5 from the peroxisome membrane for subsequent rounds of import...Receptor recycling remains the canonical role for Pex1/Pex6 across eukaryotes |
| GO:0005778 peroxisomal membrane | IDA PMID:12717447 The pathogenic peroxin Pex26p recruits the Pex1p-Pex6p AAA A... | ACCEPT | Summary: Matsumoto et al. (2003) identified PEX26 as a type II peroxisomal membrane protein with a single C-terminal transmembrane domain. They demonstrated peroxisomal membrane localization using epitope-tagged constructs and immunofluorescence. Reason: This is a core CC annotation for PEX26. The original identification paper (PMID:12717447) directly demonstrated that PEX26 is an integral protein of the peroxisomal membrane with type II topology. Supporting Evidence: PMID:12717447 we have isolated human PEX26 encoding a type II peroxisomal membrane protein of relative molecular mass 34,000 |
| GO:0016558 protein import into peroxisome matrix | IDA PMID:12717447 The pathogenic peroxin Pex26p recruits the Pex1p-Pex6p AAA A... | ACCEPT | Summary: Matsumoto et al. (2003) showed that expression of PEX26 restores peroxisomal protein import in CG8 patient fibroblasts. This directly demonstrates PEX26's requirement for peroxisomal matrix protein import. Reason: Direct experimental evidence showing PEX26 expression rescues peroxisomal protein import in PEX26-deficient cells. This is a core biological process for PEX26. Supporting Evidence: PMID:12717447 Expression of PEX26 restores peroxisomal protein import in the fibroblasts of an individual with PBD of CG8 |
| GO:0022615 protein to membrane docking | IDA PMID:12717447 The pathogenic peroxin Pex26p recruits the Pex1p-Pex6p AAA A... | ACCEPT | Summary: PEX26 recruits the PEX1-PEX6 AAA ATPase complex to the peroxisomal membrane, which can be described as a docking function. Matsumoto et al. showed that PEX6 and PEX1 colocalize with peroxisomes in wild-type cells but not in PEX26-defective cells, and that PEX26 expression restores this colocalization. This term describes PEX26's role in mediating the association of soluble PEX1-PEX6 with the peroxisomal membrane. Reason: PEX26 functions as the membrane docking receptor for the PEX1-PEX6 complex. This is a core function supported by direct evidence showing that PEX26 is required for peroxisomal localization of PEX6 and PEX1 (PMID:12717447). Supporting Evidence: PMID:12717447 Epitope-tagged Pex6 and Pex1 are discernible as puncta in normal CHO-K1 cells, but not in PEX26-defective cells. PEX26 expression in ZP167 cells re-establishes colocalization of Pex6 and Pex1 with Pex26 |
| GO:0043495 protein-membrane adaptor activity | IDA PMID:12717447 The pathogenic peroxin Pex26p recruits the Pex1p-Pex6p AAA A... | ACCEPT | Summary: PEX26 acts as an adaptor that recruits the cytosolic PEX1-PEX6 complex to the peroxisomal membrane. Matsumoto et al. demonstrated that PEX26 co-immunoprecipitates with PEX6 and PEX1, and that PEX26 expression in PEX26-deficient cells restores peroxisomal localization of PEX6 and PEX1. This is the most appropriate MF term for PEX26's core molecular function. Reason: Protein-membrane adaptor activity is the most accurate MF term for PEX26. It serves as an integral membrane protein that recruits a soluble protein complex (PEX1-PEX6) to the peroxisomal membrane. This is the central molecular function of PEX26. Supporting Evidence: PMID:12717447 Pex26 recruits Pex6-Pex1 complexes to peroxisomes |
| GO:0043495 protein-membrane adaptor activity | IDA PMID:16257970 Mutations in the peroxin Pex26p responsible for peroxisome b... | ACCEPT | Summary: Furuki et al. (2006) characterized disease-causing PEX26 mutations and showed they impair PEX26's interaction with the PEX1-PEX6 complex, its stability, and/or its peroxisomal localization. This further validates PEX26's protein-membrane adaptor function by showing that mutations disrupting this function cause disease. Reason: Additional experimental support for PEX26's core MF of protein-membrane adaptor activity. Disease-causing mutations that disrupt PEX26's binding to PEX1-PEX6 or its membrane localization cause peroxisome biogenesis disorders (PMID:16257970). Supporting Evidence: PMID:16257970 the instability, insufficient binding to Pex1p x Pex6p complexes, or mislocalization of patient-derived Pex26p mutants is most likely responsible for the CG8 PBDs |
| GO:0005829 cytosol | TAS Reactome:R-HSA-9603775 | KEEP AS NON CORE | Summary: This Reactome annotation reflects PEX26's involvement in the PEX3:PEX19:class I PMP dissociation reaction, where PEX19-bound PMPs (including PEX26) transit through the cytosol before membrane insertion. PEX26 is synthesized in the cytosol and transiently present there before insertion into the peroxisomal membrane via the PEX19/PEX3 pathway. However, PEX26's functional localization is the peroxisomal membrane. Reason: PEX26 does transit through the cytosol as part of the PEX19-mediated PMP import pathway, so the annotation is technically correct. However, the cytosol is not the primary functional location of PEX26; it is a transient localization during membrane targeting. Interestingly, Weller et al. (PMID:15858711) showed that a cytosolic PEX26 isoform (PEX26-deltaex5) lacking the transmembrane domain is functional, suggesting some PEX26 activity can occur in the cytosol. Supporting Evidence: PMID:15858711 PEX26-Deltaex5 rescues peroxisome biogenesis in PEX26-deficient cells as efficiently as does PEX26-FL |
| GO:0005829 cytosol | TAS Reactome:R-HSA-9603784 | KEEP AS NON CORE | Summary: Another Reactome annotation for PEX19:class I PMP binding to PEX3, reflecting the cytosolic transit of PEX26 during PMP import. Same considerations as above. Reason: Cytosolic localization is transient for PEX26 during its PEX19-mediated targeting to peroxisomes. Not the primary functional location but technically correct. |
| GO:0005829 cytosol | TAS Reactome:R-HSA-9603804 | KEEP AS NON CORE | Summary: Reactome annotation reflecting PEX19 binding to class I PMPs (including PEX26) in the cytosol. Same considerations as the other cytosol annotations. Reason: Cytosolic localization is a transient step in PEX26's biogenesis pathway. Not its primary functional location. |
| GO:0005778 peroxisomal membrane | TAS Reactome:R-HSA-9033499 | ACCEPT | Summary: This Reactome reaction describes PEX1:PEX6:PEX26:ZFAND6 dissociating Ub:PEX5L and PEX7 from the docking/translocation module (PEX14:PEX13:PEX2:PEX10:PEX12). PEX26 is correctly annotated to the peroxisomal membrane in this context as part of the receptor export module. Reason: Peroxisomal membrane is the correct functional localization for PEX26 during receptor recycling. This Reactome annotation accurately reflects PEX26's role as part of the membrane-bound PEX1-PEX6-PEX26 receptor export module. |
| GO:0005778 peroxisomal membrane | TAS Reactome:R-HSA-9033516 | ACCEPT | Summary: Reactome reaction describing binding of the ubiquitinated PEX5L:PEX7 docking complex to PEX1:PEX6:PEX26 and ZFAND6 at the peroxisomal membrane. Correctly places PEX26 at the peroxisomal membrane. Reason: Correct localization of PEX26 during its functional role in receptor recycling at the peroxisomal membrane. Redundant with IDA annotation but consistent. |
| GO:0005778 peroxisomal membrane | TAS Reactome:R-HSA-9033533 | ACCEPT | Summary: Reactome reaction for PEX5S/L receptor recycling at the peroxisomal membrane. Same context as other Reactome peroxisomal membrane annotations. Reason: Correct and consistent with PEX26's established peroxisomal membrane localization. |
| GO:0005778 peroxisomal membrane | TAS Reactome:R-HSA-9603775 | ACCEPT | Summary: Reactome reaction for PEX3:PEX19:class I PMP dissociation. PEX26 is annotated to peroxisomal membrane as the destination of PMP import. Correct. Reason: PEX26 is correctly localized to the peroxisomal membrane after PEX19/PEX3-mediated insertion. |
| GO:0005777 peroxisome | IDA PMID:16763195 Targeting of the tail-anchored peroxisomal membrane proteins... | ACCEPT | Summary: Halbach et al. (2006) analyzed PEX26 targeting to peroxisomes and showed it occurs through C-terminal PEX19-binding sites. They demonstrated PEX26 localizes to peroxisomes and identified two PEX19-binding sites required for correct targeting. Reason: Direct experimental evidence for PEX26 localization to peroxisomes. While GO:0005778 (peroxisomal membrane) is more specific, the broader peroxisome annotation is not incorrect and is supported by the immunofluorescence data in this study. Supporting Evidence: PMID:16763195 Here we analyzed targeting of the human peroxisomal tail-anchored protein PEX26. Its C-terminal-targeting signal contains two binding sites for PEX19 |
| GO:0016558 protein import into peroxisome matrix | IDA PMID:16257970 Mutations in the peroxin Pex26p responsible for peroxisome b... | ACCEPT | Summary: Furuki et al. (2006) showed that pathogenic PEX26 mutations impair peroxisomal protein import, further confirming PEX26's essential role in this process. Temperature-sensitive mutations showed milder phenotypes than null mutations. Reason: Direct experimental evidence that PEX26 mutations impair peroxisomal matrix protein import. This complements the IDA annotation from PMID:12717447. Supporting Evidence: PMID:16257970 Pex26p functions in recruiting to peroxisomes the complexes of the AAA ATPase peroxins, Pex1p and Pex6p |
| GO:0005515 protein binding | IPI PMID:16257970 Mutations in the peroxin Pex26p responsible for peroxisome b... | MARK AS OVER ANNOTATED | Summary: PMID:16257970 documents PEX26 interactions with PEX1 and PEX6 in the context of disease-causing mutations. The specific interaction with PEX6/PEX1 is better captured by GO:0051117 (ATPase binding) which is already annotated. Reason: Protein binding is uninformative. PEX26's interaction with PEX1/PEX6 is better captured by GO:0051117 (ATPase binding) and GO:0043495 (protein-membrane adaptor activity), both of which are already annotated from this same reference. |
| GO:0005515 protein binding | IPI PMID:16763195 Targeting of the tail-anchored peroxisomal membrane proteins... | MARK AS OVER ANNOTATED | Summary: PMID:16763195 (Halbach et al. 2006) demonstrates PEX26 interaction with PEX19 through C-terminal binding sites. This is a real and physiologically important interaction for PEX26 membrane targeting, but protein binding is uninformative. Reason: Protein binding is uninformative per curation guidelines. The PEX26-PEX19 interaction is real and important for PEX26 targeting, but should ideally be annotated with a more specific term. PEX26 is a client/cargo of PEX19 for membrane insertion. |
| GO:0005777 peroxisome | IDA PMID:16257970 Mutations in the peroxin Pex26p responsible for peroxisome b... | ACCEPT | Summary: Furuki et al. (2006) confirmed PEX26 peroxisomal localization and showed that certain disease-causing mutations impair this localization. Reason: Additional IDA evidence for PEX26 peroxisomal localization. Disease mutations that impair localization provide further support for the physiological significance of this annotation. Supporting Evidence: PMID:16257970 mislocalization of patient-derived Pex26p mutants is most likely responsible for the CG8 PBDs |
| GO:0051117 ATPase binding | IPI PMID:16257970 Mutations in the peroxin Pex26p responsible for peroxisome b... | ACCEPT | Summary: Furuki et al. (2006) characterized PEX26 disease mutations and showed they impair interaction with the PEX1-PEX6 AAA ATPase complex. This provides strong experimental evidence for PEX26's ATPase binding activity. Reason: Direct experimental IPI evidence for PEX26 binding to PEX1/PEX6 AAA ATPases. Disease mutations that reduce this binding cause peroxisome biogenesis disorders, confirming the physiological importance of this interaction. Supporting Evidence: PMID:16257970 insufficient binding to Pex1p x Pex6p complexes...is most likely responsible for the CG8 PBDs |
| GO:0005515 protein binding | IPI PMID:15713480 Analysis of human Pex19p's domain structure by pentapeptide ... | MARK AS OVER ANNOTATED | Summary: PMID:15713480 (Fransen et al. 2005) analyzed PEX19 domain structure and identified PEX26 as one of multiple PMPs that interact with PEX19's C-terminal domain. This reflects the PEX19-PEX26 interaction for membrane targeting. Protein binding is uninformative. Reason: Protein binding is uninformative per curation guidelines. The PEX19-PEX26 interaction is documented but better captured by more specific terms. PEX26 is a client of PEX19 for peroxisomal membrane insertion. Supporting Evidence: PMID:15713480 a carboxy-terminal domain that interacts with multiple PMPs including Pex3p, Pex11pbeta, Pex12p, Pex13p, Pex16p, and Pex26p |
| GO:0005777 peroxisome | IDA PMID:15858711 Alternative splicing suggests extended function of PEX26 in ... | ACCEPT | Summary: Weller et al. (2005) showed full-length PEX26 localizes to peroxisomes but the alternatively spliced PEX26-deltaex5 (lacking the transmembrane domain) is cytosolic yet functional. This study confirms peroxisomal localization of the full-length protein. Reason: IDA evidence for PEX26 peroxisomal localization from the full-length protein. While an alternatively spliced cytosolic isoform also exists, the main isoform is peroxisomal. Supporting Evidence: PMID:15858711 it encodes an integral peroxisomal membrane protein with a single C-terminal transmembrane domain and a cytosolic N-terminus |
| GO:0016558 protein import into peroxisome matrix | IMP PMID:15858711 Alternative splicing suggests extended function of PEX26 in ... | ACCEPT | Summary: Weller et al. (2005) performed quantitative studies showing PEX26-deficient cells have substantial defects in import of PTS1-targeted proteins (PECI, HAOX1, catalase) and PTS2-targeted proteins (PAHX). They showed both PTS1 and PTS2 import are impaired in CG8 cells, correcting earlier reports that only PTS2 and catalase import were affected. Reason: Strong IMP evidence from quantitative import assays showing PEX26 deficiency impairs both PTS1 and PTS2 peroxisomal matrix protein import. This is a core function. Supporting Evidence: PMID:15858711 PEX26 deficiency impairs peroxisomal import of both PTS1- and PTS2-targeted matrix proteins PMID:15858711 our results show a clear and substantial defect in all three PTS1-targeted reporters, most severe for catalase but substantial for PECI and HAOX1 |
| GO:0005515 protein binding | IPI PMID:16854980 Dynamic and functional assembly of the AAA peroxins, Pex1p a... | MARK AS OVER ANNOTATED | Summary: PMID:16854980 (Tamura et al. 2006) studied the dynamic assembly of PEX1, PEX6, and PEX26. PEX26 interaction with PEX1/PEX6 is better captured by GO:0051117 (ATPase binding) and GO:0043495 (protein-membrane adaptor activity). Protein binding is uninformative. Reason: Protein binding is uninformative per curation guidelines. The PEX26-PEX1/PEX6 interactions described in PMID:16854980 are better captured by the already-annotated GO:0051117 (ATPase binding) and GO:0044877 (protein-containing complex binding). |
| GO:0044877 protein-containing complex binding | IDA PMID:16854980 Dynamic and functional assembly of the AAA peroxins, Pex1p a... | ACCEPT | Summary: Tamura et al. (2006) demonstrated that PEX26 binds the assembled PEX1-PEX6 complex and showed that endogenous PEX6 and PEX26 are predominantly localized on peroxisomes, while PEX1 forms homo-oligomers in the cytoplasm that undergo conformational change upon interaction with PEX6. Reason: PEX26 binds the PEX1-PEX6 heterohexameric complex. This IDA annotation captures PEX26's ability to bind a multi-subunit protein complex, which is its core function as the membrane docking receptor for the PEX1-PEX6 ATPase complex. Supporting Evidence: PMID:16854980 PEX26 responsible for peroxisome biogenesis disorders of CG8 encodes Pex26p, the recruiter of Pex1p.Pex6p complexes to peroxisomes PMID:16854980 endogenous Pex1p was partly localized likely as a homo-oligomer in the cytoplasm, while Pex6p and Pex26p were predominantly localized on peroxisomes |
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