AAA Peroxins and Their Recruiter Pex26p Modulate the Interactions of Peroxins Involved in Peroxisomal Protein Import

Tamura, Shigehiko; Matsumoto, Naomi; Takeba, Ryota; Fujiki, Yukio

doi:10.1074/jbc.m114.588038

Cited by 37 publications

(43 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Human PEX26 also binds to PEX14 and dissociates upon PEX1-PEX6 ATPase activity (Tamura et al, 2014). Because PEX14 recruits PEX5 to the peroxisome, this finding is consistent with the hypothesis that PEX26 positions PEX1-PEX6 in proximity to PEX14-bound PEX5 to facilitate PEX5 retrotranslocation to the cytosol.…”

supporting

confidence: 82%

“…1D) results in peroxisome biogenesis disorders when compounded with other PEX1 mutations (Maxwell et al, 2005;Smith et al, 2016). PEX1 D2 mutations can confer general peroxisomal defects (Birschmann et al, 2005) and decrease ATPase activity (Gardner et al, 2015) and PEX5 export in yeast (Platta et al, 2005), reduce PEX1 binding to PEX6 in yeast (Birschmann et al, 2005) and humans (Tamura et al, 2006), and impair PEX26 disassociation from PEX14 in humans (Tamura et al, 2014). The peroxisomal defects found in our two Arabidopsis PEX1 D2 mutants indicate that this domain also is important for peroxisome function in plants.…”

Section: And G)mentioning

confidence: 77%

“…These observations suggest that PEX1 levels cannot exceed a particular level or ratio relative to PEX6. Human PEX1 can form homotrimers in the cytosol (Tamura et al, 2006) that bind PEX5 (Tamura et al, 2014), suggesting that excessive PEX1 may sequester PEX5 in the cytosol and prevent cargo delivery, leading to the observed defects. Additionally, because PEX1 was expressed from the constitutive 35S promoter, defects could be due to ectopic expression in tissues that usually do not have high PEX1 levels.…”

Section: Pex1 and Pex6 Are Interdependentmentioning

confidence: 99%

See 2 more Smart Citations

The PEX1 ATPase Stabilizes PEX6 and Plays Essential Roles in Peroxisome Biology

et al. 2017

View full text Add to dashboard Cite

A variety of metabolic pathways are sequestered in peroxisomes, conserved organelles that are essential for human and plant survival. Peroxin (PEX) proteins generate and maintain peroxisomes. The PEX1 ATPase facilitates recycling of the peroxisome matrix protein receptor PEX5 and is the most commonly affected peroxin in human peroxisome biogenesis disorders. Here, we describe the isolation and characterization of, to our knowledge, the first Arabidopsis (Arabidopsis thaliana) pex1 missense alleles: pex1-2 and pex1-3. pex1-2 displayed peroxisome-related defects accompanied by reduced PEX1 and PEX6 levels. These pex1-2 defects were exacerbated by growth at high temperature and ameliorated by growth at low temperature or by PEX6 overexpression, suggesting that PEX1 enhances PEX6 stability and vice versa. pex1-3 conferred embryo lethality when homozygous, confirming that PEX1, like several other Arabidopsis peroxins, is essential for embryogenesis. pex1-3 displayed symptoms of peroxisome dysfunction when heterozygous; this semidominance is consistent with PEX1 forming a heterooligomer with PEX6 that is poisoned by pex1-3 subunits. Blocking autophagy partially rescued PEX1/pex1-3 defects, including the restoration of normal peroxisome size, suggesting that increasing peroxisome abundance can compensate for the deficiencies caused by pex1-3 and that the enlarged peroxisomes visible in PEX1/pex1-3 may represent autophagy intermediates. Overexpressing PEX1 in wild-type plants impaired growth, suggesting that excessive PEX1 can be detrimental. Our genetic, molecular, and physiological data support the heterohexamer model of PEX1-PEX6 function in plants.

show abstract

supporting

confidence: 82%

Section: And G)mentioning

confidence: 77%

Section: Pex1 and Pex6 Are Interdependentmentioning

confidence: 99%

See 1 more Smart Citation

The PEX1 ATPase Stabilizes PEX6 and Plays Essential Roles in Peroxisome Biology

et al. 2017

View full text Add to dashboard Cite

show abstract

“…PEX15/26 is more than a simple tether; yeast PEX15 binding to the PEX1–PEX6 hexamer decreases ATPase activity (Gardner et al ., ), perhaps preventing futile ATP hydrolysis prior to client recognition for extraction. The cytosolic domain of mammalian PEX26 also binds PEX14 (Tamura et al ., ), hinting that PEX14–PEX26 interactions may help guide PEX5 from the docking complex to the export machinery.…”

Section: Introductionmentioning

confidence: 99%

Disparate peroxisome‐related defects in Arabidopsis pex6 and pex26 mutants link peroxisomal retrotranslocation and oil body utilization

et al. 2017

View full text Add to dashboard Cite

SUMMARY Catabolism of fatty acids stored in oil bodies is essential for Arabidopsis seed germination and seedling development. This fatty acid breakdown occurs in peroxisomes, organelles that sequester oxidative reactions. Import of peroxisomal enzymes is facilitated by peroxins including PEX5, a receptor that delivers cargo proteins from the cytosol to the peroxisomal matrix. After cargo delivery, a complex of the PEX1 and PEX6 ATPases and the PEX26 tail-anchored membrane protein removes ubiquitinated PEX5 from the peroxisomal membrane. We identified Arabidopsis pex6 and pex26 mutants by screening for inefficient seedling β-oxidation phenotypes. The mutants displayed distinct defects in growth, response to a peroxisomally metabolized auxin precursor, and peroxisomal protein import. The low PEX5 levels in these mutants were increased by proteasome inhibitor treatment or by combining pex26 with peroxisome-associated ubiquitination machinery mutants, suggesting that ubiquitinated PEX5 is degraded by the proteasome when PEX6 or PEX26 function is reduced. Combining pex26 with mutations that increase PEX5 levels either worsened or improved pex26 physiological and molecular defects, depending on the introduced lesion. Moreover, elevating PEX5 levels via a 35S:PEX5 transgene exacerbated pex26 defects and ameliorated the defects of only a subset of pex6 alleles, implying that decreased PEX5 is not the sole molecular deficiency in these mutants. We found peroxisomes clustered around persisting oil bodies in pex6 and pex26 seedlings, suggesting a role for peroxisomal retrotranslocation machinery in oil body utilization. The disparate phenotypes of these pex alleles may reflect unanticipated functions of the peroxisomal ATPase complex.

show abstract

“…Unlike PEX22 enhancement of PEX4 activity (El Magraoui et al, 2014), tether binding decreases PEX1-PEX6 ATPase activity in yeast (Gardner et al, 2015). In addition to tethering PEX1-PEX6, mammalian PEX26 interacts with the PEX14 docking peroxin (Tamura et al, 2014), hinting that PEX26 may bridge the import and export machinery.…”

Section: Atp-dependent Receptor Retrotranslocationmentioning

confidence: 99%