Dynamic and functional assembly of the AAA peroxins, Pex1p and Pex6p, and their membrane receptor Pex26p involved in shuttling of the PTS1 receptor Pex5p in peroxisome biogenesis

2008 ◽  
Vol 36 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Yukio Fujiki ◽  
Non Miyata ◽  
Naomi Matsumoto ◽  
Shigehiko Tamura
Keyword(s):  
Atp Hydrolysis ◽  
Zellweger Syndrome ◽  
Complementation Group ◽  
Peroxisome Biogenesis ◽  
Aaa Atpase ◽  
Causal Genes ◽  
Signal Type ◽  
Targeting Signal ◽  
Membrane Bound

The peroxisome is a single-membrane-bound organelle found in eukaryotes. The functional importance of peroxisomes in humans is highlighted by peroxisome-deficient PBDs (peroxisome biogenesis disorders), such as Zellweger syndrome. Two AAA (ATPase associated with various cellular activities) peroxins, Pex1p and Pex6p, are encoded by PEX1 and PEX6, the causal genes for CG (complementation group) 1 and CG4 PBDs respectively. PEX26, which is responsible for CG8 PBDs, codes for Pex26p, the recruiter of Pex1p–Pex6p complexes to peroxisomes. We recently assigned the binding regions between human Pex1p and Pex6p and elucidated the pivotal roles that the AAA cassettes, D1 and D2 domains, play in Pex1p–Pex6p interaction and in peroxisome biogenesis. ATP binding to both AAA cassettes of Pex1p and Pex6p was a prerequisite for the Pex1p–Pex6p interaction and peroxisomal localization, but ATP hydrolysis by the D2 domains was not required. Pex1p exists in two distinct oligomeric forms, a homo-oligomer in the cytosol and a hetero-oligomer on peroxisome membranes, with these possibly having distinct functions in peroxisome biogenesis. AAA peroxins are involved in the export from peroxisomes of Pex5p, the PTS1 (peroxisome-targeting signal type 1) receptor.

Phenotype–genotype relationships in peroxisome biogenesis disorders of PEX1-defective complementation group 1 are defined by Pex1p–Pex6p interaction

2001 ◽  
Vol 357 (2) ◽  
pp. 417-426 ◽  
Author(s):  
Shigehiko TAMURA ◽  
Naomi MATSUMOTO ◽  
Atsushi IMAMURA ◽  
Nobuyuki SHIMOZAWA ◽  
Yasuyuki SUZUKI ◽  
...  
Keyword(s):  
Zellweger Syndrome ◽  
Complementation Group ◽  
Temperature Sensitive ◽  
Permissive Temperature ◽  
Peroxisome Biogenesis ◽  
Causative Gene ◽  
Aaa Atpase ◽  
Peroxisome Biogenesis Disorders ◽  
The Stability

The peroxisome biogenesis disorders (PBDs), including Zellweger syndrome (ZS), neonatal adrenoleucodystrophy (NALD) and infantile Refsum disease (IRD), are fatal autosomal recessive diseases caused by impaired peroxisome biogenesis, of which 12 genotypes have been reported. ZS patients manifest the severest clinical and biochemical abnormalities, whereas those with NALD and IRD show less severity and the mildest features respectively. We have reported previously that temperature-sensitive peroxisome assembly is responsible for the mildness of the clinical features of IRD. PEX1 is the causative gene for PBDs of complementation group E (CG-E, CG1 in the U.S.A. and Europe), the PBDs of highest incidence, encoding the peroxin Pex1p of the AAA ATPase family. It has been also reported that Pex1p and Pex6p interact with each other. In the present study we investigated phenotype–genotype relationships of CG1 PBDs. Pex1p from IRD such as Pex1p with the most frequently identified mutation at G843D was largely degraded in vivo at 37°C, whereas a normal level of Pex1p was detectable at the permissive temperature. In contrast, PEX1 proteins derived from ZS patients, including proteins with a mutation at L664P or the deletion of residues 634–690, were stably present at both temperatures. Pex1p-G843D interacted with Pex6p at approx. 50% of the level of normal Pex1p, whereas Pex1p from ZS patients mostly showing non-temperature-sensitive peroxisome biogenesis hardly bound to Pex6p. Taking these results together, we consider it most likely that the stability of Pex1p reflects temperature-sensitive peroxisome assembly in IRD fibroblasts. Failure in Pex1p–Pex6p interaction gives rise to more severe abnormalities, such as those manifested by patients with ZS.

scholarly journals Predicting the Function and Subcellular Location ofCaenorhabditis elegansProteins Similar toSaccharomyces cerevisiaeβ-Oxidation Enzymes

Yeast ◽  
2000 ◽  
Vol 1 (3) ◽  
pp. 188-200 ◽  
Author(s):  
Aner Gurvitz ◽  
Sigrid Langer ◽  
Martin Piskacek ◽  
Barbara Hamilton ◽  
Helmut Ruis ◽  
...  
Keyword(s):  
Zellweger Syndrome ◽  
Model Organism ◽  
Subcellular Location ◽  
Peroxisomal Disorders ◽  
C Elegans ◽  
Peroxisomal Targeting ◽  
Signal Type ◽  
Targeting Signal

The role of peroxisomal processes in the maintenance of neurons has not been thoroughly investigated. We propose usingCaenorhabditis elegansas a model organism for studying the molecular basis underlying neurodegeneration in certain human peroxisomal disorders, e.g. Zellweger syndrome, since the nematode neural network is well characterized and relatively simple in function. Here we have identifiedC. elegansPEX-5 (C34C6.6) representing the receptor for peroxisomal targeting signal type 1 (PTS1), defective in patients with such disorders. PEX-5 interacted strongly in a two-hybrid assay with Gal4p–SKL, and a screen using PEX-5 identified interaction partners that were predominantly terminated with PTS1 or its variants. A list ofC. elegansproteins with similarities to well-characterized yeast β-oxidation enzymes was compiled by homology probing. The possible subcellular localization of these orthologues was predicted using an algorithm based on trafficking signals. Examining the C termini of selected nematode proteins for PTS1 function substantiated predictions made regarding the proteins' peroxisomal location. It is concluded that the eukaryotic PEX5-dependent route for importing PTS1-containing proteins into peroxisomes is conserved in nematodes.C. elegansmight emerge as an attractive model system for studying the importance of peroxisomes and affiliated processes in neurodegeneration, and also for studying a β-oxidation process that is potentially compartmentalized in both mitochondria and peroxisomes.

scholarly journals Shuttling Mechanism of Peroxisome Targeting Signal Type 1 Receptor Pex5: ATP-Independent Import and ATP-Dependent Export

2005 ◽  
Vol 25 (24) ◽  
pp. 10822-10832 ◽  
Author(s):  
Non Miyata ◽  
Yukio Fujiki
Keyword(s):  
Molecular Mechanisms ◽  
Protein Complexes ◽  
Polyacrylamide Gel Electrophoresis ◽  
Supernatant Fraction ◽  
Aaa Atpase ◽  
Native Polyacrylamide Gel Electrophoresis ◽  
Signal Type ◽  
A Cell ◽  
Targeting Signal

ABSTRACT Peroxisomal matrix proteins are posttranslationally imported into peroxisomes with the peroxisome-targeting signal 1 receptor, Pex5. The longer isoform of Pex5, Pex5L, also transports Pex7-PTS2 protein complexes. After unloading the cargoes, Pex5 returns to the cytosol. To address molecular mechanisms underlying Pex5 functions, we constructed a cell-free Pex5 translocation system with a postnuclear supernatant fraction from CHO cell lines. In assays using the wild-type CHO-K1 cell fraction, 35S-labeled Pex5 was specifically imported into and exported from peroxisomes with multiple rounds. 35S-Pex5 import was also evident using peroxisomes isolated from rat liver. ATP was not required for 35S-Pex5 import but was indispensable for export. 35S-Pex5 was imported neither to peroxisome remnants from RING peroxin-deficient cell mutants nor to those from pex14 cells lacking a Pex5-docking site. In contrast, 35S-Pex5 was imported into the peroxisome remnants of PEX1-, PEX6-, and PEX26-defective cell mutants, including those from patients with peroxisome biogenesis disorders, from which, however, 35S-Pex5 was not exported, thereby indicating that Pex1 and Pex6 of the AAA ATPase family and their recruiter, Pex26, were essential for Pex5 export. Moreover, we analyzed the 35S-Pex5-associated complexes on peroxisomal membranes by blue-native polyacrylamide gel electrophoresis. 35S-Pex5 was in two distinct, 500- and 800-kDa complexes comprising different sets of peroxins, such as Pex14 and Pex2, implying that Pex5 transited between the subcomplexes. Together, results indicated that Pex5 most likely enters peroxisomes, changes its interacting partners, and then exits using ATP energy.

scholarly journals Recognition of Peroxisomal Targeting Signal Type 1 by the Import Receptor Pex5p

2001 ◽  
Vol 276 (18) ◽  
pp. 15034-15041 ◽  
Author(s):  
André T. J. Klein ◽  
Phil Barnett ◽  
Gina Bottger ◽  
Daphne Konings ◽  
Henk F. Tabak ◽  
...  
Keyword(s):  
Peroxisomal Targeting ◽  
Signal Type ◽  
Targeting Signal ◽  
Peroxisomal Targeting Signal ◽  
Import Receptor

scholarly journals Predicting the Function and Subcellular Location of Caenorhabditis elegans Proteins Similar to Saccharomyces cerevisiae β-Oxidation Enzymes

Yeast ◽  
2000 ◽  
Vol 1 (3) ◽  
pp. 188-200
Author(s):  
Aner Gurvitz ◽  
Sigrid Langer ◽  
Martin Piskacek ◽  
Barbara Hamilton ◽  
Helmut Ruis ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Zellweger Syndrome ◽  
Model Organism ◽  
Subcellular Location ◽  
Peroxisomal Disorders ◽  
C Elegans ◽  
Peroxisomal Targeting ◽  
Signal Type ◽  
Targeting Signal

The role of peroxisomal processes in the maintenance of neurons has not been thoroughly investigated. We propose using Caenorhabditis elegans as a model organism for studying the molecular basis underlying neurodegeneration in certain human peroxisomal disorders, e.g. Zellweger syndrome, since the nematode neural network is well characterized and relatively simple in function. Here we have identified C. elegans PEX-5 (C34C6.6) representing the receptor for peroxisomal targeting signal type 1 (PTS1), defective in patients with such disorders. PEX-5 interacted strongly in a two-hybrid assay with Gal4p–SKL, and a screen using PEX-5 identified interaction partners that were predominantly terminated with PTS1 or its variants. A list of C. elegans proteins with similarities to well-characterized yeast β-oxidation enzymes was compiled by homology probing. The possible subcellular localization of these orthologues was predicted using an algorithm based on trafficking signals. Examining the C termini of selected nematode proteins for PTS1 function substantiated predictions made regarding the proteins' peroxisomal location. It is concluded that the eukaryotic PEX5-dependent route for importing PTS1-containing proteins into peroxisomes is conserved in nematodes. C. elegans might emerge as an attractive model system for studying the importance of peroxisomes and affiliated processes in neurodegeneration, and also for studying a β-oxidation process that is potentially compartmentalized in both mitochondria and peroxisomes.

scholarly journals Hsp70 regulates the interaction between the peroxisome targeting signal type 1 (PTS1)-receptor Pex5p and PTS1

2001 ◽  
Vol 357 (1) ◽  
pp. 157 ◽  
Author(s):  
Tomoyuki HARANO ◽  
Shizuko NOSE ◽  
Rumiko UEZU ◽  
Nobuyoshi SHIMIZU ◽  
Yukio FUJIKI
Keyword(s):  
Signal Type ◽  
Targeting Signal

scholarly journals Peroxisome biogenesis and positioning

2010 ◽  
Vol 38 (3) ◽  
pp. 807-816 ◽  
Author(s):  
Alison Baker ◽  
Imogen A. Sparkes ◽  
Laura-Anne Brown ◽  
Catherine O'Leary-Steele ◽  
Stuart L. Warriner
Keyword(s):  
Endoplasmic Reticulum ◽  
Degradation Pathway ◽  
Matrix Proteins ◽  
Peroxisome Biogenesis ◽  
Environmental Signals ◽  
Targeting Signal ◽  
Membrane Bound ◽  
Plant Life Cycle ◽  
Peroxisome Membrane

Plant peroxisomes are extremely dynamic, moving and undergoing changes of shape in response to metabolic and environmental signals. Matrix proteins are imported via one of two import pathways, depending on the targeting signal within the protein. Each pathway has a specific receptor but utilizes common membrane-bound translocation machinery. Current models invoke receptor recycling, which may involve cycles of ubiquitination. Some components of the import machinery may also play a role in proteolytic turnover of matrix proteins, prompting parallels with the endoplasmic-reticulum-associated degradation pathway. Peroxisome membrane proteins, some of which are imported post-translationally, others of which may traffic to peroxisomes via the endoplasmic reticulum, use distinct proteinaceous machinery. The isolation of mutants defective in peroxisome biogenesis has served to emphasize the important role of peroxisomes at all stages of the plant life cycle.

scholarly journals PEX12, the Pathogenic Gene of Group III Zellweger Syndrome: cDNA Cloning by Functional Complementation on a CHO Cell Mutant, Patient Analysis, and Characterization of Pex12p

1998 ◽  
Vol 18 (7) ◽  
pp. 4324-4336 ◽  
Author(s):  
Kanji Okumoto ◽  
Nobuyuki Shimozawa ◽  
Atsusi Kawai ◽  
Shigehiko Tamura ◽  
Toshiro Tsukamoto ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Zellweger Syndrome ◽  
Complementation Group ◽  
Functional Complementation ◽  
Peroxisome Biogenesis ◽  
Cho Cell ◽  
Site Mutation ◽  
Transient Transfection Assay ◽  
Group Iii ◽  
Pathogenic Gene

ABSTRACT Rat PEX12 cDNA was isolated by functional complementation of peroxisome deficiency of a mutant CHO cell line, ZP109 (K. Okumoto, A. Bogaki, K. Tateishi, T. Tsukamoto, T. Osumi, N. Shimozawa, Y. Suzuki, T. Orii, and Y. Fujiki, Exp. Cell Res. 233:11–20, 1997), using a transient transfection assay and an ectopic, readily visible marker, green fluorescent protein. This cDNA encodes a 359-amino-acid membrane protein of peroxisomes with two transmembrane segments and a cysteine-rich zinc finger, the RING motif. A stable transformant of ZP109 with the PEX12 was morphologically and biochemically restored for peroxisome biogenesis. Pex12p was shown by expression of bona fide as well as epitope-tagged Pex12p to expose both N- and C-terminal regions to the cytosol. Fibroblasts derived from patients with the peroxisome deficiency Zellweger syndrome of complementation group III (CG-III) were also complemented for peroxisome biogenesis with PEX12. Two unrelated patients of this group manifesting peroxisome deficiency disorders possessed homozygous, inactivating PEX12mutations: in one, Arg180Thr by one point mutation, and in the other, deletion of two nucleotides in codons for 291Asn and292Ser, creating an apparently unchanged codon for Asn and a codon 292 for termination. These results indicate that the gene encoding peroxisome assembly factor Pex12p is a pathogenic gene of CG-III peroxisome deficiency. Moreover, truncation and site mutation studies, including patient PEX12analysis, demonstrated that the cytoplasmically oriented N- and C-terminal parts of Pex12p are essential for biological function.

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