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The pathogenic peroxin Pex26p recruits the Pex1p-Pex6p AAA ATPase complexes to peroxisomes

Naomi Matsumoto1, Shigehiko Tamura, Yukio Fujiki

  • 1Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka 812-8581, Japan.

Nature Cell Biology
|April 30, 2003
PubMed

Insights

Researchers identified the PEX26 gene as the cause of a peroxisome biogenesis disorder (PBD) in complementation group 8. PEX26 is crucial for recruiting essential Pex6-Pex1 complexes to peroxisomes, restoring protein import.

Area of Science:

  • Cell Biology
  • Genetics
  • Biochemistry

Background:

  • Peroxisomes are vital single-membrane organelles involved in metabolic processes.
  • Peroxisome biogenesis disorders (PBDs) are severe genetic diseases, with the gene for complementation group 8 (CG8) previously unidentified.
  • Eleven PEX genes linked to PBDs have been isolated, leaving CG8 as the sole exception.

Purpose of the Study:

  • To identify the pathogenic gene responsible for PBD in complementation group 8.
  • To elucidate the function of the identified gene in peroxisome assembly and protein import.

Main Methods:

  • Utilized ZP167 Chinese hamster ovary (CHO) mutant cells to isolate the PEX26 gene.
  • Expressed PEX26 in fibroblasts from a PBD CG8 patient to assess restoration of peroxisomal protein import.
  • Investigated protein interactions using co-immunoprecipitation assays with Pex26, Pex6, and Pex1.
  • Visualized protein localization in normal and mutant cells using immunofluorescence microscopy.

Main Results:

  • Successfully isolated human PEX26, encoding a type II peroxisomal membrane protein.
  • PEX26 expression restored peroxisomal protein import in PBD CG8 patient fibroblasts, which harbored an inactivating Arg98Trp mutation in PEX26.
  • Pex6 and Pex1 AAA ATPases were found to co-immunoprecipitate with Pex26.
  • PEX26 expression re-established the colocalization of Pex6 and Pex1 with peroxisomes in a Pex6-dependent manner.

Conclusions:

  • PEX26 is the long-sought pathogenic gene for PBD complementation group 8.
  • Pex26 functions by recruiting the Pex6-Pex1 AAA ATPase complex to peroxisomes, which is essential for peroxisome biogenesis.
  • This discovery advances the understanding of PBDs and peroxisome assembly pathways.

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