High impact information on PEX26

• Epitope-tagged Pex6 and Pex1 are discernible as puncta in normal CHO-K1 cells, but not in PEX26-defective cells [1].
• Here we have isolated human PEX26 encoding a type II peroxisomal membrane protein of relative molecular mass 34,000 (M(r) 34K) by using ZP167 cells, a Chinese hamster ovary (CHO) mutant cell line [1].
• Expression of PEX26 restores peroxisomal protein import in the fibroblasts of an individual with PBD of CG8 [1].
• This individual possesses a homozygous, inactivating pathogenic point mutation, Arg98Trp, in Pex26 [1].
• They proposed that PEX26 functions as the peroxisomal docking factor for the PEX1/PEX6 heterodimer [2].

Biological context of PEX26

• PEX26 responsible for peroxisome biogenesis disorders of CG8 encodes Pex26p, the recruiter of Pex1p.Pex6p complexes to peroxisomes [3].
• These findings confirm that the degree of temperature sensitivity in pex26 cell lines is predictive of the clinical phenotype in patients with PEX26 deficiency [4].
• Alternative splicing suggests extended function of PEX26 in peroxisome biogenesis [2].
• We studied the PEX26 genotype in fibroblasts of eight CG8 patients--four with the ZS phenotype, two with NALD, and two with IRD [4].

Anatomical context of PEX26

• We found PEX26-Mito localized to the mitochondria and directed all detectable PEX6 and a fraction of PEX1 to this extraperoxisomal location; yet PEX26-Mito retains the full ability to rescue peroxisome biogenesis in PEX26-deficient cells [2].

Associations of PEX26 with chemical compounds

• Although the PEX19-binding site containing the TMD targeted to peroxisomes to some extent, the luminal site proved essential for correct targeting of the full-length protein, as it prevented PEX26 from mislocalization to mitochondria [5].

Other interactions of PEX26

• Mutations in novel peroxin gene PEX26 that cause peroxisome-biogenesis disorders of complementation group 8 provide a genotype-phenotype correlation [4].
• Pex19p interacts with multiple membrane peroxins, including other membrane biogenesis peroxins, Pex16p and Pex26p, involved in matrix protein import [6].
• To test our observation that a peroxisomal location is not required for PEX26 function, we made a chimeric protein (PEX26-Mito) with PEX26 as its N-terminus and the targeting segment of a mitochondrial outer membrane protein (OMP25) at its C-terminus [2].

References