The Peroxin Pex14p

Abstract

Rat cDNA encoding a 376-amino acid peroxin was isolated by functional complementation of a peroxisomedeficient Chinese hamster ovary cell mutant, ZP110, of complementation group 14 (CG14). The primary sequence showed 28 and 24% amino acid identity with the yeast Pex14p from Hansenula polymorpha and Saccharomyces cerevisiae, respectively; therefore, we termed this cDNA rat PEX14 (RnPEX14). Human and Chinese hamster Pex14p showed 96 and 94% identity to rat Pex14p, except that both Pex14p comprised 377 amino acids. Pex14p was characterized as an integral membrane protein of peroxisomes, exposing its N-and Cterminal parts to the cytosol. Pex14p interacts with both Pex5p and Pex7p, the receptors for peroxisome targeting signal type 1 (PTS1) and PTS2, respectively, together with the receptors' cargoes, PTS1 and PTS2 proteins. Mutation in PEX14 from ZP161, the same CG as ZP110, was determined by reverse transcription-PCR as follows. A 133-base pair deletion at nucleotide residues 37-169 in one allele created a termination codon at 40 -42; in addition to this mutation, 103 base pairs were deleted at positions 385-487, resulting in the second termination immediately downstream the second deletion site in the other allele. Neither of these two mutant forms of Pex14p restored peroxisome biogenesis in ZP110 and ZP161, thereby demonstrating PEX14 to be responsible for peroxisome deficiency in CG14.

Glucose is toxic to glycosome-deficient trypanosomes

“…1B). Like other PEX14s (17,18,33), this molecule migrates somewhat slower than its predicted mass (50 kDa apparent vs. 40 kDa predicted). The protein was not present in the cytosolic fraction upon digitonin solubilization (Fig.…”

Disruption of the Interaction of the Longer Isoform of Pex5p, Pex5pL, with Pex7p Abolishes Peroxisome Targeting Signal Type 2 Protein Import in Mammals

“…All plasmid constructs were assessed by nucleotide sequence analysis. GST fusion proteins were expressed in E. coli and purified using glutathione-Sepharose (Amersham Pharmacia Biotech) as described (14). Purity of the fusion proteins was verified by SDS-PAGE (data not shown).…”

“…Catalase was located in numerous particles (peroxisomes) in ClPEX5L-S214F-transfected ZP139 (panel d) and ZP105 (data not shown) as well as in ClPEX5S-S214F-transfected ZP105 and ZP139 (data not shown). These morphological phenotypes (10), rat PEX6 (9), rat PEX12 (12), and rat PEX14 (14). Cells were assessed for PTS2-GFP import by fluorescence microscopy.…”

“…CHO mutants ZP105 and ZP139 represent pex5 CG2, and ZPG207 is in a PEX7-defective CG-R (CG11), the same group as fibroblasts from patients with rhizomelic chondrodysplasia punctata (RCDP). We have so far cloned eight peroxin cDNAs, PEX1, PEX2 (formerly peroxisome assembly factor-1 (PAF-1)), PEX5, PEX6, PEX12, PEX13, PEX14, and PEX19, by a functional phenotype complementation assay of CHO cell mutants (7)(8)(9)(10)(11)(12)(13)(14)(15). We also showed these PEX cDNAs, except for PEX14, to be responsible for human PBDs (7, 10 -13, 15-18).…”

Tetratricopeptide repeat domain of Yarrowia lipolytica Pex5p is essential for recognition of the type 1 peroxisomal targeting signal but does not confer full biological activity on Pex5p

“…Mammalian Pex5p and Pex7p have recently been reported to interact with Pex14p [38][39][40][41]. Loss of function of either PTS receptor leads to disease states in humans, causing neonatal adrenoleucodystrophy and Zellweger syndrome in Pex5p mutation [11] and rhizomelic chondrodysplasia punctata in Pex7p deficiency [23][24][25].…”