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Gene Review

PEX7  -  peroxisomal biogenesis factor 7

Homo sapiens

Synonyms: PBD9B, PTS2 receptor, PTS2R, Peroxin-7, Peroxisomal targeting signal 2 receptor, ...
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Disease relevance of PEX7


High impact information on PEX7

  • Peroxisomal targeting signals (PTSs) are recognized by predominantly cytosolic receptors, Pex5p and Pex7p [4].
  • A mutation resulting in C-terminal truncation of PEX7 cosegregates with the disease and expression of PEX7 in RCDP fibroblasts from CG11 rescues the PTS2 protein import deficiency [5].
  • Human PEX7 encodes the peroxisomal PTS2 receptor and is responsible for rhizomelic chondrodysplasia punctata [6].
  • In a collection of 36 RCDP probands, we found two inactivating PEX7 mutations: one, L292ter, was present in 26 of the probands, all with a severe phenotype; the second, A218V, was present in three probands, including two with a milder phenotype [6].
  • We conclude that PEX7 is responsible for RCDP (PBD CG11) and suggest a founder effect may explain the high frequency of L292ter [6].

Biological context of PEX7


Anatomical context of PEX7

  • In this work, we found that Pex5pL directly interacts with the PTS2 receptor Pex7p, carrying its cargo PTS2 protein in the cytosol [9].
  • Pex5pL-(Pex7p-PTS2 protein) complexes were detectable in wild-type CHO-K1 cells and were apparently more stable in pex14 CHO cells deficient in the entry site of the matrix proteins, whereas only the Pex7p-PTS2 protein complex was discernible in a Pex5pL-defective pex5 CHO mutant [10].
  • Retinal photoreceptor dystrophies (RD) are a highly heterogeneous group of genetic disorders of the retina, representing the most frequently inherited form of visual handicap, affecting approximately 1.5 million people world wide [11].
  • Therefore, ZPEG227 is a pex7 mutant possessing a newly identified mutation in mammalian pex7 cell lines [12].

Associations of PEX7 with chemical compounds

  • The interaction is reduced upon cysteine alkylation and is impaired upon truncation of the N-terminus of Pex7p [13].
  • NH2-terminal regions of Pex13p are required for its interaction with the PTS2-receptor while the COOH-terminal SH3 domain alone is sufficient to mediate its interaction with the PTS1-receptor [14].
  • Two of eight patients with ZS, two of four with RCDP, and all of three classical Refsum patients showed increased levels of phytanic acid [15].
  • AR-RCDP fibroblasts also showed a two- to seven-fold increase in the rate of hexadecanol synthesis, which was associated with an increase in the activity of acyl-CoA reductase [16].

Physical interactions of PEX7

  • Pex5pL transports PTS1 proteins and Pex7p-PTS2 cargo complexes to the initial Pex5p-docking site, Pex14p, on peroxisome membranes, while Pex5pS translocates only PTS1 cargoes [17].

Other interactions of PEX7


Analytical, diagnostic and therapeutic context of PEX7

  • To relate PEX7 genotype and phenotype, we evaluated the consequence of the disease mutation on PEX7 RNA by Northern analysis and RT/PCR [8].
  • Pex7p was eluted as a monomer in gel filtration chromatography [10].
  • Normal human PEX7 expression rescues the cellular defects in cultured RCDP cells, and cDNA sequence analysis has identified a variety of PEX7 mutations in RCDP patients, including a deletion of 100 nucleotides, probably due to a splice site mutation, and a prevalent nonsense mutation which results in loss of the carboxyterminal 32 amino acids [21].


  1. Identification of PAHX, a Refsum disease gene. Mihalik, S.J., Morrell, J.C., Kim, D., Sacksteder, K.A., Watkins, P.A., Gould, S.J. Nat. Genet. (1997) [Pubmed]
  2. Identification of PEX7 as the second gene involved in Refsum disease. van den Brink, D.M., Brites, P., Haasjes, J., Wierzbicki, A.S., Mitchell, J., Lambert-Hamill, M., de Belleroche, J., Jansen, G.A., Waterham, H.R., Wanders, R.J. Am. J. Hum. Genet. (2003) [Pubmed]
  3. PTS2 protein import into mammalian peroxisomes. Legakis, J.E., Terlecky, S.R. Traffic (2001) [Pubmed]
  4. The human peroxisomal targeting signal receptor, Pex5p, is translocated into the peroxisomal matrix and recycled to the cytosol. Dammai, V., Subramani, S. Cell (2001) [Pubmed]
  5. Rhizomelic chondrodysplasia punctata is a peroxisomal protein targeting disease caused by a non-functional PTS2 receptor. Motley, A.M., Hettema, E.H., Hogenhout, E.M., Brites, P., ten Asbroek, A.L., Wijburg, F.A., Baas, F., Heijmans, H.S., Tabak, H.F., Wanders, R.J., Distel, B. Nat. Genet. (1997) [Pubmed]
  6. Human PEX7 encodes the peroxisomal PTS2 receptor and is responsible for rhizomelic chondrodysplasia punctata. Braverman, N., Steel, G., Obie, C., Moser, A., Moser, H., Gould, S.J., Valle, D. Nat. Genet. (1997) [Pubmed]
  7. PEX7 gene structure, alternative transcripts, and evidence for a founder haplotype for the frequent RCDP allele, L292ter. Braverman, N., Steel, G., Lin, P., Moser, A., Moser, H., Valle, D. Genomics (2000) [Pubmed]
  8. Mutation analysis of PEX7 in 60 probands with rhizomelic chondrodysplasia punctata and functional correlations of genotype with phenotype. Braverman, N., Chen, L., Lin, P., Obie, C., Steel, G., Douglas, P., Chakraborty, P.K., Clarke, J.T., Boneh, A., Moser, A., Moser, H., Valle, D. Hum. Mutat. (2002) [Pubmed]
  9. The mammalian peroxin Pex5pL, the longer isoform of the mobile peroxisome targeting signal (PTS) type 1 transporter, translocates the Pex7p.PTS2 protein complex into peroxisomes via its initial docking site, Pex14p. Otera, H., Harano, T., Honsho, M., Ghaedi, K., Mukai, S., Tanaka, A., Kawai, A., Shimizu, N., Fujiki, Y. J. Biol. Chem. (2000) [Pubmed]
  10. Molecular Mechanisms of Import of Peroxisome-targeting Signal Type 2 (PTS2) Proteins by PTS2 Receptor Pex7p and PTS1 Receptor Pex5pL. Mukai, S., Fujiki, Y. J. Biol. Chem. (2006) [Pubmed]
  11. A new family of Greek origin maps to the CRD locus for autosomal dominant cone-rod dystrophy on 19q. Papaioannou, M., Bessant, D., Payne, A., Bellingham, J., Rougas, C., Loutradis-Anagnostou, A., Gregory-Evans, C., Balassopoulou, A., Bhattacharya, S. J. Med. Genet. (1998) [Pubmed]
  12. Isolation of Chinese hamster ovary cell pex mutants: two PEX7-defective mutants. Yanago, E., Hiromasa, T., Matsumura, T., Kinoshita, N., Fujiki, Y. Biochem. Biophys. Res. Commun. (2002) [Pubmed]
  13. Functional studies on human Pex7p: subcellular localization and interaction with proteins containing a peroxisome-targeting signal type 2 and other peroxins. Ghys, K., Fransen, M., Mannaerts, G.P., Van Veldhoven, P.P. Biochem. J. (2002) [Pubmed]
  14. Involvement of Pex13p in Pex14p localization and peroxisomal targeting signal 2-dependent protein import into peroxisomes. Girzalsky, W., Rehling, P., Stein, K., Kipper, J., Blank, L., Kunau, W.H., Erdmann, R. J. Cell Biol. (1999) [Pubmed]
  15. Gas chromatography/mass spectrometry analysis of very long chain fatty acids, docosahexaenoic acid, phytanic acid and plasmalogen for the screening of peroxisomal disorders. Takemoto, Y., Suzuki, Y., Horibe, R., Shimozawa, N., Wanders, R.J., Kondo, N. Brain Dev. (2003) [Pubmed]
  16. Fatty alcohol accumulation in the autosomal recessive form of rhizomelic chondrodysplasia punctata. Rizzo, W.B., Craft, D.A., Judd, L.L., Moser, H.W., Moser, A.B. Biochem. Med. Metab. Biol. (1993) [Pubmed]
  17. Peroxisomal targeting signal receptor Pex5p interacts with cargoes and import machinery components in a spatiotemporally differentiated manner: conserved Pex5p WXXXF/Y motifs are critical for matrix protein import. Otera, H., Setoguchi, K., Hamasaki, M., Kumashiro, T., Shimizu, N., Fujiki, Y. Mol. Cell. Biol. (2002) [Pubmed]
  18. Disruption of the interaction of the longer isoform of Pex5p, Pex5pL, with Pex7p abolishes peroxisome targeting signal type 2 protein import in mammals. Study with a novel Pex5-impaired Chinese hamster ovary cell mutant. Matsumura, T., Otera, H., Fujiki, Y. J. Biol. Chem. (2000) [Pubmed]
  19. Molecular basis of Refsum disease: sequence variations in phytanoyl-CoA hydroxylase (PHYH) and the PTS2 receptor (PEX7). Jansen, G.A., Waterham, H.R., Wanders, R.J. Hum. Mutat. (2004) [Pubmed]
  20. Identification of a new complementation group of the peroxisome biogenesis disorders and PEX14 as the mutated gene. Shimozawa, N., Tsukamoto, T., Nagase, T., Takemoto, Y., Koyama, N., Suzuki, Y., Komori, M., Osumi, T., Jeannette, G., Wanders, R.J., Kondo, N. Hum. Mutat. (2004) [Pubmed]
  21. Rhizomelic chondrodysplasia punctata, a peroxisomal biogenesis disorder caused by defects in Pex7p, a peroxisomal protein import receptor: a minireview. Purdue, P.E., Skoneczny, M., Yang, X., Zhang, J.W., Lazarow, P.B. Neurochem. Res. (1999) [Pubmed]
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