Peroxin-7
| Peroxin-7 | ||
|---|---|---|
| Properties of human protein | ||
| Mass / length primary structure | 323 amino acids | |
| Cofactor | Pex5 | |
| Identifier | ||
| Gene name | PEX7 | |
| External IDs | ||
| Transporter classification | ||
| TCDB | 3.A.20.1.1 | |
| designation | Peroxisomal importer | |
| Occurrence | ||
| Homology family | PTS2 transporter | |
| Parent taxon | Eukaryotes | |
Peroxin-7 (synonyms: PTS2 transporter, Pex7p) is a transport protein that transports certain other proteins that are used in peroxisomes or glyoxisomes (in plants) from the cytoplasm into these organelles. Pex7p recognizes such proteins to be transported after they have been translated in the endoplasmic reticulum by an amino acid sequence , the PTS2 signal. Pex7p is part of a protein complex that consists of several sub- complexes , and there are at least four transport routes into the organelles. Peroxin-7 is found in all eukaryotes and in humans in all tissue types, especially in the pancreas , skeletal muscles and heart .
The enzymes transported by Peroxin-7 include phytanoyl-CoA hydroxylase , the defect of which is the cause of Refsum's syndrome , and alkyl dihydroxyacetone phosphate synthetase , which catalyzes the first step in the biosynthesis of ether phospholipids and thus the synthesis of plasmalogens , as well as peroxisomal thiolase 1, responsible for the last step in the β-oxidation of long- chain fatty acids .
PTS2-containing proteins are bound by Pex7p, which is mostly present as a monomer in the cytoplasm , where it binds to the newly synthesized PTS2-labeled proteins and is imported into the peroxisome together with them. Pex7p then recycles into the cytoplasm.
The gene locus for the PEX7 gene is 6q21-22.2. Defects in this gene trigger either rhizomelic chondrodysplasia punctata type 1 (RCDP1, MIM # 215100) or Refsum's syndrome , depending on the residual activity of the resulting protein .