Structural highlights
Function
[PEX7_YEAST] Binds to the N-terminal PTS2-type peroxisomal targeting signal and plays an essential role in peroxisomal protein import essential for import of 3-oxoacyl-CoA thiolase (a PTS2-containing protein) into peroxisomes. May direct thiolase to peroxisomes by shuttling between the cytosol and peroxisomal membranes. [PEX21_YEAST] Involved in peroxisome biogenesis and the import of peroxisomal matrix proteins that contain the peroxisomal targeting sequence PTS2. Required for peroxisomal targeting of PEX7 and growth on oleate. Acts as an activator of the seryl-tRNA synthetase SES1 by increasing its binding to tRNA.[1] [2] [3] [4]
Publication Abstract from PubMed
Appropriate targeting of matrix proteins to peroxisomes is mainly directed by two types of peroxisomal targeting signals, PTS1 and PTS2. Although the basis of PTS1 recognition has been revealed by structural studies, that of PTS2 recognition remains elusive. Here we present the crystal structure of a heterotrimeric PTS2-recognition complex from Saccharomyces cerevisiae, containing Pex7p, the C-terminal region of Pex21p and the PTS2 of the peroxisomal 3-ketoacyl-CoA thiolase. Pex7p forms a beta-propeller structure and provides a platform for cooperative interactions with both the amphipathic PTS2 helix and Pex21p. The C-terminal region of Pex21p directly covers the hydrophobic surfaces of both Pex7p and PTS2, and the resulting hydrophobic core is the primary determinant of stable complex formation. Together with in vivo and in vitro functional assays of Pex7p and Pex21p variants, our findings reveal the molecular mechanism of PTS2 recognition.
Crystal structure of peroxisomal targeting signal-2 bound to its receptor complex Pex7p-Pex21p.,Pan D, Nakatsu T, Kato H Nat Struct Mol Biol. 2013 Aug;20(8):987-93. doi: 10.1038/nsmb.2618. Epub 2013 Jun, 30. PMID:23812376[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Purdue PE, Yang X, Lazarow PB. Pex18p and Pex21p, a novel pair of related peroxins essential for peroxisomal targeting by the PTS2 pathway. J Cell Biol. 1998 Dec 28;143(7):1859-69. PMID:9864360
- ↑ Rocak S, Landeka I, Weygand-Durasevic I. Identifying Pex21p as a protein that specifically interacts with yeast seryl-tRNA synthetase. FEMS Microbiol Lett. 2002 Aug 27;214(1):101-6. PMID:12204379
- ↑ Stein K, Schell-Steven A, Erdmann R, Rottensteiner H. Interactions of Pex7p and Pex18p/Pex21p with the peroxisomal docking machinery: implications for the first steps in PTS2 protein import. Mol Cell Biol. 2002 Sep;22(17):6056-69. PMID:12167700
- ↑ Godinic V, Mocibob M, Rocak S, Ibba M, Weygand-Durasevic I. Peroxin Pex21p interacts with the C-terminal noncatalytic domain of yeast seryl-tRNA synthetase and forms a specific ternary complex with tRNA(Ser). FEBS J. 2007 Jun;274(11):2788-99. Epub 2007 Apr 20. PMID:17451428 doi:10.1111/j.1742-4658.2007.05812.x
- ↑ Pan D, Nakatsu T, Kato H. Crystal structure of peroxisomal targeting signal-2 bound to its receptor complex Pex7p-Pex21p. Nat Struct Mol Biol. 2013 Aug;20(8):987-93. doi: 10.1038/nsmb.2618. Epub 2013 Jun, 30. PMID:23812376 doi:http://dx.doi.org/10.1038/nsmb.2618
