Volume 581, Issue 15, 19 June 2007, Pages 2811–2819
Vienna Special Issue: Molecular Machines
The peroxisomal protein import machinery
Edited by Horst Feldmann
Harald W. Platta, Ralf Erdmann
Abteilung für Systembiochemie, Medizinische Fakultät der Ruhr-Universität Bochum, D-44780 Bochum, Germany
Received 2 March 2007, Revised 27 March 2007, Accepted 2 April 2007, Available online 9 April 2007
Under an Elsevier user license
Peroxisomal matrix protein import cascade. The peroxisomal protein import conceptually can be divided in four steps: (i) cargo recognition in the cytosol and direction of the receptor–cargo complexes to the peroxisomal membrane. (ii) Translocation of the receptor–cargo complex to the luminal site of the peroxisomal membrane. (iii) Disassembly of the receptor–cargo complex in the peroxisomal lumen and (iv) return of the receptor to the cytosol.
Peroxisomes are unique organelles whose physiological functions vary depending on the cellular environment or metabolic and developmental state of the organism. These changes in enzyme content are accomplished by the dynamically operating membrane and matrix protein import machineries of peroxisomes that rely on the concerted function of at least 20 peroxins. The import of folded matrix proteins is mediated by cycling receptors that shuttle between the cytosol and peroxisomal lumen. Receptor release back to the cytosol represents the ATP-dependent step of peroxisomal matrix protein import, which consists of two energy-consuming reactions: receptor ubiquitination and dislocation.
AAA, ATPase associated with various cellular activities; ERAD, endoplasmatic reticulum associated degradation; PTS, peroxisomal targeting signal; RING, really interesting new gene; Ub, ubiquitin
Peroxisome biogenesis; Protein targeting; PEX; Peroxin; Ubiquitination; AAA ATPases
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