Title: The peroxisomal protein import machinery displays a preference for monomeric substrates
Authors: Freitas, Marta O
Francisco, Tânia
Rodrigues, Tony A
Lismont, Celien
Domingues, Pedro
Pinto, Manuel P
Grou, Cláudia P
Fransen, Marc
Azevedo, Jorge E # ×
Issue Date: 8-Apr-2015
Publisher: The Royal Society Publishing
Series Title: Open Biology vol:5 issue:4
Article number: 10.1098/rsob.140236
Abstract: Peroxisomal matrix proteins are synthesized on cytosolic ribosomes and transported by the shuttling receptor PEX5 to the peroxisomal membrane docking/translocation machinery, where they are translocated into the organelle matrix. Under certain experimental conditions this protein import machinery has the remarkable capacity to accept already oligomerized proteins, a property that has heavily influenced current models on the mechanism of peroxisomal protein import. However, whether or not oligomeric proteins are really the best and most frequent clients of this machinery remain unclear. In this work, we present three lines of evidence suggesting that the peroxisomal import machinery displays a preference for monomeric proteins. First, in agreement with previous findings on catalase, we show that PEX5 binds newly synthesized (monomeric) acyl-CoA oxidase 1 (ACOX1) and urate oxidase (UOX), potently inhibiting their oligomerization. Second, in vitro import experiments suggest that monomeric ACOX1 and UOX are better peroxisomal import substrates than the corresponding oligomeric forms. Finally, we provide data strongly suggesting that although ACOX1 lacking a peroxisomal targeting signal can be imported into peroxisomes when co-expressed with ACOX1 containing its targeting signal, this import pathway is inefficient.
ISSN: 2046-2441
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Laboratory of Lipid Biochemistry and Protein Interactions
× corresponding author
# (joint) last author

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