Peroxisomal proteostasis involves a Lon family protein that functions as protease and chaperone.
Proteins are subject to continuous quality control for optimal proteostasis. The knowledge of peroxisome quality control systems is still in its infancy. Here we show that peroxisomes contain a member of the Lon family of proteases (Pln). We show that Pln is a heptameric protein and acts as an ATP-fueled protease and chaperone. Hence, Pln is the first chaperone identified in fungal peroxisomes. In cells of a PLN deletion strain peroxisomes contain protein aggregates, a major component of which is catalase-peroxidase. We show that this enzyme is sensitive to oxidative damage. The oxidatively damaged, but not the native protein, is a substrate of the Pln protease. Cells of the pln strain contain enhanced levels of catalase-peroxidase protein but reduced catalase-peroxidase enzyme activities. Together with the observation that Pln has chaperone activity in vitro, our data suggest that catalase-peroxidase aggregates accumulate in peroxisomes of pln cells due to the combined absence of Pln protease and chaperone activities.
Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, Kluyver Centre for Genomics of Industrial Fermentation, P. O. Box 11103, 9700CC Groningen, The Netherlands.
Magdalena
M
Bartoszewska
Chris
C
Williams
Alexey
A
Kikhney
Łukasz
Ł
Opaliński
Carlo W T
CW
van Roermund
Rinse
R
de Boer
Marten
M
Veenhuis
Ida J
IJ
van der Klei
D057065:ATP-Dependent Endopeptidases / Q000235:genetics / Q000378:metabolism*; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology; D010408:Penicillium chrysogenum / Q000201:enzymology* / Q000235:genetics; D020675:Peroxisomes / Q000201:enzymology* / Q000235:genetics
D057065:ATP-Dependent Endopeptidases; D005656:Fungal Proteins; D018832:Molecular Chaperones; D002374:Catalase