title: Pexophagy-linked degradation of the peroxisomal membrane protein Pex3p involves the ubiquitin-proteasome system.
abstract: Peroxisome autophagy, also known as pexophagy, describes the wholesale degradation of peroxisomes via the vacuole, when organelles become damaged or redundant. In the methylotrophic yeast Hansenula polymorpha, pexophagy is stimulated when cells growing on methanol are exposed to excess glucose. Degradation of the peroxisomal membrane protein Pex3p, a process that does not involve the vacuole, was shown to trigger pexophagy. In this contribution, we have characterised pexophagy-associated Pex3p degradation further. We show that Pex3p breakdown depends on ubiquitin and confirm that Pex3p is a target for ubiquitination. Furthermore, we identify a role for the peroxisomal E3 ligases Pex2p and Pex10p in Pex3p degradation, suggesting the existence of a ubiquitin-dependent pathway involved in removing proteins from the peroxisomal membrane.
authors.affiliation: Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, The Netherlands. c.p.williams@rug.nl
authors.forename: Chris
authors.initials: C
authors.lastname: Williams
authors.forename: Ida J
authors.initials: IJ
authors.lastname: van der Klei
mesh_terms: D001343:Autophagy; D001692:Biological Transport; D004721:Endoplasmic Reticulum / Q000378:metabolism; D005656:Fungal Proteins / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D020675:Peroxisomes / Q000378:metabolism*; D010843:Pichia / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D025801:Ubiquitin; D049452:Green Fluorescent Proteins; D046988:Proteasome Endopeptidase Complex
keywords: Autophagy; Hansenula polymorpha; Peroxisome; Pex10p; Pex2p; Pex3p; Pexophagy; Proteasome; Protein degradation; Ubiquitination