title: Preperoxisomal vesicles can form in the absence of Pex3.
abstract: We demonstrate that the peroxin Pex3 is not required for the formation of peroxisomal membrane structures in yeast pex3 mutant cells. Notably, pex3 mutant cells already contain reticular and vesicular structures that harbor key proteins of the peroxisomal receptor docking complex-Pex13 and Pex14-as well as the matrix proteins Pex8 and alcohol oxidase. Other peroxisomal membrane proteins in these cells are unstable and transiently localized to the cytosol (Pex10, Pmp47) or endoplasmic reticulum (Pex11). These reticular and vesicular structures are more abundant in cells of a pex3 atg1 double deletion strain, as the absence of Pex3 may render them susceptible to autophagic degradation, which is blocked in this double mutant. Contrary to earlier suggestions, peroxisomes are not formed de novo from the endoplasmic reticulum when the PEX3 gene is reintroduced in pex3 cells. Instead, we find that reintroduced Pex3 sorts to the preperoxisomal structures in pex3 cells, after which these structures mature into normal peroxisomes.
authors.affiliation: Molecular Cell Biology, University of Groningen, 9747 AG Groningen, Netherlands.
authors.forename: Kèvin
authors.initials: K
authors.lastname: Knoops
authors.forename: Selvambigai
authors.initials: S
authors.lastname: Manivannan
authors.forename: Malgorzata N
authors.initials: MN
authors.lastname: Cepinska
authors.forename: Arjen M
authors.initials: AM
authors.lastname: Krikken
authors.forename: Anita M
authors.initials: AM
authors.lastname: Kram
authors.forename: Marten
authors.initials: M
authors.lastname: Veenhuis
authors.forename: Ida J
authors.initials: IJ
authors.lastname: van der Klei
mesh_terms: D001343:Autophagy; D005656:Fungal Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000032:analysis; D007425:Intracellular Membranes / Q000378:metabolism / Q000648:ultrastructure; D008565:Membrane Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D020675:Peroxisomes / Q000378:metabolism* / Q000648:ultrastructure; D010843:Pichia / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics
chemical_list: D005656:Fungal Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D049452:Green Fluorescent Proteins; D044767:Ubiquitin-Protein Ligases