title: Reevaluation of the role of Pex1 and dynamin-related proteins in peroxisome membrane biogenesis.
abstract: A recent model for peroxisome biogenesis postulates that peroxisomes form de novo continuously in wild-type cells by heterotypic fusion of endoplasmic reticulum-derived vesicles containing distinct sets of peroxisomal membrane proteins. This model proposes a role in vesicle fusion for the Pex1/Pex6 complex, which has an established role in matrix protein import. The growth and division model proposes that peroxisomes derive from existing peroxisomes. We tested these models by reexamining the role of Pex1/Pex6 and dynamin-related proteins in peroxisome biogenesis. We found that induced depletion of Pex1 blocks the import of matrix proteins but does not affect membrane protein delivery to peroxisomes; markers for the previously reported distinct vesicles colocalize in pex1 and pex6 cells; peroxisomes undergo continued growth if fission is blocked. Our data are compatible with the established primary role of the Pex1/Pex6 complex in matrix protein import and show that peroxisomes in Saccharomyces cerevisiae multiply mainly by growth and division.
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK.
authors.forename: Alison M
authors.initials: AM
authors.lastname: Motley
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Galvin
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK.
authors.forename: Lakhan
authors.initials: L
authors.lastname: Ekal
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK.
authors.forename: James M
authors.initials: JM
authors.lastname: Nuttall
authors.affiliation: Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, England, UK e.hettema@sheffield.ac.uk.
authors.forename: Ewald H
authors.initials: EH
authors.lastname: Hettema
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D034281:Dynamins / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009154:Mutation; D020675:Peroxisomes / Q000378:metabolism*; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D015398:Signal Transduction; D013347:Subcellular Fractions
chemical_list: D008565:Membrane Proteins; C491105:PEX13 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; D000251:Adenosine Triphosphatases; D000074183:ATPases Associated with Diverse Cellular Activities; C511586:PEX1 protein, S cerevisiae; C490760:PEX6 protein, S cerevisiae; D034281:Dynamins