Yeast peroxisomes multiply by growth and division.
Peroxisomes can arise de novo from the endoplasmic reticulum (ER) via a maturation process. Peroxisomes can also multiply by fission. We have investigated how these modes of multiplication contribute to peroxisome numbers in Saccharomyces cerevisiae and the role of the dynamin-related proteins (Drps) in these processes. We have developed pulse-chase and mating assays to follow the fate of existing peroxisomes, de novo-formed peroxisomes, and ER-derived preperoxisomal structures. We find that in wild-type (WT) cells, peroxisomes multiply by fission and do not form de novo. A marker for the maturation pathway, Pex3-GFP, is delivered from the ER to existing peroxisomes. Strikingly, cells lacking peroxisomes as a result of a segregation defect do form peroxisomes de novo. This process is slower than peroxisome multiplication in WT cells and is Drp independent. In contrast, peroxisome fission is Drp dependent. Our results show that peroxisomes multiply by growth and division under our assay conditions. We conclude that the ER to peroxisome pathway functions to supply existing peroxisomes with essential membrane constituents.
Motley
Alison M
AM
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, England, UK.
Hettema
Ewald H
EH
D034281:Dynamins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins; D000074401:Peroxins; D020675:Peroxisomes / Q000378:metabolism* / Q000648:ultrastructure; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins
D008565:Membrane Proteins; D024101:Mitochondrial Proteins; C070895:PEX3 protein, S cerevisiae; D000074401:Peroxins; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; C064553:VPS1 protein, S cerevisiae; C094774:DNM1 protein, S cerevisiae; D034281:Dynamins