title: A role for Vps1p, actin, and the Myo2p motor in peroxisome abundance and inheritance in Saccharomyces cerevisiae.
abstract: In vivo time-lapse microscopy reveals that the number of peroxisomes in Saccharomyces cerevisiae cells is fairly constant and that a subset of the organelles are targeted and segregated to the bud in a highly ordered, vectorial process. The dynamin-like protein Vps1p controls the number of peroxisomes, since in a vps1Delta mutant only one or two giant peroxisomes remain. Analogous to the function of other dynamin-related proteins, Vps1p may be involved in a membrane fission event that is required for the regulation of peroxisome abundance. We found that efficient segregation of peroxisomes from mother to bud is dependent on the actin cytoskeleton, and active movement of peroxisomes along actin filaments is driven by the class V myosin motor protein, Myo2p: (a) peroxisomal dynamics always paralleled the polarity of the actin cytoskeleton, (b) double labeling of peroxisomes and actin cables revealed a close association between both, (c) depolymerization of the actin cytoskeleton abolished all peroxisomal movements, and (d) in cells containing thermosensitive alleles of MYO2, all peroxisome movement immediately stopped at the nonpermissive temperature. In addition, time-lapse videos showing peroxisome movement in wild-type and vps1Delta cells suggest the existence of various levels of control involved in the partitioning of peroxisomes.
authors.affiliation: Lehrstuhl für Angewandte Mikrobiologie, Biozentrum, Universität Basel, CH-4056 Basel, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Hoepfner
authors.forename: M
authors.initials: M
authors.lastname: van den Berg
authors.forename: P
authors.initials: P
authors.lastname: Philippsen
authors.forename: H F
authors.initials: HF
authors.lastname: Tabak
authors.forename: E H
authors.initials: EH
authors.lastname: Hettema
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D019204:GTP-Binding Proteins; D017353:Gene Deletion; D049452:Green Fluorescent Proteins; D007202:Indicators and Reagents / Q000378:metabolism; D008164:Luminescent Proteins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D008869:Microtubule-Associated Proteins / Q000235:genetics; D008870:Microtubules; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D018995:Myosin Heavy Chains / Q000378:metabolism*; D024701:Myosin Type V / Q000378:metabolism*; D015345:Oligonucleotide Probes; D000074435:Peroxisome-Targeting Signal 1 Receptor; D020675:Peroxisomes / Q000378:metabolism*; D011108:Polymers / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D033921:Vesicular Transport Proteins
chemical_list: D000199:Actins; D001426:Bacterial Proteins; C090135:Cap2 protein, S cerevisiae; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D007202:Indicators and Reagents; D008164:Luminescent Proteins; C077512:MYO2 protein, S cerevisiae; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins; D015345:Oligonucleotide Probes; D000074435:Peroxisome-Targeting Signal 1 Receptor; D011108:Polymers; D018160:Receptors, Cytoplasmic and Nuclear; C418484:SPC72 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; C054562:yellow fluorescent protein, Bacteria; D049452:Green Fluorescent Proteins; D019204:GTP-Binding Proteins; D024701:Myosin Type V; C064553:VPS1 protein, S cerevisiae; D018995:Myosin Heavy Chains