title: Mps3p is a novel component of the yeast spindle pole body that interacts with the yeast centrin homologue Cdc31p.
abstract: Accurate duplication of the Saccharomyces cerevisiae spindle pole body (SPB) is required for formation of a bipolar mitotic spindle. We identified mutants in SPB assembly by screening a temperature-sensitive collection of yeast for defects in SPB incorporation of a fluorescently marked integral SPB component, Spc42p. One SPB assembly mutant contained a mutation in a previously uncharacterized open reading frame that we call MPS3 (for monopolar spindle). mps3-1 mutants arrest in mitosis with monopolar spindles at the nonpermissive temperature, suggesting a defect in SPB duplication. Execution point experiments revealed that MPS3 function is required for the first step of SPB duplication in G1. Like cells containing mutations in two other genes required for this step of SPB duplication (CDC31 and KAR1), mps3-1 mutants arrest with a single unduplicated SPB that lacks an associated half-bridge. MPS3 encodes an essential integral membrane protein that localizes to the SPB half-bridge. Genetic interactions between MPS3 and CDC31 and binding of Cdc31p to Mps3p in vitro, as well as the fact that Cdc31p localization to the SPB is partially dependent on Mps3p function, suggest that one function for Mps3p during SPB duplication is to recruit Cdc31p, the yeast centrin homologue, to the half-bridge.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
authors.forename: Sue L
authors.initials: SL
authors.lastname: Jaspersen
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Giddings
authors.forename: Mark
authors.initials: M
authors.lastname: Winey
mesh_terms: D020816:Amino Acid Motifs; D015153:Blotting, Western; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008938:Mitosis; D008954:Models, Biological; D009154:Mutation; D009687:Nuclear Proteins; D010641:Phenotype; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008941:Spindle Apparatus / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors
chemical_list: C083769:CDC31 protein, S cerevisiae; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D008164:Luminescent Proteins; D008565:Membrane Proteins; C471174:Mps3 protein, S cerevisiae; D009687:Nuclear Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins