title: Characterization of Schizosaccharomyces pombe copper transporter proteins in meiotic and sporulating cells.
abstract: Meiosis requires copper to undertake its program in which haploid gametes are produced from diploid precursor cells. In Schizosaccharomyces pombe, copper is transported by three members of the copper transporter (Ctr) family, namely Ctr4, Ctr5, and Ctr6. Although central for sexual differentiation, very little is known about the expression profile, cellular localization, and physiological contribution of the Ctr proteins during meiosis. Analysis of gene expression of ctr4(+) and ctr5(+) revealed that they are primarily expressed in early meiosis under low copper conditions. In the case of ctr6(+), its expression is broader, being detected throughout the entire meiotic process with an increase during middle- and late-phase meiosis. Whereas the expression of ctr4(+) and ctr5(+) is exclusively dependent on the presence of Cuf1, ctr6(+) gene expression relies on two distinct regulators, Cuf1 and Mei4. Ctr4 and Ctr5 proteins co-localize at the plasma membrane shortly after meiotic induction, whereas Ctr6 is located on the membrane of vacuoles. After meiotic divisions, Ctr4 and Ctr5 disappear from the cell surface, whereas Ctr6 undergoes an intracellular re-location to co-localize with the forespore membrane. Under copper-limiting conditions, disruption of ctr4(+) and ctr6(+) results in altered SOD1 activity, whereas these mutant cells exhibit substantially decreased levels of CAO activity mostly in early- and middle-phase meiosis. Collectively, these results emphasize the notion that Ctr proteins exhibit differential expression, localization, and contribution in delivering copper to SOD1 and Cao1 proteins during meiosis.
authors.affiliation: From the Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, Quebec J1E 4K8, Canada.
authors.forename: Samuel
authors.initials: S
authors.lastname: Plante
authors.forename: Raphaël
authors.initials: R
authors.lastname: Ioannoni
authors.forename: Jude
authors.initials: J
authors.lastname: Beaudoin
authors.forename: Simon
authors.initials: S
authors.lastname: Labbé
mesh_terms: D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000378:metabolism*; D007425:Intracellular Membranes / Q000378:metabolism*; D008540:Meiosis / Q000502:physiology*; D021381:Protein Transport / Q000502:physiology; D012568:Schizosaccharomyces / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism*
chemical_list: D027682:Cation Transport Proteins; C474030:Cuf1 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D014157:Transcription Factors; C489539:mei4 protein, S pombe; D003300:Copper; D013482:Superoxide Dismutase
keywords: Copper; Gene Regulation; Meiosis; Metalloproteins; Yeast