Regulation of Saccharomyces cerevisiae kinetochores by the type 1 phosphatase Glc7p

Ingrid Sassoon, Fedor F Severin, Paul D Andrews, Maria-Rita Taba, Ken B Kaplan, Anthony J Ashford, Michael J R Stark, Peter K Sorger, Anthony A Hyman

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    Abstract

    We have investigated the role of protein phosphorylation in regulation of Saccharomyces cerevisiae kinetochores. By use of phosphatase inhibitors and a type 1 protein phosphatase mutant (glc7-10), we show that the microtubule binding activity, but not the centromeric DNA-binding activity, of the kinetochore complex is regulated by a balance between a protein kinase and the type 1 protein phosphatase (PP1) encoded by the GLC7 gene. glc7-10 mutant cells exhibit low kinetochore-microtubule binding activity in vitro and a high frequency of chromosome loss in vivo. Specifically, the Ndc10p component of the centromere DNA-binding CBP3 complex is altered by the glc7-10 mutation; Ndc10p is hyperphosphorylated in glc7-10 extracts. Furthermore, addition of recombinant Ndc10p reconstitutes the microtubule-binding activity of a glc7-10 extract to wild-type levels. Finally, the glc7-10-induced mitotic arrest is abolished in spindle checkpoint mutants, suggesting that defects in kinetochore-microtubule interactions caused by hyperphosphorylation of kinetochore proteins activate the spindle checkpoint.

    Original languageEnglish
    Pages (from-to)545-555
    Number of pages11
    JournalGenes & Development
    Volume13
    Issue number5
    Publication statusPublished - 1999

    Cite this

    Sassoon, I., Severin, F. F., Andrews, P. D., Taba, M-R., Kaplan, K. B., Ashford, A. J., Stark, M. J. R., Sorger, P. K., & Hyman, A. A. (1999). Regulation of Saccharomyces cerevisiae kinetochores by the type 1 phosphatase Glc7p. Genes & Development, 13(5), 545-555. http://genesdev.cshlp.org/content/13/5/545.full