Quantitative proteomic analysis of purified yeast kinetochores identifies a PP1 regulatory subunit

Bungo Akiyoshi, Christian R. Nelson, Jeffrey A. Ranish, Sue Biggins*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

The kinetochore is a macromolecular complex that controls chromosome segregation and cell cycle progression. When sister kinetochores make bioriented attachments to microtubules from opposite poles, the spindle checkpoint is silenced. Biorientation and the spindle checkpoint are regulated by a balance between the Ipl1/ Aurora B protein kinase and the opposing activity of protein phosphatase I (PP1). However, little is known about the regulation of PP1 localization and activity at the kinetochore. Here, we developed a method to purify centromere-bound kinetochores and used quantitative proteomics to identify the Fin1 protein as a PP1 regulatory subunit. The Fin1/PP1 complex is regulated by phosphorylation and 14-3-3 protein binding. When Fin1 is mislocalized, bipolar spindles fail to assemble but the spindle checkpoint is inappropriately silenced due to PP1 activity. These data suggest that Fin1 is a PP1 regulatory subunit whose spatial and temporal activity must be precisely controlled to ensure genomic stability.

Original languageEnglish
Pages (from-to)2887-2899
Number of pages13
JournalGenes and Development
Issue number24
Publication statusPublished - 15 Dec 2009
Externally publishedYes

Keywords / Materials (for Non-textual outputs)

  • Kinetochore
  • Ipl1/Aurora B protein kinase
  • PP1/Glc7 protein phosphatase I
  • Fin1
  • 14-3-3
  • SILAC quantitative mass spectrometry


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