Bub1 is a fission yeast kinetochore scaffold protein, and is sufficient to recruit other spindle checkpoint proteins to ectopic sites on chromosomes

PLoS One. 2007 Dec 19;2(12):e1342. doi: 10.1371/journal.pone.0001342.

Abstract

The spindle checkpoint delays anaphase onset until all chromosomes have attached in a bi-polar manner to the mitotic spindle. Mad and Bub proteins are recruited to unattached kinetochores, and generate diffusible anaphase inhibitors. Checkpoint models propose that Mad1 and Bub1 act as stable kinetochore-bound scaffolds, to enhance recruitment of Mad2 and Mad3/BubR1, but this remains untested for Bub1. Here, fission yeast FRAP experiments confirm that Bub1 stably binds kinetochores, and by tethering Bub1 to telomeres we demonstrate that it is sufficient to recruit anaphase inhibitors in a kinase-independent manner. We propose that the major checkpoint role for Bub1 is as a signalling scaffold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Chromosomes, Fungal*
  • DNA Primers
  • Kinetochores / metabolism*
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Serine-Threonine Kinases / physiology*
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / metabolism
  • Schizosaccharomyces pombe Proteins / physiology*
  • Signal Transduction
  • Spindle Apparatus / metabolism*

Substances

  • DNA Primers
  • Schizosaccharomyces pombe Proteins
  • Bub1 protein, S pombe
  • Protein Serine-Threonine Kinases