The Bub2p spindle checkpoint links nuclear migration with mitotic exit

Mol Cell. 2000 Jul;6(1):1-10.


Bfa1p and Bub2p are spindle checkpoint proteins that likely have GTPase activation activity and are associated with the budding yeast spindle pole body (SPB). Here, we show that Bfa1p and Bub2p bind the Ras-like GTPase Tem1p, a component of the mitotic exit network, to the cytoplasmic face of the SPB that enters the bud, whereas the GDP/GTP exchange factor Lte1p is associated with the cortex of the bud. Migration of the SPB into the bud probably allows activation of Tem1p through Lte1p, thereby linking nuclear migration with mitotic exit. Since components of the Bub2p checkpoint are conserved in other organisms, we propose that the position of the SPB or mammalian centrosome controls the timing of mitotic exit.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle
  • Cell Cycle Proteins*
  • Cell Nucleus / metabolism
  • Cytoskeletal Proteins*
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Guanine Nucleotide Exchange Factors*
  • Microscopy, Immunoelectron
  • Microtubules / metabolism
  • Mitosis
  • Monomeric GTP-Binding Proteins / genetics
  • Monomeric GTP-Binding Proteins / metabolism
  • Movement
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins*
  • Sister Chromatid Exchange
  • Spindle Apparatus / metabolism*


  • BFA1 protein, S cerevisiae
  • BUB2 protein, S cerevisiae
  • Cell Cycle Proteins
  • Cytoskeletal Proteins
  • Fungal Proteins
  • Guanine Nucleotide Exchange Factors
  • LTE1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • TEM1 protein, S cerevisiae
  • Monomeric GTP-Binding Proteins