Modes of spindle pole body inheritance and segregation of the Bfa1p–Bub2p checkpoint protein complex

AUTOR(ES)

Pereira, Gislene

FONTE

Oxford University Press

RESUMO

Yeast spindle pole bodies (SPBs) duplicate once per cell cycle by a conservative mechanism resulting in a pre-existing ‘old’ and a newly formed SPB. The two SPBs of yeast cells are functionally distinct. It is only the SPB that migrates into the daughter cell, the bud, which carries the Bfa1p–Bub2p GTPase-activating protein (GAP) complex, a component of the spindle positioning checkpoint. We investigated whether the functional difference of the two SPBs correlates with the time of their assembly. We describe that in unperturbed cells the ‘old’ SPB always migrates into the bud. However, Bfa1p localization is not determined by SPB inheritance. It is the differential interaction of cytoplasmic microtubules with the mother and bud cortex that directs the Bfa1p–Bub2p GAP to the bud-ward-localized SPB. In response to defects of cytoplasmic microtubules to interact with the cell cortex, the Bfa1p–Bub2p complex binds to both SPBs. This may provide a mechanism to delay cell cycle progression when cytoplasmic microtubules fail to orient the spindle. Thus, SPBs are able to sense cytoplasmic microtubule properties and regulate the Bfa1p–Bub2p GAP accordingly.

Documentos Relacionados

• Function of Cdc2p-dependent Bub1p phosphorylation and Bub1p kinase activity in the mitotic and meiotic spindle checkpoint
• Bub1p Kinase Activates the Saccharomyces cerevisiae Spindle Assembly Checkpoint
• Kinetochore Targeting of Fission Yeast Mad and Bub Proteins Is Essential for Spindle Checkpoint Function but Not for All Chromosome Segregation Roles of Bub1p†
• Simian virus 40 large T antigen targets the spindle assembly checkpoint protein Bub1
• Phosphorylation and activation of Bub1 on unattached chromosomes facilitate the spindle checkpoint