Abstract
The spindle orientation checkpoint (SOC) in fission yeast has been proposed to delay metaphase-to-anaphase transition when the spindle poles are misaligned with respect to the long axis of the cell. This checkpoint is activated in the absence of either an actomyosin division ring or astral microtubules. Although the SOC could be overridden in the absence of the transcription factor Atf1p, its mechanistic nature remained unclear. Here, we show that the SOC-triggered metaphase delay depends on a subset of the spindle assembly checkpoint (SAC) components Mph1p and Bub1p. Based on this finding and a detailed imaging of the spindle orientation process, we hypothesized that the spindle pole might contain proteins capable of sensing the achievement of spindle alignment. We identified the kendrin-like spindle pole body resident Pcp1p as a candidate molecule. A targeted mutation in its central domain specifically triggered the SOC in spite of the presence of oriented spindles, causing a metaphase delay that could be relieved in the absence of Mph1p, Bub1p, and Atf1p. Thus, Pcp1p might provide a link between the mechanical process of spindle alignment and the signal transduction that initiates anaphase.
Original language | English |
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Pages (from-to) | 69-74 |
Number of pages | 6 |
Journal | Current biology : CB |
Volume | 14 |
Issue number | 1 |
DOIs | |
Publication status | Published - 6 Jan 2004 |
Keywords
- Cell Cycle
- Fluorescence
- Genes, cdc
- Nuclear Proteins
- Schizosaccharomyces
- Schizosaccharomyces pombe Proteins
- Signal Transduction
- Spindle Apparatus