Figure 3.
The HOG pathway promotes Cdc14 release from the nucleolus in MEN mutants treated with sorbitol. cdc15-2 (A1674) and cdc15-2 pbs2Δ (A10710) cells were arrested in G1 with α-factor and released from the block at 37°C. The percentage of cells with metaphfase and anaphase spindles (A–E) or Cdc14 release from the nucleolus in anaphase cells (H and I) was scored at the indicated times. Sorbitol (C, D, H, and I) or sorbitol and cycloheximide (1 mg/ml) (E) was added 120 min after release from the G1 arrest (0-time point, indicated by the orange arrow) with the exception of the control strains (A and B). Hyperosmotic stress stimulates the appearance of metaphase spindles (tubulin staining) in cdc15-2, but not in cdc15-2 pbs2Δ mutants (F) and release of Cdc14 from the nucleolus (G) at the restrictive temperature. Note that in contrast to anaphase spindles, metaphase spindles do not seem to be sensitive to sorbitol treatment. Spindle depolymerization upon sorbitol addition did not occur in cdc13-1 (A2598; our unpublished data).