Regulation of Cell Cycle Progression by Swe1p and Hog1p Following Hypertonic Stress
- 1 January 2001
- journal article
- Published by American Society for Cell Biology (ASCB) in Molecular Biology of the Cell
- Vol. 12 (1), 53-62
- https://doi.org/10.1091/mbc.12.1.53
Abstract
Exposure of yeast cells to an increase in external osmolarity induces a temporary growth arrest. Recovery from this stress is mediated by the accumulation of intracellular glycerol and the transcription of several stress response genes. Increased external osmolarity causes a transient accumulation of 1N and 2N cells and a concomitant depletion of S phase cells. Hypertonic stress triggers a cell cycle delay in G2 phase cells that appears distinct from the morphogenesis checkpoint, which operates in early S phase cells. Hypertonic stress causes a decrease in CLB2 mRNA, phosphorylation of Cdc28p, and inhibition of Clb2p-Cdc28p kinase activity, whereas Clb2 protein levels are unaffected. Like the morphogenesis checkpoint, the osmotic stress-induced G2 delay is dependent upon the kinase Swe1p, but is not tightly correlated with inhibition of Clb2p-Cdc28p kinase activity. Thus, deletion ofSWE1 does not prevent the hypertonic stress-induced inhibition of Clb2p-Cdc28p kinase activity. Mutation of the Swe1p phosphorylation site on Cdc28p (Y19) does not fully eliminate the Swe1p-dependent cell cycle delay, suggesting that Swe1p may have functions independent of Cdc28p phosphorylation. Conversely, deletion of the mitogen-activated protein kinase HOG1 does prevent Clb2p-Cdc28p inhibition by hypertonic stress, but does not block Cdc28p phosphorylation or alleviate the cell cycle delay. However, Hog1p does contribute to proper nuclear segregation after hypertonic stress in cells that lack Swe1p. These results suggest a hypertonic stress-induced cell cycle delay in G2 phase that is mediated in a novel way by Swe1p in cooperation with Hog1p.Keywords
This publication has 45 references indexed in Scilit:
- A Morphogenesis Checkpoint Monitors the Actin Cytoskeleton in YeastThe Journal of cell biology, 1998
- Cdc2 tyrosine phosphorylation is required for the DNA damage checkpoint in fission yeast.Genes & Development, 1997
- The spindle assembly checkpointCurrent Opinion in Cell Biology, 1996
- Transcriptional Remodeling and G1 Arrest in Dioxygen Stress in Saccharomyces cerevisiaePublished by Elsevier BV ,1996
- Cell-cycle control linked to extracellular environment by MAP kinase pathway in fission yeastNature, 1995
- Direct Inhibition of the Yeast Cyclin-Dependent Kinase Cdc28-Cln by Far1Science, 1994
- Mitotic checkpoint genes in budding yeast and the dependence of mitosis on DNA replication and repair.Genes & Development, 1994
- An Osmosensing Signal Transduction Pathway in YeastScience, 1993
- Tyrosine phosphorylation of the fission yeast cdc2+ protein kinase regulates entry into mitosisNature, 1989
- cdc25+ functions as an inducer in the mitotic control of fission yeastCell, 1986