Abstract
In Saccharomyces cerevisiae, Ras proteins connect nutrient availability to cell growth through regulation of protein kinase A (PKA) activity. Ras proteins also have PKA-independent functions in mitosis and actin repolarization. We have found that mutations in MOB2 or CBK1 confer a slow-growth phenotype in a ras2Δ background. The slow-growth phenotype of mob2Δ ras2Δ cells results from a G1 delay that is accompanied by an increase in size, suggesting a G1/S role for Ras not previously described. In addition, mob2Δ strains have imprecise bud site selection, a defect exacerbated by deletion of RAS2. Mob2 and Cbk1 act to properly localize Ace2, a transcription factor that directs daughter cell-specific transcription of several genes. The growth and budding phenotypes of the double-deletion strains are Ace2 independent but are suppressed by overexpression of the PKA catalytic subunit, Tpk1. From these observations, we conclude that the PKA pathway and Mob2/ Cbk1 act in parallel to determine bud site selection and promote cell cycle progression.
Original language | English (US) |
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Pages (from-to) | 108-120 |
Number of pages | 13 |
Journal | Eukaryotic Cell |
Volume | 3 |
Issue number | 1 |
DOIs | |
State | Published - Feb 2004 |
All Science Journal Classification (ASJC) codes
- Microbiology
- Molecular Biology