Nutrient signaling and cell cycle control

The survival and development of all organisms depends on their ability to regulate cell growth and cell proliferation in response to external stimuli such as growth factors and nutrients. However, the connection between pathways promoting growth and the cell cycle machinery is still poorly understood. In budding yeast, cell growth and proliferation depends exclusively on the presence of nutrients in the medium and therefore provides an excellent model system to study how eukaryotic cells regulate their cell cycle in response to external factors. Using a collection of mutants defective in cell survival after a prolonged starvation period, I started to identify genes required for cell cycle arrest upon nutrient withdrawal. Interestingly, I have found that some mutants defective in targeting proteins to the vacuole are unable to arrest the cell cycle under nutrient limiting conditions. In a second approach, I hope to identify negative regulators of the starvation response that when mutated activate the starvation response even under nutrient rich conditions. Taken together, these experiments should contribute to a more complete understanding of growth and cell cycle control, which ultimately is of great interest for understanding development and disease.