Evolving increased caffeine tolerance in yeast can help us understand challenges in industrial processes and study basic biological pathways. Learn about evolving caffeine tolerance at home through our paper in microPublication Biology and a feature on it from the podcast This Week in Microbiology!
S. cerevisiae is used in the production and processing of coffee and chocolate, both of which contain caffeine. The concentrations of caffeine we use for our yEvo experimental evolution procedures are comparable to foods we consume: espresso contains approximately 11mM caffeine, which is slightly higher than the starting concentration of caffeine for our evolution experiments. By studying how yeast adapts to increased concentrations of caffeine, we investigate processes that may occur naturally in yeast used to make products of caffeinated foods.
Caffeine is also useful as a tool, because it inhibits the protein TOR. TOR is a master regulator of many cellular porcesses including growth, nutrient response, and aging. Drugs that inhibit the mammalian TOR protein are used to treat autoimmune disorders and investigated for cancer therapy. By investigating what proteins and cellular processes are altered in our yeast with increased caffeine tolerance, we aim to increase our knowledge of the regulation of TOR signaling, and parallel pathways that can compensate for its inhibition.
This project is being carried out with Rebecca Brewer at Troy High School, Tim Renz at Tukwila High School, and Ryan Skophammer at Westridge School. The evolutions have been completed, and further studies are underway with Bryce Taylor at Loras College and Maitreya Dunham at the University of Washington!