Cell cycle-dependent control of fatty acid biosynthesis in budding yeast
Cells are the building blocks of all life. To grow and divide, cells must produce the right materials at the right time — much like a factory that needs to coordinate its production process with precise timing. Baker's yeast is a widely used model organism in biology. In this fungus, the production of fats, essential for the cell membrane, is known to occur at specific moments during the cell cycle. However, how the cell controls this schedule of fat production was largely unknown. In this thesis, we investigate how the cell regulates fat production over time and what happens when this process is disrupted.To remove proteins from the cell in a controlled manner, we first tested and improved a molecular tool known as the AID2 system.
We discovered that this system sometimes degrades proteins unintentionally, which can lead to misleading results in sensitive experiments.Using this improved tool, we studied the enzyme Acc1, which carries out the first step of fat synthesis.
We show that the cell actively regulates the amount of Acc1 throughout the cell cycle through both production and degradation. When we disrupted this regulation, cells produced too much fat, leading to lethal damage to the cell membrane — evidence that the timing of fat production is essential for survival.
Finally, we investigated whether intermediates of fat synthesis also control other processes in the cell. Although we found indications of such connections, it proved difficult to distinguish these from a general stress response that occurs when fat production is shut down.