Mitotic cyclin Clb4 is required for the intracellular adaptation to glucose starvation in Saccharomyces cerevisiae

Cellular homeostasis in response to glucose availability is maintained through the tight coordination of various physiological processes, including cell proliferation, transcription, and metabolism. In this study, we use the budding yeast Saccharomyces cerevisiae to identify proteins implicated in carbon source-dependent modulation of physiological processes. We find that the mitotic cyclin Clb4 is required for optimal regulation of glucose-starvation-responsive pathways through the target of rapamycin complex 1. Cells lacking Clb4 are characterized by dysregulation of autophagy and impaired modulation of cell size. Notably, cell viability after prolonged glucose starvation is severely reduced by disruption of Clb4. We conclude that Clb4, in addition to its function in the cell cycle, plays a role in the intracellular adaptation to glucose starvation.