Single-cell imaging reveals a key role of Bck2 in yeast cell size adaptation to nutrient challenges.

Bck2 is essential for yeast cell size adaptation during nutrient shifts, with bck2Δ cells showing longer cell cycle arrests and increased enlargement compared to wild-type.

• Why it matters: Understanding cell size regulation under changing environmental conditions is crucial because steady-state studies may mask unique roles of regulators like Bck2 during nutrient transitions, impacting cell function and survival.
• What they did: The researchers used live-cell microscopy and machine learning-assisted image analysis to track single yeast cells and their progeny through a switch from fermentable to nonfermentable media, comparing wild-type and mutant strains.
• The result: Findings reveal that Bck2 becomes the key G1/S activator during nutrient changes, and its absence leads to prolonged arrests and abnormal cell enlargement, highlighting its specific role in size adaptation.