Systematic identification of cell size regulators in budding yeast

Area of Science:

• Cell Biology
• Genetics
• Molecular Biology

Background:

• Cell size is a fundamental biological parameter crucial for cellular function.
• Cell size is tightly regulated by the coordinated processes of cell growth and division.
• Understanding cell size control mechanisms is vital for comprehending cellular homeostasis and development.

Purpose of the Study:

• To systematically identify genes and pathways regulating cell size control in the G1 phase of budding yeast.
• To differentiate between direct regulators of size control and indirect modulators of cell growth.
• To uncover novel mechanisms and networks involved in maintaining cellular size.

Main Methods:

• High-throughput imaging and analysis of millions of individual budding yeast cells.
• Systematic screening of 591 mutants implicated in cell size control.
• Development of quantitative metrics to distinguish direct size control mechanisms from growth effects.

Main Results:

• Identified 17 negative and dozens of positive regulators of cell size control.
• Discovered a small network of negative regulators centered on the mitotic exit network.
• Observed distinct roles for small and large ribosomal subunit components in size control versus cell growth.
• Revealed an additional size control mechanism operating in the G2/M phase.

Conclusions:

• The study provides a comprehensive map of cell size control regulators in budding yeast.
• Negative regulators of size control are organized in a specific network, implicating mitotic exit.
• Ribosomal subunit composition plays a differential role in cell size regulation.
• A secondary size control mechanism in G2/M complements the primary G1 control, offering new insights into yeast cell size homeostasis.