Mitochondrial function regulates cell growth kinetics to maintain mitochondrial homeostasis

Area of Science:

• Cell Biology
• Genetics

Background:

• Mitochondria are inherited, not created de novo, in daughter cells.
• Maintaining mitochondrial homeostasis across cell divisions is vital but poorly understood.

Purpose of the Study:

• To investigate the mechanisms of mitochondrial volume homeostasis during cell division.
• To understand the role of mitochondrial function in cell cycle progression and growth.

Main Methods:

• Utilized a microfluidic yeast "mother machine" to track multiple generations of fission yeast.
• Observed cell size and mitochondrial volume dynamics throughout the cell cycle.
• Conducted quantitative modeling and experiments with mitochondrial DNA-deficient rho0 cells.

Main Results:

• Cell size and mitochondrial volume exhibit exponential growth during the cell cycle.
• Mitochondrial homeostasis depends on the "sizer" mechanism for cell size control.
• Mitochondrial function critically influences cell division timing; cells with less mitochondria grow slower and compensate.
• Mitochondrial addition is adjusted based on initial mitochondrial volume to ensure consistent volume at division.
• Mitochondrial function is essential for driving exponential cellular growth.

Conclusions:

• Mitochondrial activity plays a key role in regulating cellular growth rates.
• The study demonstrates a mechanism ensuring mitochondrial volume homeostasis across cell generations.
• Mitochondrial function is integral to both cell growth and division timing.