Scaling of subcellular actin structures with cell length through decelerated growth

Area of Science:

• Cell Biology
• Biophysics
• Cytoskeleton Dynamics

Background:

• Cellular size control is crucial for biological function.
• Previous models focused on scaling with cell volume, often involving limiting pool mechanisms.
• Organelle and structure size regulation relative to cell size remains incompletely understood.

Purpose of the Study:

• To investigate the scaling relationship between subcellular structure size and cell size.
• To determine if cell length or cell volume is the primary determinant of subcellular structure size.
• To elucidate the mechanism by which yeast actin cables achieve size homeostasis.

Main Methods:

• Quantitative imaging of yeast actin cables.
• Mathematical modeling of actin cable extension dynamics.
• Analysis of scaling relationships between cable length and cell dimensions.

Main Results:

• Yeast actin cables exhibit a scaling relationship with cell length, not cell volume.
• Actin cable extension rate decelerates as cables approach the cell rear, matching cell length.
• The deceleration rate of cable extension is proportional to cell length.

Conclusions:

• A novel 'balance-point' model explains actin cable size control.
• This model contrasts with traditional limiting pool mechanisms.
• Cells possess mechanisms to sense and respond to linear dimensions for subcellular structure scaling.