Membrane-anchored mobile tethers modulate condensate wetting, localization, and migration

Area of Science:

• Biophysics
• Cell Biology
• Physical Chemistry

Background:

• Biomolecular condensates are essential for cellular organization.
• Membrane interactions, mediated by tethers, are critical for condensate function but often overlooked.
• Traditional wetting models do not account for membrane-anchored tethers.

Purpose of the Study:

• To develop a quantitative framework for understanding condensate-membrane interactions.
• To generalize the Young-Dupré equation by incorporating membrane-anchored tethers.
• To investigate how tether density affects condensate wetting behavior.

Main Methods:

• Utilized a surface free-energy framework coupling surface tension and tether density.
• Solved for contact angle and tether density in a spherical cap geometry.
• Developed a wetting phase diagram based on tether-condensate interaction models.

Main Results:

• Generalized the Young-Dupré equation to include tether density.
• Demonstrated that tether density depends non-trivially on interaction strength and form.
• Identified a wetting phase diagram showing transitions from non-wetting to complete wetting.

Conclusions:

• The new framework quantitatively characterizes condensate-membrane interactions.
• Membrane-anchored tethers play a significant role in mediating condensate wetting.
• This work offers potential mechanisms for how membranes organize cellular functions.