Multispherical shapes of vesicles with intramembrane domains

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Biomembranes undergo phase separation into distinct fluid phases.
• This separation results in vesicles with intramembrane domains (a and b).
• Vesicles can form complex multispherical shapes with interconnected membrane necks.

Purpose of the Study:

• To investigate the morphological complexity of multivesicles formed by phase-separated biomembranes.
• To analyze the stability and shapes of multivesicles using curvature elasticity theory.
• To understand the factors influencing neck stability and vesicle division.

Main Methods:

• Application of the theory of curvature elasticity.
• Analysis of vesicle shapes, specifically two-sphere and multispherical configurations.
• Distinguishing neck types based on effective mean curvature.
• Investigating stability conditions and forces governing neck fission.

Main Results:

• Two-domain vesicles form two-sphere shapes with four distinct morphologies governed by stability conditions.
• Ab-necks experience constriction forces, leading to fission and division with increased line tension or spontaneous curvature.
• Multisphericity with multiple neck types (ab, aa, bb) reduces stability regimes.
• Vesicles with more than two domains exhibit multiple ab-necks.

Conclusions:

• The study characterizes generalized constant-mean-curvature surfaces for multivesicles.
• Morphological complexity is governed by stability conditions and neck properties.
• These findings provide insights into vesicle dynamics and are experimentally accessible using giant vesicle methods.