Membrane morphologies induced by mixtures of arc-shaped particles with opposite curvature

Biological membranes are shaped by various proteins that either generate inward or outward membrane curvature. In this article, we investigate the membrane morphologies induced by mixtures of arc-shaped particles with coarse-grained modeling and simulations. The particles bind to the membranes either with their inward, concave side or their outward, convex side and, thus, generate membrane curvature of opposite sign. We find that small fractions of convex-binding particles can stabilize three-way junctions of membrane tubules, as suggested for the protein lunapark in the endoplasmic reticulum of cells. For comparable fractions of concave-binding and convex-binding particles, we observe lines of particles of the same type, and diverse membrane morphologies with grooves and bulges induced by these particle lines. The alignment and segregation of the particles is driven by indirect, membrane-mediated interactions.

Automated summary

The study investigates the membrane morphologies induced by proteins of different shapes, finding that a small fraction of convex-binding particles can stabilize three-way junctions of membrane tubules. Additionally, when the ratios of concave-binding and convex-binding particles are comparable, lines of particles of the same type and various membrane morphologies with grooves and bulges are observed on the membranes due to these particle lines. The alignment and segregation of the particles are driven by indirect, membrane-mediated interactions.