Wrapping pathways of anisotropic dumbbell particles by giant unilamellar vesicles

TL;DR

This study investigates how giant unilamellar vesicles (GUVs) wrap around anisotropic dumbbell-shaped particles, revealing the roles of curvature and tension in the wrapping process through experiments, theory, and simulations.

Contribution

It introduces an experimental and theoretical model for the passive endocytic engulfment of anisotropic objects, highlighting the importance of curvature and tension in the process.

Findings

Curvature variation in the dumbbell neck influences wrapping speed.

Membrane tension affects the final wrapping state.

Distinct stages of the wrapping pathway are identified.

Abstract

Endocytosis is a key cellular process involved in the uptake of nutrients, pathogens or the diagnosis and therapy of diseases. Most studies have focused on spherical objects, whereas biologically relevant shapes can be highly anisotropic. In this letter, we use an experimental model system based on Giant Unilamellar Vesicles (GUVs) and dumbbell-shaped colloidal particles to mimic and investigate the first stage of the passive endocytic process: engulfment of an anisotropic object by the membrane. Our model has specific ligand-receptor interactions realized by mobile receptors on the vesicles and immobile ligands on the particles. Through a series of experiments, theory and molecular dynamics simulations, we quantify the wrapping process of anisotropic dumbbells by GUVs and identify distinct stages of the wrapping pathway. We find that the strong curvature variation in the neck of the dumbbell as well as membrane tension are crucial in determining both the speed of wrapping and the final states.