Shaping of membranes by arc-like particles

This dissertation analyzes the interaction of biomembranes with arc-like particles, which gives rise to complex morphologies of organelles inside cells. The shaping of membranes is investigated with coarse-grained modeling and Monte Carlo simulations. In the coarse-grained model, the membrane is described as a discretized elastic surface, and the particles as segmented arcs. Concave arc-like particles, i.e. particles interacting with the membrane on their concave side, shape membranes by inducing positive curvature at their binding sites. The membrane shape strongly depends on the overall angle and area concentration of the adsorbed particles. Particles with sufficiently large angles can induce both tubules and double-membrane disks, depending on their area concentrations. Double-membrane disks are stabilized by particles that adsorb only to the highly curved edges of the disks, while tubules are fully covered by particles. If mixtures of both concave and convex particles are allowed to bind, morphologies with regions of negative curvature appear on the membrane. A frequently observed membrane morphology resembles a bulged ball, in which concave and convex particles create bulges and invaginations on the membrane, respectively. For small particles and low concentration of convex particles, U-shaped tubular and three-way junction morphologies are observed, which are common in the peripheral endoplasmic reticulum. Finally, this dissertation shows that the membrane-mediated interaction between bound concave particles depends on the overall membrane curvature. The radial distribution function for bound particles is computed, and the membrane-mediated interaction between particles is derived with the reversible work theorem. Membrane curvatures that are compatible with the particle curvature have a weaker membrane-mediated interaction, which indicates that the induction of curvature on the membrane plays an important role for the membrane-mediated particle-particle interactions.

Author dc:creator

• Bonazzi, Francesco

Advisor dc:contributor.advisor

• Klapp, Sabine

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Identifier URI

http://dx.doi.org/10.14279/depositonce-8472

OAI identifier oai:identifier

oai:depositonce.tu-berlin.de:11303/9416