Models of dynamic extraction of lipid tethers from cell membranes

TL;DR

This paper presents a phenomenological model describing how membrane tethers form when a ligand pulls on membrane receptors, highlighting the influence of force loading rates and velocities on tether formation and length.

Contribution

It introduces a new model for membrane tether formation based on Hooke's law and critical detachment force, providing insights into the conditions favoring tether extrusion.

Findings

Tether formation occurs only within specific force loading rate ranges.

The model predicts the mean tether length at ligand detachment.

Optimal pulling velocities maximize tether length.

Abstract

When a ligand that is bound to an integral membrane receptor is pulled, the membrane and the underlying cytoskeleton can deform before either the membrane delaminates from the cytoskeleton or the ligand detaches from the receptor. If the membrane delaminates from the cytoskeleton, it may be further extruded and form a membrane tether. We develop a phenomenological model for this processes by assuming that deformations obey Hooke's law up to a critical force at which the cell membrane locally detaches from the cytoskeleton and a membrane tether forms. We compute the probability of tether formation and show that they can be extruded only within an intermediate range of force loading rates and pulling velocities. The mean tether length that arises at the moment of ligand detachment is computed as are the force loading rates and pulling velocities that yield the longest tethers.