Pearling in cells: A clue to understanding cell shape

TL;DR

This paper investigates the pearling instability in cells caused by actin cytoskeleton disruption, providing a theoretical model that links cell shape changes to actin shell properties and boundary conditions.

Contribution

It introduces a quantitative theory explaining pearling instability based on actin shell rigidity and tension, enabling estimation of actin shell properties from shape measurements.

Findings

Pearling wavelength scales with the square root of drug concentration.

The theory accurately predicts shape changes in both adherent and nonadherent cell edges.

Estimates of actin shell rigidity and thickness are derived from shape analysis.

Abstract

Gradual disruption of the actin cytoskeleton induces a series of structural shape changes in cells leading to a transformation of cylindrical cell extensions into a periodic chain of "pearls". Quantitative measurements of the pearling instability give a square-root behavior for the wavelength as a function of drug concentration. We present a theory that explains these observations in terms of the interplay between rigidity of the submembranous actin shell and tension that is induced by boundary conditions set by adhesion points. The theory allows estimation of the rigidity and thickness of this supporting shell. The same theoretical considerations explain the shape of nonadherent edges in the general case of untreated cells.