# Maximal fluctuations of confined actomyosin gels: dynamics of the cell nucleus

## TL;DR

This paper explores how stress fluctuations influence the stochastic movement of the cell nucleus within a viscous gel, revealing an active Casimir-like attraction and a fluctuation maximum at a critical activity level, aligning with experimental observations.

## Contribution

It demonstrates that stress fluctuations induce boundary attraction in non-equilibrium gels and identifies a fluctuation maximum in nuclear deformations at a specific activity level.

## Key findings

- Stress fluctuations cause an effective attraction to boundaries.
- A fluctuation maximum occurs at a critical activity level.
- Results agree with recent experimental data.

## Abstract

We investigate the effect of stress fluctuations on the stochastic dynamics of an inclusion embedded in a viscous gel. We show that, in non-equilibrium systems, stress fluctuations give rise to an effective attraction towards the boundaries of the confining domain, which is reminiscent of an active Casimir effect. We apply this generic result to the dynamics of deformations of the cell nucleus and we demonstrate the appearance of a fluctuation maximum at a critical level of activity, in agreement with recent experiments [E. Makhija, D. S. Jokhun, and G. V. Shivashankar, Proc. Natl. Acad. Sci. U.S.A. 113, E32 (2016)].