Microtubule Dynamics and Oscillating State for Mitotic Spindle

TL;DR

This paper proposes a physical mechanism based on microtubule polymerization and Brownian ratchet dynamics that explains mitotic spindle oscillations, offering a new perspective beyond motor protein-based models.

Contribution

It introduces a novel physical model combining microtubule dynamics and motor effects to explain spindle oscillations and provides a detailed phase diagram of oscillating states.

Findings

Microtubule polymerization can induce spindle oscillations.

The Brownian ratchet model explains force generation on the spindle.

Combined effects of microtubules and motor proteins produce diverse oscillation regimes.

Abstract

We present a physical mechanism that can cause the mitotic spindle to oscillate. The driving force for this mechanism emerges from the polymerization of astral microtubules interacting with the cell cortex. We show that Brownian ratchet model for growing microtubules reaching the cell cortex, mediate an effective mass to the spindle body and therefore force it to oscillate. We compare the predictions of this mechanism with the previous mechanisms which were based on the effects of motor proteins. Finally we combine the effects of microtubules polymerization and motor proteins, and present the detailed phase diagram for possible oscillating states.