Remodelling of actin cortical network by α-actinin affects microtubule-actin interactions during cytokinesis

Abstract

Cytokinesis requires the proper interactions between microtubules and actin filaments (F-actin) at the equatorial region. Our recent study demonstrated that remodelling of F-actin by α-actinin is required for proper furrow ingression. However, the roles of F-actin remodelling by α-actinin in microtubule-actin interactions remain poorly understood. I have analysed the effects of modulation of F-actin crosslinking on microtubule organisation by a combination of molecular manipulations and imaging-based techniques. The increased crosslinking of F-actin by overexpression of α-actinin caused a disruption in the organisation of astral microtubules at the equatorial region. In addition, the proper bundling of astral and midzone microtubules was not achieved leading to delayed cytokinesis or cytokinesis failure. Excessive crosslinking of F-actin also resulted in mislocalisation of aurora B, a regulator for cytokinesis. Conversely, decreased crosslinking of F-actin by depletion of α-actinin caused abnormal elongation of microtubules in ectopic furrows. My results suggest that crosslinking of F-actin by α-actinin is not only involved in regulating cortical ingression, but also bundling of microtubule in order to achieve precision in cytokinesis.