Aurora B‐dependent polarization of the cortical actomyosin network during mitotic exit. (24th August 2021)

• Record Type: Journal Article
• Authors: Ramkumar, Nitya; Patel, Jigna V; Anstatt, Jannis; Baum, Buzz
• Is Part Of: EMBO reports. Volume 22:Number 10(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-24
• Subjects: Aurora B -- polar relaxation -- actomyosin network -- cytokinesis -- cell polarization; Molecular biology -- Periodicals; Molecular Biology -- Periodicals; Molecular biology; Periodicals; 572.8
• DOI: 10.15252/embr.202152387
• Languages: English
• ISSNs: 1469-221X

Abstract

Abstract: The isotropic metaphase actin cortex progressively polarizes as the anaphase spindle elongates during mitotic exit. This involves the loss of actomyosin cortex from opposing cell poles and the accumulation of an actomyosin belt at the cell centre. Although these spatially distinct cortical remodelling events are coordinated in time, here we show that they are independent of each other. Thus, actomyosin is lost from opposing poles in anaphase cells that lack an actomyosin ring owing to centralspindlin depletion. In examining potential regulators of this process, we identify a role for Aurora B kinase in actin clearance at cell poles. Upon combining Aurora B inhibition with centralspindlin depletion, cells exiting mitosis fail to change shape and remain completely spherical. Additionally, we demonstrate a requirement for Aurora B in the clearance of cortical actin close to anaphase chromatin in cells exiting mitosis with a bipolar spindle and in monopolar cells forced to divide while flat. Altogether, these data suggest a novel role for Aurora B activity in facilitating DNA‐mediated polar relaxation at anaphase, polarization of the actomyosin cortex, and cell division. Synopsis: Aurora B facilitates DNA‐mediated polar relaxation at anaphase and polarization of the actomyosin cortex to ensure a robust coupling of anaphase spindle elongation and cytokinesis. The clearance of actin from cell poles at anaphase does not depend on actomyosin ring assembly or on the centralspindlin complex. Aurora B activity is required for clearance of cortical actin network during anaphase and for actin clearance in the vicinity of chromosomes in artificially flattened cells. The role of Aurora B in cortical relaxation is independent of its role in regulating centralspindlin activity. Abstract : Aurora B facilitates DNA‐mediated polar relaxation at anaphase and polarization of the actomyosin cortex to ensure a robust coupling of anaphase spindle elongation and cytokinesis.