Aurora A and cortical flows promote polarization and cytokinesis by inducing asymmetric ECT-2 accumulation

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Abstract

In the early C. elegans embryo, cell polarization and cytokinesis are interrelated yet distinct processes. Here, we sought to understand a poorly understood aspect of cleavage furrow positioning. Early C. elegans embryos deficient in the cytokinetic regulator centralspindlin form furrows, due to an inhibitory activity that depends on aster positioning relative to the polar cortices. Here, we show polar relaxation is associated with depletion of cortical ECT-2, a RhoGEF, specifically at the posterior cortex. Asymmetric ECT-2 accumulation requires intact centrosomes, Aurora A (AIR-1), and myosin-dependent cortical flows. Within a localization competent ECT-2 fragment, we identified three putative phospho-acceptor sites in the PH domain of ECT-2 that render ECT-2 responsive to inhibition by AIR-1. During both polarization and cytokinesis, our results suggest that centrosomal AIR-1 breaks symmetry via ECT-2 phosphorylation; this local inhibition of ECT-2 is amplified by myosin-driven flows that generate regional ECT-2 asymmetry. Together, these mechanisms cooperate to induce polarized assembly of cortical myosin, contributing to both embryo polarization and cytokinesis.

Data availability

The data generated or analyzed during this study are included in the manuscript and in the associated source data files. Image files, raw image analysis data, image analysis scripts, R data files and plasmid sequences are uploaded to Zenodo at doi:10.5281/zenodo.7415982.

The following data sets were generated

1. Longhini KM
2. Glotzer M
(2022) Aurora A and cortical flows promote polarization and cytokinesis by inducing asymmetric ECT-2 accumulation - Data Archive
Zenodo, doi:10.5281/zenodo.7415982.

https://zenodo.org/record/7415982

Article and author information

Author details

Katrina M Longhini

University of Chicago, Chicago, United States

Competing interests
The authors declare that no competing interests exist.
Michael Glotzer

University of Chicago, Chicago, United States

For correspondence
mglotzer@uchicago.edu

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-8723-7232

Funding

National Institute of General Medical Sciences (R35GM127091)

Katrina M Longhini

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.