Scientific Reports (May 2023)

Polarity signaling balances epithelial contractility and mechanical resistance

  • Matthias Rübsam,
  • Robin Püllen,
  • Frederik Tellkamp,
  • Alessandra Bianco,
  • Marc Peskoller,
  • Wilhelm Bloch,
  • Kathleen J. Green,
  • Rudolf Merkel,
  • Bernd Hoffmann,
  • Sara A. Wickström,
  • Carien M. Niessen

DOI
https://doi.org/10.1038/s41598-023-33485-5
Journal volume & issue
Vol. 13, no. 1
pp. 1 – 14

Abstract

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Abstract Epithelia maintain a functional barrier during tissue turnover while facing varying mechanical stress. This maintenance requires both dynamic cell rearrangements driven by actomyosin-linked intercellular adherens junctions and ability to adapt to and resist extrinsic mechanical forces enabled by keratin filament-linked desmosomes. How these two systems crosstalk to coordinate cellular movement and mechanical resilience is not known. Here we show that in stratifying epithelia the polarity protein aPKCλ controls the reorganization from stress fibers to cortical actomyosin during differentiation and upward movement of cells. Without aPKC, stress fibers are retained resulting in increased contractile prestress. This aberrant stress is counterbalanced by reorganization and bundling of keratins, thereby increasing mechanical resilience. Inhibiting contractility in aPKCλ−/− cells restores normal cortical keratin networks but also normalizes resilience. Consistently, increasing contractile stress is sufficient to induce keratin bundling and enhance resilience, mimicking aPKC loss. In conclusion, our data indicate that keratins sense the contractile stress state of stratified epithelia and balance increased contractility by mounting a protective response to maintain tissue integrity.