A myosin chaperone, UNC-45A, is a novel regulator of intestinal epithelial barrier integrity and repair

Lechuga, S.; Cartagena-Rivera, A. X.; Khan, A.; Crawford, B. I.; Narayanan, V.; Conway, D. E.; Lehtimaki, J.; Lappalainen, P.; Rieder, F.; Longworth, M. S.; Ivanov, A. I.

doi:10.1101/2021.11.10.467974

bioRxiv · 10.1101/2021.11.10.467974

A myosin chaperone, UNC-45A, is a novel regulator of intestinal epithelial barrier integrity and repair

Lechuga, S.·Cartagena-Rivera, A. X.·Khan, A.·Crawford, B. I.·Narayanan, V.·Conway, D. E.·Lehtimaki, J.·Lappalainen, P.·Rieder, F.·Longworth, M. S.·Ivanov, A. I.

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Abstract

The actomyosin cytoskeleton serves as a key regulator of the integrity and remodeling of epithelial barriers by controlling assembly and functions of intercellular junctions and cell-matrix adhesions. While biochemical mechanisms that regulate activity of non-muscle myosin II (NM-II) in epithelial cells have been extensively investigated, little is known about assembly of the contractile myosin structures at the epithelial adhesion sites. UNC-45A is a cytoskeletal chaperone that is essential for proper folding of NM II heavy chains and myofilament assembly. We found abundant expression of UNC-45A in human intestinal epithelial cell (IEC) lines and in the epithelial layer of the normal human colon. Interestingly, protein levels of UNC-45A were decreased in colonic epithelium of patients with ulcerative colitis. CRISPR/Cas9-mediated knock-out of UNC-45A in HT-29 and SK-CO15 IEC disrupted epithelial barrier integrity, impaired assembly of epithelial adherence and tight junctions and attenuated cell migration. Consistently, decreased UNC-45 expression increased permeability of the Drosophila gut in vivo. The mechanisms underlying barrier disruptive and anti-migratory effects of UNC-45A depletion involved disorganization of the actomyosin bundles at epithelial junctions and the migrating cell edge. Loss of UNC-45A also decreased contractile forces at epithelial junctions and matrix adhesions. Expression of deletion mutants revealed roles for the myosin binding domain of UNC-45A in controlling IEC junctions and motility. Our findings uncover a novel mechanism that regulates integrity and restitution of the intestinal epithelial barrier, which may be impaired during mucosal inflammation.

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Lechuga, S., Cartagena-Rivera, A. X., Khan, A., Crawford, B. I., Narayanan, V., Conway, D. E., Lehtimaki, J., Lappalainen, P., Rieder, F., Longworth, M. S., Ivanov, A. I.. 2021-11-11. A myosin chaperone, UNC-45A, is a novel regulator of intestinal epithelial barrier integrity and repair. https://doi.org/10.1101/2021.11.10.467974

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