Formation of adherens junctions leads to the emergence of a tissue-level tension in epithelial monolayers.
Bottom Line: Adherens junctions and desmosomes integrate the cytoskeletons of adjacent cells into a mechanical syncitium.Though much is known about the biological mechanisms underlying junction formation, little is known about how tissue-scale mechanical properties are established.As a consequence, inhibition of any of the molecular mechanisms participating in adherens junction initiation, remodelling and maturation significantly impeded the emergence of tissue-level tension in monolayers.
Affiliation: London Centre for Nanotechnology, University College London, London WC1H 0AH, UK Department of Physics, University College London, London WC1E 6BT, UK Engineering Doctorate Program, Department of Chemistry, University College London, London WC1H 0AJ, UK.Show MeSH
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Mentions: After establishing a sufficiently broad contact, the branched dendritic network of actin is reorganised into a contractile actin belt through myosin contractility and formin-mediated polymerisation of linear F-actin arrays at intercellular junctions (Carramusa et al., 2007; Harris and Tepass, 2010; Kobielak et al., 2004; Tang and Brieher, 2012). Therefore, we investigated the contribution of formins by treatment with the broad spectrum inhibitor SMIFH2 (Rizvi et al., 2009), which has been shown to perturb junctional F-actin in MDCK monolayers (Tang and Brieher, 2012). Upon inhibition of formin activity, intercellular junctions appeared to form normally and some actin remodelling occurred (Fig. 6C,D) but the cells appeared more rounded than those under control conditions after 150 min (Fig. 6B,D). At all time-points, apparent stiffness was significantly lower than under control conditions (Fig. 6G). These results indicated that formin-mediated polymerisation of actin is required for the efficient establishment of monolayer stiffness.
Affiliation: London Centre for Nanotechnology, University College London, London WC1H 0AH, UK Department of Physics, University College London, London WC1E 6BT, UK Engineering Doctorate Program, Department of Chemistry, University College London, London WC1H 0AJ, UK.