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ROCK1 and ROCK2 regulate epithelial polarisation and geometric cell shape
Author(s) -
Kalaji Ruba,
Wheeler Ann P.,
Erasmus Jennifer C.,
Lee Sang Y.,
Endres Robert G.,
Cramer Louise P.,
Braga Vania M.M.
Publication year - 2012
Publication title -
biology of the cell
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.543
H-Index - 85
eISSN - 1768-322X
pISSN - 0248-4900
DOI - 10.1111/boc.201100093
Subject(s) - myosin , myosin light chain kinase , microbiology and biotechnology , biology , myosin light chain phosphatase , rock2 , actin , biophysics , rho associated protein kinase , phosphorylation
Background information Cell–cell adhesion and contraction play an essential role in the maintenance of geometric shape and polarisation of epithelial cells. However, the molecular regulation of contraction during cell elongation leading to epithelial polarisation and acquisition of geometric cell shape is not clear. Results Upon induction of cell–cell adhesion, we find that human keratinocytes acquire specific geometric shapes favouring hexagons, by re‐modelling junction length/orientation and thus neighbour allocation. Acquisition of geometric shape correlates temporally with epithelial polarisation, as shown by an increase in lateral height. ROCK1 and ROCK2 are important regulators of myosin II contraction, but their specific role in epithelial cell shape has not been addressed. Depletion of ROCK proteins interferes with the correct proportion of hexagonal cell shapes and full elongation of lateral domain. Interestingly, ROCK proteins are not essential for maintenance of circumferential thin bundles, the main contractile epithelial F‐actin pool. Instead, ROCK1 or ROCK2 regulates thin bundle contraction and positioning along the lateral domain, an important event for the stabilisation of the elongating lateral domain. Mechanistically, E‐cadherin clustering specifically leads to ROCK1/ROCK2‐dependent inactivation of myosin phosphatase and phosphorylation of myosin regulatory light chain. These events correlate temporally with the increase in lateral height and thin bundle compaction towards junctions. Conclusion We conclude that ROCK proteins are necessary for acquisition of elongated and geometric cell shape, two key events for epithelial differentiation.