Fig. 4: Stress-cell misalignment in LP-9 monolayers.

a Snapshot of an LP-9 island. The experiments on LP-9 cells are repeated 4 times with similar results. b left: Tissue snapshot with the cell shape orientation field n shown as black lines on top of a colour map distinguishing contractile (red) and extensile (blue) regions. Topological defects in the cell shape orientation are indicated by yellow (+1/2) and green (−1/2) symbols. Middle: Snapshots of a region of the same tissue taken 40 min apart showing that the extensile cluster remains fixed. The time axis is from top to bottom. Right: Close-up view of the same tissue. Cell shape orientation is shown in red and stress orientation in white. The color map shows the extensile (blue) and contractile (orange) regions (smoothed). The defect in the cell shape (stress) orientation is shown in yellow (magenta). c Distribution of the misalignment angle θ. Red/blue colouring denotes contractile (θ < 45^o)/extensile (θ > 45^o) values. The LP-9 cells predominantly form contractile regions (compared with Fig. 2b for MDCK cells). d Left: Snapshot from simulations with the cell shape orientation n shown as black lines on top of a colour map distinguishing contractile (red) and extensile (blue) regions. The +1/2 defect in the cell shape is indicated by a yellow arrow. Right: Close-up view of the same tissue. Cell shape orientation is shown in red and stress orientation is white. The color map shows the extensible (blue) and contractile (orange) regions (smoothed). The defect in the cell shape (stress) orientation is shown in yellow (magenta). Source data are provided as a Source Data file⁴⁵.