Mobile and immobile contractomeres coexist in the same cell. (A) Frames from time-lapse showing contractomere motility during cell extrusion in maturing monolayer. Arrowheads track the location of a stationary ZO-1 density. Graph shows inter-contractomere distance between a motile contractomere (yellow circle) and a relatively immobile contractomere (white circle). Pink circle tracks the movement of a second motile contractomere next to the extruding cell (pink asterisk). Scale bar is 5 μm. (B) Frames from time-lapse showing gliding of contractomeres surrounding an extruding cell (white asterisk) in a mature homeostatic monolayer. Contractomere-pairs flanking the apical junction between neighboring cells next to the extrusion event are marked by circles and squares of the same color. During cell extrusion, one contractomere of the pair is stationary (circles) while the other contractomere (squares) move away to extend the junction. The merged image shows the absence of global junction movement. The lower left graph shows the distance traveled by the motile contractomeres of the three contractomere pairs, one is immobile and the other is motile. The lower middle graph shows the distance between two immobile contractomeres in the same cells. The lower right graph shows the distance traveled for all seven motile contractomeres surrounding the extruding cell. The perimeter of the extruding cell is plotted to show the decrease in junctional length correlates with elongation of junctions between neighboring cells. Scale bar is 5 μm. (C) Graph summarizing total net change in junctional lengths from the lower right graph of B. (D) Frames from time-lapse showing gliding of contractomeres around an extruding cell (asterisk) in a mature monolayer. During cell extrusion, contractomeres immediately surrounding the extruding cell (squares) move away from the immobile contractomeres (circles). Merge image shows the absence of global junction movement during cell extrusion. Scale bar is 5 μm.