Neighbor cells restrain furrowing during epithelial cytokinesis

Cytokinesis challenges epithelial tissue homeostasis by generating forces that pull on neighboring cells via cell-cell junctions. Previous work has shown that junction reinforcement at the furrow in Xenopus laevis epithelia regulates the speed of furrowing1. This suggests the cytokinetic array that drives cell division is subject to resistive forces from epithelial neighbor cells. We show here that contractility factors accumulate in neighboring cells near the furrow during cytokinesis. Additionally, increasing neighbor cell stiffness, via [a]-actinin overexpression, or contractility, through optogenetic Rho activation in one neighbor cell, slows or asymmetrically pauses furrowing, respectively. Notably, optogenetic stimulation of neighbor cell contractility on both sides of the furrow induces cytokinetic failure and binucleation. We conclude that forces from the cytokinetic array in the dividing cell are carefully balanced with restraining forces generated by neighbor cells, and neighbor cell mechanics regulate the speed and success of cytokinesis. HighlightsO_LINeighboring cells assemble actomyosin arrays adjacent to the cytokinetic furrow C_LIO_LIOverexpression of an F-actin cross-linker in neighbor cells slows furrowing C_LIO_LIOptogenetic activation of contractility in one neighbor pauses furrow ingression C_LIO_LIHyper-contractility in both neighbors restrains furrowing & cells fail cytokinesis C_LI