Hepatocytic cells undergo cell divisions out of the monolayer because of a persistent x-z spindle tilt. (A) Schematics representing the spindle orientation in nonpolarized and columnar- or hepatocytic-polarized anaphase cells. The β angle represents the angle between the spindle axis (SA) and the substratum in the x-z dimension. (B and C) MDCK, WIF-B9, and HepG2 cells in late telophase/cytokinesis (B) and anaphase (C) were fixed and stained as indicated. The percentage of cytokinesis with both daughter cells contacting the substratum (B) and the β angle (C) were quantified. n = 20–25 cells/experiment were analyzed for N = 3 independent experiments. ns, not significant, analyzed by t test. Error bars indicate +SD (bar graph) or ±SEM (dot graph). (D) x-z-t confocal time-lapse sequence of a dividing WIF-B9 or HepG2 cell with cell contours outlined by pointed lines. (B and C) Red arrowheads show hepatocytic lateral lumina. (B and D) Black arrowheads show daughter that lost substrate contact.