A myosin filament cage drives multiple aspects of mitosis unique to cells dividing within a polarized epithelium

A never-before-seen myosin filament cage forms in mouse intestinal organoids during rounded metaphase, showing apical/basal polarity and resisting tissue pressure to maintain roundness.

• Why it matters: Division within polarized epithelia requires mitotic behaviors not captured by models of free-floating cells, but the specific mechanics and structures involved remain unclear.
• What they did: Using mouse intestinal organoids with endogenously tagged myosin, super-resolution imaging characterized cage formation and polarity, and cage function was attenuated to test effects on mitosis.
• The result: Attenuating cage function inhibited interkinetic nuclear migration and metaphase rounding, shifted the division plane from planar to orthogonal, and produced organoids with multiple lumens originating at stacked daughter-cell interfaces.