Dynamics of actomyosin contractile activity during epithelial morphogenesis

► A pulsatile medial actomyosin network drives cell area fluctuations. ► Higher pulse frequencies are required for effective cell contraction. ► Intrinsic cellular mechanisms and anisotropic planar tension polarize cell behaviour. ► Actomyosin ratchet mechanisms are also used to generate effective contraction. ► Actomyosin activity is regulated by both signalling pathways and mechanical cues.