Periodic Oscillations of Myosin-II Mechanically Proofread Cell-Cell Connections to Ensure Robust Formation of the Cardiac Vessel

Actomyosin networks provide the major contractile machinery for regulating cell and tissue morphogenesis during development. These networks undergo dynamic rearrangements, enabling cells to have a broad range of mechanical actions. How cells integrate different mechanical stimuli to accomplish complicated tasks in vivo remains unclear. Here, we explore this problem in the context of cell matching, where individual cells form precise inter-cellular connections between partner cells. To study the dynamic roles of actomyosin networks in regulating precise cell matching, we focused on the process of heart formation during Drosophila embryogenesis, where selective filopodia-binding adhesions ensure precise cell alignment. We find that non-muscle Myosin II clusters periodically oscillate within cardioblasts with ~4-min intervals. We observe that filopodia dynamics—including protrusions, retraction, binding stabilization, and binding separation—are correlated with the periodic localization of Myosin II clusters at the cell leading edge. Perturbing the Myosin II activity and oscillatory pattern alters the filopodia properties and binding dynamics and results in mismatched cardioblasts. By simultaneously changing the activity of Myosin II and filopodia adhesion levels, we further demonstrate that levels of Myosin II and adhesion are balanced to ensure precise connectivity between cardioblasts. Combined, we propose a mechanical proofreading machinery of robust cell matching, whereby oscillations of Myosin II within cardioblasts periodically probe filopodia adhesion strength and ensure correct cell-cell connection formation. [Display omitted] •Myosin II shows periodic oscillations with 4–5 min intervals in cardioblasts (CBs)•CB filopodia dynamics and mechanics correlate with Myosin II activity•Altering Myosin II activity and filopodia adhesion leads to perturbed CB matching•Together, Myosin II and filopodia adhesion mechanically proofread cell matching How mechanics regulates the formation of precise cell-cell connections remains unclear. Zhang et al. show that in the embryonic Drosophila heart, periodic contractions generated by Myosin II oscillations, together with differential filopodia adhesions, proofread cell-cell connections, ensuring precise cell matching and robust heart formation.