Transverse arcs appear to coalesce from short actin bundles that are generated at the lamellipodial leading edge. The assembly of myosin II into thick filaments also preferentially begins in the region immediately behind the leading edge as it retracts (even in the absence of net protrusion). The transverse arcs mature as the filaments are moved centripetally into the more stable regions of the lamellum. Transverse arcs fully evolve from end-to-end annealing of α-actinin and myosin containing bundles Read more…