Cytoskeletal organization: whirling to the beat

Abstract

Dense populations of microtubules driven by axonemal dynein form large vortices, providing insights into how simple interactions between individuals can give rise to large-scale coordinated movement, such as that seen in schools of fish and flocks of birds.

Figure 1. Collective behavior at a range of scales

(A) Dense populations of microtubules driven by axonemal dynein c form a lattice of vortices in the filament gliding assay [1]. Scale bar, 1 mm. (B) In 1944, Schneirla [4] described a circular milling formation of ants that persisted for over 12 hours (colloquially called a death spiral because the ants often continue spriraling until they die of exhaustion). (C) Collective motion in dense colonies of Bacillus subtilis bacteria; colored vectors delineate groups and show direction of movement [8]. (D) Image of a single vortex of microtubules driven by axonemal dynein c [1]. Scale bar, 500 µm. (E) Swirls of actin filaments resulting from high densities of actin filaments driven by immobilized myosin [11]. The image is a superposition of ten images, each 1 second apart. Scale bar, 50 µm. (F) Kinesin-driven loops of individual microtubules under crowded microtubule densities in which ~1% of filaments are fluorescently labeled [10]. Scale bar 3 µm.