Inside the leading edge of a crawling cell, intricate networks of rod-like actin filaments extend toward the cell membrane at various angles, lengthening protein by protein. Upon impact, the crisscrossing rods glance off the membrane and bend as the collective force of myriad filaments pushes the cell forward. How flexible these filaments are, and how effectively they recruit essential regulatory proteins to their cause, depends on the properties of the individual actin proteins composing them. Now, a new study published October 26, 2022 in Nature provides high-resolution structures showing how two key biochemical states of actin work jointly with bending forces to determine how actin can interact with other proteins. The open-access article is titled “Bending Forces and Nucleotide State Jointly Regulate F-Actin Structure.