https://phys.org/news/2018-05-cell-motility-mystery-crackedthe-protein.html

A major user of ATP in many cell types is the actin cytoskeleton, which is composed of dynamic protein filaments that provide the force for cells to move around and change their shape. For example in neurons and immune cells, approximately half of the ATP is estimated to be consumed in motile and morphogenetic processes driven by ATP-dependent growth of actin filaments. However, the mechanism by which ATP is loaded to actin has remained a mystery.

Researchers at Institute of Biotechnology, University of Helsinki have now discovered that the abundant and evolutionarily conserved protein,cyclase-associated protein, is responsible for re-charging actin monomers with ATP. It converts them into a form that can be used for motile and morphogenetic processes in cells.