There is no life without movement, at all levels of metazoan organization, from individual cells to the animal form. During development, individual cells migrate from the germ layers to lay down the body plan and in the adult organism migrating cells play key roles in immune defense and tissue repair. Tumor dissemination and atherosclerosis, likewise involve cell migration and some bacterial and viral pathogens recruit the motile machinery of cells to propagate their infection. Our studies have focused on unravelling the structural basis of these processes.