Crystal clear insights into how the dynein motor moves.

Dyneins are motor proteins that move along microtubules. They have many roles in the cell. They drive the beating of cilia and flagella, move cargos in the cytoplasm and function in the mitotic spindle. Dyneins are large and complex protein machines. Until recently, the way they move was poorly understood. In 2012, two high-resolution crystal structures of the >2500-amino-acid dynein motor domain were published. This Commentary will compare these structures and integrate the findings with other recent studies in order to suggest how dynein works. The dynein motor produces movement in a manner that is distinct from myosin and kinesin, the other cytoskeletal motors. Its powerstroke is produced by ATP-induced remodelling of a protein domain known as the linker. It binds to microtubules through a small domain at the tip of a long stalk. Dynein communicates with the microtubule-binding domain by an unconventional sliding movement of the helices in the stalk coiled-coil. Even the way the two motor domains in a dynein dimer walk processively along the microtubule is unusual.