Dynein Pulls Microtubules Without Rotating Its Stalk

Dynein is a motor protein that hydrolyses ATP and moves toward the minus end of a microtubule (MT). A dynein molecule has one to three heavy chains, each consisting of three domains: a head, a stalk and a tail. ATP is bound and hydrolysed in the head, which has a ring-like structure composed of 6 AAA+ domains. The stalk is an antiparallel coiled-coil, 10–15 nm long, and has a nucleotide-dependent MT-binding domain at the tip (1) (Fig. 1). It has been proposed that the nucleotide-dependent binding affinity of the tubulin-binding site at the tip of the stalk is modulated by the two alpha helices in the coiled-coil sliding over each other (2). However, it is not known how a dynein molecule moves along a microtubule (MT).