On the cellular highway, motor proteins called dyneins rule the road. Dyneins "walk" along structures called microtubules to deliver cellular cargo, such as signaling molecules and organelles, to different parts of a cell. Without dynein on the job, cells cannot divide and people can develop neurological diseases.
Now a new study, which appears in the journal Nature Structural & Molecular Biology, provides the first three-dimensional (3D) visualization of the dynein-dynactin complex bound to microtubules. The study leaders from The Scripps Research Institute (TSRI) report that a protein called dynactin hitches two dyneins together, like a yoke locking together a pair of draft horses.
"If you want a team of horses to move in one direction, you need to line them up," says Gabriel C. Lander, PhD, a TSRI associate professor and senior author of the study. "That's exactly what dynactin is doing to dynein molecules."
More information: Danielle A. Grotjahn et al, Cryo-electron tomography reveals that dynactin recruits a team of dyneins for processive motility, Nature Structural & Molecular Biology (2018). DOI: 10.1038/s41594-018-0027-7 The dynein-dynactin complex (multi-color) motors down a microtubule (green). The four motor domains are shown in yellow. Dynactin (blue) provides the scaffold to keep the two dyneins together. Credit: Danielle Grotjohn, Lander Lab