Dynein achieves processive motion using both stochastic and coordinated stepping.
Processivity, the ability of single molecules to move continuously along a track, is a fundamental requirement of cargo-transporting molecular motors. Here, we investigate how cytoplasmic dynein, a homodimeric, microtubule-based motor, achieves processive motion. To do this, we developed a versatile method for assembling Saccharomyces cerevisiae dynein heterodimers, using complementary DNA oligonucleotides covalently linked to dynein monomers labeled with different organic fluorophores. Using two-color, single-molecule microscopy and high-precision, two-dimensional tracking, we find that dynein has a highly variable stepping pattern that is distinct from all other processive cytoskeletal motors, which use 'hand-over-hand' mechanisms. Uniquely, dynein stepping is stochastic when its two motor domains are close together. However, coordination emerges as the distance between motor domains increases, implying that a tension-based mechanism governs these steps. This plasticity may allow tuning of dynein for its diverse cellular functions.
Department of Cell Biology, Harvard Medical School, Boston, Massachusetts, USA.
Weihong
W
Qiu
Nathan D
ND
Derr
Brian S
BS
Goodman
Elizabeth
E
Villa
David
D
Wu
William
W
Shih
Samara L
SL
Reck-Peterson
D004398:Dyneins / Q000378:metabolism*; D005456:Fluorescent Dyes / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000379:methods; D008958:Models, Molecular; D009038:Motion; D009841:Oligonucleotides / Q000378:metabolism; D055503:Protein Multimerization; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D013194:Staining and Labeling / Q000379:methods
D005456:Fluorescent Dyes; D009841:Oligonucleotides; D004398:Dyneins