RT Journal Article
SR Electronic
T1 Working strokes produced by curling protofilaments at disassembling microtubule tips can be biochemically tuned and vary with species
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.09.13.507824
DO 10.1101/2022.09.13.507824
A1 Murray, Lucas E.
A1 Kim, Haein
A1 Rice, Luke M.
A1 Asbury, Charles L.
YR 2022
UL http://biorxiv.org/content/early/2022/09/14/2022.09.13.507824.abstract
AB The disassembly of microtubules can generate force and drive intracellular motility. During mitosis, chromosomes remain persistently attached via kinetochores to the tips of disassembling microtubules, which pull the sister chromatids apart. According to the conformational wave hypothesis, such force generation requires that protofilaments curl outward from the disassembling tips to exert pulling force directly on kinetochores. Rigorously testing this idea will require modifying the mechanical and energetic properties of curling protofilaments, but no way to do so has yet been described. Here, by direct measurement of working strokes generated in vitro by curling protofilaments, we show that their mechanical energy output can be increased by adding magnesium, and that yeast microtubules generate larger and more energetic working strokes than bovine microtubules. Both the magnesium and species-dependent increases in work output can be explained by a lengthening of protofilament curls, without any change in their bending stiffness or intrinsic curvature. These observations demonstrate how work output from curling protofilaments can be tuned and suggest evolutionary conservation of the amount of curvature strain energy stored in the microtubule lattice.Competing Interest StatementThe authors have declared no competing interest.