Kinesin-14 motors participate in a force balance at microtubule plus-ends to regulate dynamic instability
Kinesin-14 molecular motors represent an essential class of proteins that bind microtubules and walk toward their minus-ends. Previous studies have described important roles for Kinesin-14 motors at microtubule minus-ends, but their role in regulating plus-end dynamics remains controversial. Kinesin...
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Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 119; no. 8 |
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Main Authors | , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences
22.02.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Kinesin-14 molecular motors represent an essential class of proteins that bind microtubules and walk toward their minus-ends. Previous studies have described important roles for Kinesin-14 motors at microtubule minus-ends, but their role in regulating plus-end dynamics remains controversial. Kinesin-14 motors have been shown to bind the EB family of microtubule plus-end binding proteins, suggesting that these minus-end-directed motors could interact with growing microtubule plus-ends. In this work, we explored the role of minus-end-directed Kinesin-14 motor forces in controlling plus-end microtubule dynamics. In cells, a Kinesin-14 mutant with reduced affinity to EB proteins led to increased microtubule lengths. Cell-free biophysical microscopy assays were performed using Kinesin-14 motors and an EB family marker of growing microtubule plus-ends, Mal3, which revealed that when Kinesin-14 motors bound to Mal3 at growing microtubule plus-ends, the motors subsequently walked toward the minus-end, and Mal3 was pulled away from the growing microtubule tip. Strikingly, these interactions resulted in an approximately twofold decrease in the expected postinteraction microtubule lifetime. Furthermore, generic minus-end-directed tension forces, generated by tethering growing plus-ends to the coverslip using λ-DNA, led to an approximately sevenfold decrease in the expected postinteraction microtubule growth length. In contrast, the inhibition of Kinesin-14 minus-end-directed motility led to extended tip interactions and to an increase in the expected postinteraction microtubule lifetime, indicating that plus-ends were stabilized by nonmotile Kinesin-14 motors. Together, we find that Kinesin-14 motors participate in a force balance at microtubule plus-ends to regulate microtubule lengths in cells. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Edited by E. Ostap, Pennsylvania Muscle Institute, Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA; received April 29, 2021; accepted January 3, 2022 by Editorial Board Member Yale E. Goldman Author contributions: A.O. and M.K.G. designed research; A.O., S.P., S.M., S.J.G., M.P., and A.G.M. performed research; M.M., E.D., and T.N.D. contributed new reagents/analytic tools; A.O., S.P., S.M., S.J.G., M.P., A.G.M., and M.K.G. analyzed data; and A.O. and M.K.G. wrote the paper. |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.2108046119 |