Fluctuating Motor Forces Bend Growing Microtubules

• Main Authors: Shekhar, Nandini (Contributor), Neelam, Srujana (Author), Wu, Jun (Author), Ladd, Anthony J. C. (Author), Dickinson, Richard B. (Author), Lele, Tanmay P. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Biological Engineering (Contributor)
• Format: Article
• Language: English
• Published: Springer US, 2017-03-11T00:12:32Z.
• Subjects: Article
• Online Access: Get fulltext

Despite their rigidity, microtubules in living cells bend significantly during polymerization resulting in greater curvature than can be explained by thermal forces alone. However, the source of the non-thermal forces that bend growing microtubules remains obscure. We analyzed the motion of microtubule tips in NIH-3T3 fibroblasts expressing EGFP-EB1, a fluorescent +TIP protein that specifically binds to the growing ends of microtubules. We found that dynein inhibition significantly reduced the deviation of the growing tip from its initial trajectory. Inhibiting myosin modestly reduced tip fluctuations, while simultaneous myosin and dynein inhibition caused no further decrease in fluctuations compared to dynein inhibition alone. Our results can be interpreted with a model in which dynein linkages play a key role in generating and transmitting fluctuating forces that bend growing microtubules.
National Institutes of Health (U.S.) (NIH GM102486)
National Science Foundation (U.S.) (NSF CMMI 0954302, NSF CMMI 0927945, and NSF CTS-0505929)