Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

The bipolar mitotic kinesin Eg5 moves on both microtubules that it crosslinks


During cell division, mitotic spindles are assembled by microtubule-based motor proteins1,2. The bipolar organization of spindles is essential for proper segregation of chromosomes, and requires plus-end-directed homotetrameric motor proteins of the widely conserved kinesin-5 (BimC) family3. Hypotheses for bipolar spindle formation include the ‘push–pull mitotic muscle’ model, in which kinesin-5 and opposing motor proteins act between overlapping microtubules2,4,5. However, the precise roles of kinesin-5 during this process are unknown. Here we show that the vertebrate kinesin-5 Eg5 drives the sliding of microtubules depending on their relative orientation. We found in controlled in vitro assays that Eg5 has the remarkable capability of simultaneously moving at 20 nm s-1 towards the plus-ends of each of the two microtubules it crosslinks. For anti-parallel microtubules, this results in relative sliding at 40 nm s-1, comparable to spindle pole separation rates in vivo6. Furthermore, we found that Eg5 can tether microtubule plus-ends, suggesting an additional microtubule-binding mode for Eg5. Our results demonstrate how members of the kinesin-5 family are likely to function in mitosis, pushing apart interpolar microtubules as well as recruiting microtubules into bundles that are subsequently polarized by relative sliding.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Eg5 can slide microtubules apart.
Figure 2: Eg5 moves on both filaments.
Figure 3: Eg5 can keep microtubule ends crosslinked.
Figure 4: Model for the contribution of Eg5 to mitotic spindle morphogenesis.


  1. Scholey, J. M., Brust-Mascher, I. & Mogilner, A. Cell division. Nature 422, 746–752 (2003)

    ADS  CAS  Article  PubMed  Google Scholar 

  2. Compton, D. A. Spindle assembly in animal cells. Annu. Rev. Biochem. 69, 95–114 (2000)

    CAS  Article  PubMed  Google Scholar 

  3. Kashina, A. S., Rogers, G. C. & Scholey, J. M. The bimC family of kinesins: essential bipolar mitotic motors driving centrosome separation. Biochim. Biophys. Acta 1357, 257–271 (1997)

    CAS  Article  PubMed  Google Scholar 

  4. McIntosh, J. R., Hepler, P. K. & Vanwie, D. G. Model for mitosis. Nature 224, 659–663 (1969)

    ADS  Article  Google Scholar 

  5. Sharp, D. J., Rogers, G. C. & Scholey, J. M. Microtubule motors in mitosis. Nature 407, 41–47 (2000)

    ADS  CAS  Article  PubMed  Google Scholar 

  6. Brust-Mascher, I. & Scholey, J. M. Microtubule flux and sliding in mitotic spindles of Drosophila embryos. Mol. Biol. Cell 13, 3967–3975 (2002)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  7. Kashina, A. S. et al. A bipolar kinesin. Nature 379, 270–272 (1996)

    ADS  CAS  Article  PubMed  PubMed Central  Google Scholar 

  8. Sharp, D. J. et al. The bipolar kinesin, KLP61F, cross-links microtubules within interpolar microtubule bundles of Drosophila embryonic mitotic spindles. J. Cell Biol. 144, 125–138 (1999)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  9. Sawin, K. E., Leguellec, K., Philippe, M. & Mitchison, T. J. Mitotic spindle organization by a plus-end-directed microtubule motor. Nature 359, 540–543 (1992)

    ADS  CAS  Article  PubMed  Google Scholar 

  10. Wilde, A. et al. Ran stimulates spindle assembly by altering microtubule dynamics and the balance of motor activities. Nature Cell Biol. 3, 221–227 (2001)

    CAS  Article  PubMed  Google Scholar 

  11. Mayer, T. U. et al. Small molecule inhibitor of mitotic spindle bipolarity identified in a phenotype-based screen. Science 286, 971–974 (1999)

    CAS  Article  PubMed  Google Scholar 

  12. Miyamoto, D. T., Perlman, Z. E., Burbank, K. S., Groen, A. C. & Mitchison, T. J. The kinesin Eg5 drives poleward microtubule flux in Xenopus laevis egg extract spindles. J. Cell Biol. 167, 813–818 (2004)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  13. Kwok, B. H., Yang, J. G. & Kapoor, T. M. The rate of bipolar spindle assembly depends on the microtubule-gliding velocity of the mitotic kinesin Eg5. Curr. Biol. 14, 1783–1788 (2004)

    CAS  Article  PubMed  Google Scholar 

  14. Kapoor, T. M. & Mitchison, T. J. Eg5 is static in bipolar spindles relative to tubulin: evidence for a static spindle matrix. J. Cell Biol. 154, 1125–1133 (2001)

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  15. Kapoor, T. M. & Mitchison, T. J. Allele-specific activators and inhibitors for kinesin. Proc. Natl Acad. Sci. USA 96, 9106–9111 (1999)

    ADS  CAS  Article  PubMed  PubMed Central  Google Scholar 

  16. Howard, J., Hudspeth, A. J. & Vale, R. D. Movement of microtubules by single kinesin molecules. Nature 342, 154–158 (1989)

    ADS  CAS  Article  PubMed  Google Scholar 

  17. Desai, A., Verma, S., Mitchison, T. J. & Walczak, C. E. Kin I kinesins are microtubule-destabilizing enzymes. Cell 96, 69–78 (1999)

    CAS  Article  PubMed  Google Scholar 

  18. Crevel, I. M., Alonso, M. C. & Cross, R. A. Monastrol stabilises an attached low-friction mode of Eg5. Curr. Biol. 14, R411–R412 (2004)

    CAS  Article  PubMed  Google Scholar 

  19. Stock, M. F., Chu, J. & Hackney, D. D. The kinesin family member BimC contains a second microtubule binding region attached to the N terminus of the motor domain. J. Biol. Chem. 278, 52315–52322 (2003)

    CAS  Article  PubMed  Google Scholar 

  20. Crevel, I., Lockhart, A. & Cross, R. A. Kinetic evidence for low chemical processivity in ncd and Eg5. J. Mol. Biol. 273, 160–170 (1997)

    CAS  Article  PubMed  Google Scholar 

  21. McDonald, H. B., Stewart, R. J. & Goldstein, L. S. B. The kinesin-like ncd protein of Drosophila is a minus end-directed microtubule motor. Cell 63, 1159–1165 (1990)

    CAS  Article  PubMed  Google Scholar 

  22. Chui, K. K. et al. Roles of two homotetrameric kinesins in sea urchin embryonic cell division. J. Biol. Chem. 275, 38005–38011 (2000)

    CAS  Article  PubMed  Google Scholar 

  23. Nislow, C., Lombillo, V. A., Kuriyama, R. & McIntosh, J. R. A plus-end-directed motor enzyme that moves antiparallel microtubules in vitro localizes to the interzone of mitotic spindles. Nature 359, 543–547 (1992)

    ADS  CAS  Article  PubMed  Google Scholar 

  24. Gibbons, I. R. & Fronk, E. Latent adenosine-triphosphatase form of dynein-1 from sea urchin sperm flagella. J. Biol. Chem. 254, 187–196 (1979)

    CAS  PubMed  Google Scholar 

  25. Williams, R. C. & Lee, J. C. Preparation of tubulin from brain. Methods Enzymol. 85, 376–385 (1982)

    CAS  Article  PubMed  Google Scholar 

  26. Hyman, A. A. Preparation of marked microtubules for the assay of the polarity of microtubule-based motors by fluorescence. J. Cell Sci. 14 (suppl.), 125–127 (1991)

    CAS  Article  Google Scholar 

  27. van Dijk, M. A., Kapitein, L. C., van Mameren, J., Schmidt, C. F. & Peterman, E. J. G. Combining optical trapping and single-molecule fluorescence spectroscopy: Enhanced photobleaching of fluorophores. J. Phys. Chem. B 108, 6479–6484 (2004)

    CAS  Article  Google Scholar 

Download references


We thank I. Schaap for purifying tubulin, S. Calmat and J. Hendriks for assistance with FPLC chromatography, J. van Mameren for help with software, and M. Korneev, M. Mazur and K. Zabrocka for help with surface chemistry and motility controls. L.C.K. and E.J.G.P. are supported by a VIDI fellowship to E.J.G.P. from the Research Council for Earth and Life Sciences (ALW), with financial aid from the Netherlands Organization for Scientific Research (NWO). T.M.K., B.H.K., J.H.K. are grateful to the NIH/NIGMS for support. Additional support was provided by the Foundation for Fundamental Research on Matter (C.F.S.) and a Research Grant from the Human Frontier Science Program (C.F.S. and T.M.K.).

Author information

Authors and Affiliations


Corresponding authors

Correspondence to Erwin J. G. Peterman or Tarun M. Kapoor.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Video S1

This video complements Figure 1b and Figure 3 in the main text. Eg5-induced relative sliding and end attachment. 20 ×sped up. Total time 160 seconds. (AVI 622 kb)

Supplementary Video S2

This video complements Figure1d in the main text. Eg5-induced relative sliding and end attachment between anti-parallel microtubules. 10 ×sped up. Total time 99 seconds. (AVI 1051 kb)

Supplementary video S3

This video complements Figure1f. Eg5-induced bundling, and polarity sorting of microtubules. 10 × sped up. Total time 110 seconds. (AVI 3157 kb)

Supplementary video S4

This video complements Figure 2a. Eg5 brings microtubule plus ends together. 50 × sped up. Total time 295 seconds. (AVI 533 kb)

Supplementary video S5

This movie complements Figure 2b. The crossing point of crosslinked microtubules moves on both bundles of microtubules. 40 × sped up. Total time 160 seconds. (AVI 360 kb)

Supplementary video S6

This movie complements Figure 2d. Twofold decrease in speed of a microtubule due to orientation change. 16 × sped up. Total time 60 seconds. (AVI 316 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Kapitein, L., Peterman, E., Kwok, B. et al. The bipolar mitotic kinesin Eg5 moves on both microtubules that it crosslinks. Nature 435, 114–118 (2005).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing