Ran stimulates spindle assembly by altering microtubule dynamics and the balance of motor activities

Nat Cell Biol. 2001 Mar;3(3):221-7. doi: 10.1038/35060000.


The guanosine tri-phosphatase Ran stimulates assembly of microtubule spindles. However, it is not known what aspects of the microtubule cytoskeleton are subject to regulation by Ran in mitosis. Here we show that Ran-GTP stimulates microtubule assembly by increasing the rescue frequency of microtubules three- to eightfold. In addition to changing microtubule dynamics, Ran-GTP also alters the balance of motor activities, partly as a result of an increase in the amount of motile Eg5, a plus-end-directed microtubule motor that is essential for spindle formation. Thus, Ran regulates multiple processes that are involved in spindle assembly.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Chromatin / metabolism
  • Dimethyl Sulfoxide / pharmacology
  • Kinesin / metabolism
  • Microtubules / metabolism*
  • Molecular Motor Proteins / metabolism*
  • Oocytes / chemistry
  • Oocytes / metabolism
  • Paclitaxel / pharmacology
  • Proto-Oncogene Proteins c-mos / pharmacology
  • Spindle Apparatus / drug effects
  • Spindle Apparatus / physiology*
  • Xenopus Proteins*
  • Xenopus laevis
  • ran GTP-Binding Protein / metabolism*


  • Chromatin
  • KIF11 protein, Xenopus
  • Molecular Motor Proteins
  • Xenopus Proteins
  • Proto-Oncogene Proteins c-mos
  • Kinesin
  • ran GTP-Binding Protein
  • Paclitaxel
  • Dimethyl Sulfoxide