Ran-GTP coordinates regulation of microtubule nucleation and dynamics during mitotic-spindle assembly

Nat Cell Biol. 2001 Mar;3(3):228-34. doi: 10.1038/35060009.


It was recently reported that GTP-bound Ran induces microtubule and pseudo-spindle assembly in mitotic egg extracts in the absence of chromosomes and centrosomes, and that chromosomes induce the assembly of spindle microtubules in these extracts through generation of Ran-GTP. Here we examine the effects of Ran-GTP on microtubule nucleation and dynamics and show that Ran-GTP has independent effects on both the nucleation activity of centrosomes and the stability of centrosomal microtubules. We also show that inhibition of Ran-GTP production, even in the presence of duplicated centrosomes and kinetochores, prevents assembly of a bipolar spindle in M-phase extracts.

MeSH terms

  • Animals
  • Centrosome / metabolism
  • Chromosomes / metabolism
  • DNA Replication
  • Humans
  • Male
  • Microscopy, Fluorescence
  • Microtubules / metabolism*
  • Oocytes / chemistry
  • Oocytes / drug effects
  • Oocytes / metabolism
  • Proto-Oncogene Proteins c-mos / pharmacology
  • Spermatozoa / chemistry
  • Spermatozoa / cytology
  • Spindle Apparatus / physiology*
  • Xenopus laevis
  • ran GTP-Binding Protein / genetics
  • ran GTP-Binding Protein / metabolism*


  • Proto-Oncogene Proteins c-mos
  • ran GTP-Binding Protein