HURP is part of a Ran-dependent complex involved in spindle formation

Curr Biol. 2006 Apr 18;16(8):743-54. doi: 10.1016/j.cub.2006.03.056.


Background: GTP-loaded Ran induces the assembly of microtubules into aster-like and spindle-like structures in Xenopus egg extract. The microtubule-associated protein (MAP), TPX2, can mediate Ran's role in aster formation, but factors responsible for the transition from aster-like to spindle-like structures have not been described.

Results: Here we identify a complex that is required for the conversion of aster-like to spindle-like structures. The complex consists of two characterized MAPs (TPX2, XMAP215), a plus end-directed motor (Eg5), a mitotic kinase (Aurora A), and HURP, a protein associated with hepatocellular carcinoma. Formation and function of the complex is dependent on Aurora A activity. HURP protein was further characterized and shown to bind microtubules and affect their organization both in vitro and in vivo. In egg extract, anti-HURP antibodies disrupt the formation of both Ran-dependent and chromatin and centrosome-induced spindles. HURP is also required for the proper formation and function of mitotic spindles in HeLa cells.

Conclusions: HURP is a new and essential component of the mitotic apparatus. HURP acts as part of a multicomponent complex that affects the growth or stability of spindle MTs and is required for spindle MT organization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aurora Kinases
  • Chromosome Segregation
  • HeLa Cells
  • Humans
  • Microtubule-Associated Proteins / physiology
  • Microtubules / metabolism
  • Multiprotein Complexes
  • Neoplasm Proteins / immunology
  • Neoplasm Proteins / physiology*
  • Protein-Serine-Threonine Kinases / metabolism
  • Protein-Serine-Threonine Kinases / physiology
  • Spindle Apparatus / metabolism*
  • Xenopus
  • Xenopus Proteins / physiology
  • ran GTP-Binding Protein / metabolism


  • CKAP5 protein, Xenopus
  • DLGAP5 protein, human
  • Microtubule-Associated Proteins
  • Multiprotein Complexes
  • Neoplasm Proteins
  • Xenopus Proteins
  • Aurora Kinases
  • Protein-Serine-Threonine Kinases
  • ran GTP-Binding Protein