Nucleocytoplasmic transport of Alp7/TACC organizes spatiotemporal microtubule formation in fission yeast

EMBO Rep. 2009 Oct;10(10):1161-7. doi: 10.1038/embor.2009.158. Epub 2009 Aug 21.

Abstract

Ran GTPase activates several target molecules to induce microtubule formation around the chromosomes and centrosomes. In fission yeast, in which the nuclear envelope does not break down during mitosis, Ran targets the centrosomal transforming acidic coiled-coil (TACC) protein Alp7 for spindle formation. Alp7 accumulates in the nucleus only during mitosis, although its underlying mechanism remains elusive. Here, we investigate the behaviour of Alp7 and its binding partner, Alp14/TOG, throughout the cell cycle. Interestingly, Alp7 enters the nucleus during interphase but is subsequently exported to the cytoplasm by the Exportin-dependent nuclear export machinery. The continuous nuclear export of Alp7 during interphase is essential for maintaining the array-like cytoplasmic microtubule structure. The mitosis-specific nuclear accumulation of Alp7 seems to be under the control of cyclin-dependent kinase (CDK). These results indicate that the spatiotemporal regulation of microtubule formation is established by the Alp7/TACC-Alp14/TOG complex through the coordinated interplay of Ran and CDK.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Cyclin-Dependent Kinases / metabolism
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Microtubules / metabolism*
  • Protein Binding
  • Protein Interaction Domains and Motifs*
  • Schizosaccharomyces / genetics
  • Schizosaccharomyces / metabolism*
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism*
  • ran GTP-Binding Protein / genetics
  • ran GTP-Binding Protein / metabolism

Substances

  • Alp7 protein, S pombe
  • Microtubule-Associated Proteins
  • Schizosaccharomyces pombe Proteins
  • alp14 protein, S pombe
  • Cyclin-Dependent Kinases
  • ran GTP-Binding Protein