Nucleocytoplasmic shuttling of the TACC protein Mia1p/Alp7p is required for remodeling of microtubule arrays during the cell cycle

PLoS One. 2009 Jul 16;4(7):e6255. doi: 10.1371/journal.pone.0006255.

Abstract

Microtubule arrays are remodeled as cells proceed through the cell cycle. It is important to understand how remodeling is regulated in time and space. In fission yeast, the conserved microtubule associated TACC/TOG complex plays an important role in organizing microtubules throughout the cell cycle. Here we show that this complex undergoes nucleocytoplasmic shuttling through the nuclear import and export signals located in the TACC protein Mia1p/Alp7p. When the Crm1p-dependent nuclear export signal of Mia1p is disabled, Mia1p accumulates in the nucleus while its partner protein Alp14p/TOG is restricted to the cytoplasm. This leads to defects in assembly of both interphase arrays and the mitotic spindle. Artificial targeting of Alp14p to the nucleus partially rescues the mitotic spindle defects caused by lack of Mia1p nuclear export. Interestingly, the nuclear export sequence of Mia1p appears to overlap with the Alp14p binding site. We propose that intricate regulation of the subcellular distribution of TACC/TOG complexes drives microtubule array remodeling as cells progress through the cell cycle.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Cycle*
  • Cell Nucleus / metabolism*
  • Cytoplasm / metabolism*
  • Microtubule-Associated Proteins / chemistry
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism
  • Microtubule-Associated Proteins / physiology*
  • Microtubules / metabolism*
  • Mutation
  • Nuclear Export Signals
  • Protein Binding
  • Schizosaccharomyces / cytology*
  • Schizosaccharomyces pombe Proteins / chemistry
  • Schizosaccharomyces pombe Proteins / genetics
  • Schizosaccharomyces pombe Proteins / metabolism
  • Schizosaccharomyces pombe Proteins / physiology*

Substances

  • Alp7 protein, S pombe
  • Microtubule-Associated Proteins
  • Nuclear Export Signals
  • Schizosaccharomyces pombe Proteins