1. Nucleocytoplasmic transport of Alp7/TACC organizes spatiotemporal microtubule formation in fission yeast
- Author
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Masayuki Yamamoto, Takashi Toda, Masamitsu Sato, Yasutaka Kakui, Naoyuki Okada, and Minoru Yoshida
- Subjects
Scientific Report ,Active Transport, Cell Nucleus ,Importin ,nuclear transport ,Biology ,Biochemistry ,Microtubules ,Schizosaccharomyces ,Genetics ,Protein Interaction Domains and Motifs ,Nuclear export signal ,Molecular Biology ,Mitosis ,Cytoplasmic microtubule ,Microtubule nucleation ,TACC–TOG ,Cyclin-Dependent Kinases ,Cell biology ,cyclin-dependent kinase ,ran GTP-Binding Protein ,Centrosome ,Ran ,Schizosaccharomyces pombe Proteins ,Nuclear transport ,Ran GTPase ,Microtubule-Associated Proteins ,microtubule ,Protein Binding - 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.
- Published
- 2009