CDK-dependent phosphorylation of Alp7–Alp14 (TACC–TOG) promotes its nuclear accumulation and spindle microtubule assembly
| Autor: | Takashi Toda, Naoyuki Okada, Masamitsu Sato, Masayuki Yamamoto |
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| Rok vydání: | 2014 |
| Předmět: |
Molecular Sequence Data
Active Transport Cell Nucleus Polo-like kinase Biology environment and public health Microtubules Spindle pole body Phragmosome Amino Acid Sequence Phosphorylation Molecular Biology Mitosis Cell Nucleus Nuclear Export Signals Cell Cycle Articles Cell Biology Cyclin-Dependent Kinases Protein Structure Tertiary Spindle apparatus Cell biology Mitotic exit Ran Schizosaccharomyces pombe Proteins Microtubule-Associated Proteins Protein Processing Post-Translational Multipolar spindles Protein Binding |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| DOI: | 10.1091/mbc.e13-11-0679 |
| Popis: | Alp7–Alp14 (TACC–TOG) is a microtubule-associated protein complex that undergoes nucleocytoplasmic shuttling. Alp7 and Alp14 have the NLS and NES responsible for the shuttling, respectively. At mitotic entry, the cyclin-dependent kinase phosphorylates Alp7, resulting in accumulation of the complex to the nucleus, which promotes spindle assembly. As cells transition from interphase to mitosis, the microtubule cytoskeleton is reorganized to form the mitotic spindle. In the closed mitosis of fission yeast, a microtubule-associated protein complex, Alp7–Alp14 (transforming acidic coiled-coil–tumor overexpressed gene), enters the nucleus upon mitotic entry and promotes spindle formation. However, how the complex is controlled to accumulate in the nucleus only during mitosis remains elusive. Here we demonstrate that Alp7–Alp14 is excluded from the nucleus during interphase using the nuclear export signal in Alp14 but is accumulated in the nucleus during mitosis through phosphorylation of Alp7 by the cyclin-dependent kinase (CDK). Five phosphorylation sites reside around the nuclear localization signal of Alp7, and the phosphodeficient alp7-5A mutant fails to accumulate in the nucleus during mitosis and exhibits partial spindle defects. Thus our results reveal one way that CDK regulates spindle assembly at mitotic entry: CDK phosphorylates the Alp7–Alp14 complex to localize it to the nucleus. |
| Databáze: | OpenAIRE |
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