Abstract
The Ran GTPase controls multiple mitotic processes in Xenopus egg extracts, including mitotic checkpoints, spindle assembly and post-mitotic nuclear envelope reassembly. We have analyzed Ran's role in somatic cells. We uncovered a novel mitotic role of Ran-GTP, involving the Crm1 nuclear export receptor. This pathway is an important mode of Ran-GTP function during mitosis in mammalian somatic cells, which mediates the recruitment of the RanGAP1/RanBP2 complex to kinetochores and maintains the microtubule-based fibers connecting kinetochores to spindle poles (k-fibers). Here we discuss potential implications of these findings for normal k-fiber assembly.
MeSH terms
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Active Transport, Cell Nucleus
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Animals
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Cell Cycle Proteins / metabolism
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Exportin 1 Protein
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GTPase-Activating Proteins / metabolism
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Genome
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Guanine Nucleotide Exchange Factors / metabolism
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Guanosine Triphosphate / chemistry
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Karyopherins / metabolism
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Kinetochores / metabolism*
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Microtubules / metabolism
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Mitosis
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Models, Biological
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Molecular Chaperones / metabolism
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Nuclear Pore Complex Proteins / metabolism
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Nuclear Proteins / metabolism
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Protein Binding
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Receptors, Cytoplasmic and Nuclear / metabolism
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Spindle Apparatus / metabolism
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Xenopus
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Xenopus Proteins / metabolism
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ran GTP-Binding Protein / physiology*
Substances
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Cell Cycle Proteins
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GTPase-Activating Proteins
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Guanine Nucleotide Exchange Factors
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Karyopherins
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Molecular Chaperones
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Nuclear Pore Complex Proteins
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Nuclear Proteins
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RCC1 protein, Xenopus
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RanGAP1 protein, Xenopus
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Receptors, Cytoplasmic and Nuclear
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Xenopus Proteins
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ran-binding protein 2
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Guanosine Triphosphate
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ran GTP-Binding Protein