Role of Importin-β in Coupling Ran to Downstream Targets in Microtubule Assembly
- 26 January 2001
- journal article
- other
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 291 (5504), 653-656
- https://doi.org/10.1126/science.1057661
Abstract
The guanosine triphosphatase Ran stimulates assembly of microtubule asters and spindles in mitoticXenopus egg extracts. A carboxyl-terminal region of the nuclear-mitotic apparatus protein (NuMA), a nuclear protein required for organizing mitotic spindle poles, mimics Ran's ability to induce asters. This NuMA fragment also specifically interacted with the nuclear transport factor, importin-β. We show that importin-β is an inhibitor of microtubule aster assembly in Xenopus egg extracts and that Ran regulates the interaction between importin-β and NuMA. Importin-β therefore links NuMA to regulation by Ran. This suggests that similar mechanisms regulate nuclear import during interphase and spindle assembly during mitosis.Keywords
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