Department of Cancer Biology
Animals; Binding Sites; Cell Cycle; Cell Cycle Proteins; Fibroblasts; Guanosine Triphosphate; Hela Cells; Humans; Mice; Microtubule-Associated Proteins; Microtubules; Mitotic Spindle Apparatus; NIH 3T3 Cells; Neoplasm Proteins; Neoplasms; Nuclear Proteins; Nucleotides; Ovum; Protein Binding; Proteomics; Xenopus; ran GTP-Binding Protein
Life Sciences | Medicine and Health Sciences
Aberrant cell division is a hallmark of cancer, but the molecular circuitries of this process in tumor cells are not well understood. Here, we used a high-throughput proteomics screening to identify novel molecular partners of survivin, an essential regulator of mitosis overexpressed in cancer. We found that survivin associates with the small GTPase Ran in an evolutionarily conserved recognition in mammalian cells and Xenopus laevis extracts. This interaction is regulated during the cell cycle, involves Ran-GTP, requires a discrete binding interface centered on Glu65 in survivin, and is independent of the Ran effector Crm1. Disruption of a survivin-Ran complex does not affect the assembly of survivin within the chromosomal passenger complex or its cytosolic accumulation, but it inhibits the delivery of the Ran effector molecule TPX2 to microtubules. In turn, this results in aberrant mitotic spindle formation and chromosome missegregation in tumor, but not normal, cells. Therefore, survivin is a novel effector of Ran signaling, and this pathway may be preferentially exploited for spindle assembly in tumor cells.
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Citation: Mol Cell Biol. 2008 Sep;28(17):5299-311. Epub 2008 Jun 30. Link to article on publisher's site