Abstract
Polo-like kinase functions are essential for the establishment of a normal bipolar mitotic spindle, although precisely how Plk1 regulates the spindle is uncertain. In this study, we report that the small GTP/GDP-binding protein Ran is associated with Plk1. Plk1 is capable of phosphorylating co-immunoprecipitated Ran in vitro on serine-135 and Ran is phosphorylated in vivo at the same site during mitosis when Plk1 is normally activated. Cell cultures over-expressing a Ran S135D mutant have significantly higher numbers of abnormal mitotic cells than those over-expressing either wild-type or S135A Ran. The abnormalities in S135D mutant cells are similar to cells over-expressing Plk1. Our data suggests that Ran is a physiological substrate of Plk1 and that Plk1 regulates the spindle organization partially through its phosphorylation on Ran.
Original language | English |
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Pages (from-to) | 144-152 |
Number of pages | 9 |
Journal | Biochemical and Biophysical Research Communications |
Volume | 349 |
Issue number | 1 |
DOIs | |
State | Published - 13 Oct 2006 |
Externally published | Yes |
Keywords
- Cytokinesis
- GTP-binding proteins
- Mitosis
- Plk1
- Polo-like kinases
- Ran