Spindle Pole Regulation by a Discrete Eg5-Interacting Domain in TPX2

Frank Eckerdt, Patrick A. Eyers, Andrea L. Lewellyn, Claude Prigent, James L. Maller*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Scopus citations

Abstract

Targeting protein for Xklp2 (TPX2) activates the Ser/Thr kinase Aurora A in mitosis and targets it to the mitotic spindle [1, 2]. These effects on Aurora A are mediated by the N-terminal domain of TPX2, whereas a C-terminal fragment has been reported to affect microtubule nucleation [3]. Using the Xenopus system, we identified a novel role of TPX2 during mitosis. Injection of TPX2 or its C terminus (TPX2-CT) into blastomeres of two-cell embryos led to potent cleavage arrest. Despite cleavage arrest, TPX2-injected embryos biochemically undergo multiple rounds of DNA synthesis and mitosis, and arrested blastomeres have abnormal spindles, clustered centrosomes, and an apparent failure of cytokinesis. In Xenopus S3 cells, transfection of TPX2-FL causes spindle collapse, whereas TPX2-CT blocks pole segregation, resulting in apposing spindle poles with no evident displacement of Aurora A. Analysis of TPX2-CT deletion peptides revealed that only constructs able to interact with the class 5 kinesin-like motor protein Eg5 induce the spindle phenotypes. Importantly, injection of Eg5 into TPX2-CT-arrested blastomeres causes resumption of cleavage. These results define a discrete domain within the C terminus of TPX2 that exerts a novel Eg5-dependent function in spindle pole segregation.

Original languageEnglish (US)
Pages (from-to)519-525
Number of pages7
JournalCurrent Biology
Volume18
Issue number7
DOIs
StatePublished - Apr 8 2008

Funding

We thank Dr. Gary Gorbsky (Oklahoma Medical Research Foundation) for the Xenopus S3 cell lines, Dr. Bryn Grimison (University of Colorado Health Sciences Center) for providing Emi1-CT protein, and Dr. Thierry Lorca (CNRS, Montpellier) for Xenopus securin cDNA. We also thank Dr. Johné Liu (Ottawa Health Research Institute) for providing Aurora B antibodies. C.P. is financed by the CNRS, the UICC and the LNCC Equipe Labellisée. F.E. is a Research Associate and J.L.M. an Investigator at the Howard Hughes Medical Institute.

Keywords

  • CELLBIO
  • CELLCYCLE

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences

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