Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
XB-ART-50156
J Biol Chem 2015 Apr 03;29014:9122-34. doi: 10.1074/jbc.M114.591545.
Show Gene links Show Anatomy links

Phosphorylation of targeting protein for Xenopus kinesin-like protein 2 (TPX2) at threonine 72 in spindle assembly.

Shim SY , Perez de Castro I , Neumayer G , Wang J , Park SK , Sanada K , Nguyen MD .


???displayArticle.abstract???
The human ortholog of the targeting protein for Xenopus kinesin-like protein 2 (TPX2) is a cytoskeletal protein that plays a major role in spindle assembly and is required for mitosis. During spindle morphogenesis, TPX2 cooperates with Aurora A kinase and Eg5 kinesin to regulate microtubule organization. TPX2 displays over 40 putative phosphorylation sites identified from various high-throughput proteomic screenings. In this study, we characterize the phosphorylation of threonine 72 (Thr(72)) in human TPX2, a residue highly conserved across species. We find that Cdk1/2 phosphorylate TPX2 in vitro and in vivo. Using homemade antibodies specific for TPX2 phosphorylated at Thr(72), we show that this phosphorylation is cell cycle-dependent and peaks at M phase. Endogenous TPX2 phosphorylated at Thr(72) does not associate with the mitotic spindle. Furthermore, ectopic GFP-TPX2 T72A preferentially concentrates on the spindle, whereas GFP-TPX2 WT distributes to both spindle and cytosol. The T72A mutant also increases the proportion of cells with multipolar spindles phenotype. This effect is associated with increased Aurora A activity and abnormally elongated spindles, indicative of higher Eg5 activity. In summary, we propose that phosphorylation of Thr(72) regulates TPX2 localization and impacts spindle assembly via Aurora A and Eg5.

???displayArticle.pubmedLink??? 25688093
???displayArticle.pmcLink??? PMC4423697
???displayArticle.link??? J Biol Chem
???displayArticle.grants??? [+]

Species referenced: Xenopus
Genes referenced: kif11 tpx2

References [+] :
Aguirre-Portolés, Tpx2 controls spindle integrity, genome stability, and tumor development. 2012, Pubmed