4.8 Article

Phosphorylation of the cytokinesis regulator ECT2 at G2/M phase stimulates association of the mitotic kinase Plk1 and accumulation of GTP-bound RhoA

Journal

ONCOGENE
Volume 25, Issue 6, Pages 827-837

Publisher

NATURE PUBLISHING GROUP
DOI: 10.1038/sj.onc.1209124

Keywords

protooncogene; Rho GTPase; exchange factor; polo-box domain; interacting protein

Funding

  1. Intramural NIH HHS Funding Source: Medline

Ask authors/readers for more resources

The epithelial cell transforming gene 2 (ECT2) proto-oncogene encodes a Rho exchange factor, and regulates cytokinesis. ECT2 is phosphorylated in G2/M phases, but its role in the biological function is not known. Here we show that two mitotic kinases, Cdk1 and polo-like kinase 1 (Plk1), phosphorylate ECT2 in vitro. We identified an in vitro Cdk1 phosphorylation site (T412) in ECT2, which comprises a consensus phosphospecific-binding module for the Plk1 polo-box domain (PBD). Endogenous ECT2 in mitotic cells strongly associated with Plk1 PBD, and this binding was inhibited by phosphatase treatment. A phosphorylation-deficient mutant form of ECT2, T412A, did not exhibit strong association with Plk1 PBD compared with wild-type (WT) ECT2. Moreover, ECT2 T412A, but not phosphomimic T412D, displayed a diminished accumulation of GTP-bound RhoA compared with WT ECT2, suggesting that phosphorylation of Thr-412 is critical for the catalytic activity of ECT2. Moreover, while overexpression of WT ECT2 or the T412D mutant caused cortical hyperactivity in U2OS cells during cell division, this activity was not observed in cells expressing ECT2 T412A. These results suggest that ECT2 is regulated by Cdk1 and Plk1 in concert.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.8
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available