2. Academic Validation
  3. Structure and regulation of human epithelial cell transforming 2 protein

Structure and regulation of human epithelial cell transforming 2 protein

  • Proc Natl Acad Sci U S A. 2020 Jan 14;117(2):1027-1035. doi: 10.1073/pnas.1913054117.
Mengran Chen 1 2 3,  Han Pan 1 2,  Lingfei Sun 2,  Peng Shi 4,  Yikan Zhang 2,  Le Li 2,  Yuxing Huang 4,  Jianhui Chen 2,  Peng Jiang 2,  Xianyang Fang 2,  Congying Wu 4,  Zhucheng Chen 5 2
Affiliations

Affiliations

  • 1 Ministry of Education Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China.
  • 2 School of Life Science, Tsinghua University, Beijing 100084, China.
  • 3 Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, Beijing 100084, China.
  • 4 Institute of Systems Biomedicine, School of Basic Medical Sciences, Peking University, Beijing 100191, China.
  • 5 Ministry of Education Key Laboratory of Protein Science, Tsinghua University, Beijing 100084, China; zhucheng_chen@tsinghua.edu.cn.
PMID: 31888991 DOI: 10.1073/pnas.1913054117
Abstract

Epithelial cell transforming 2 (Ect2) protein activates Rho GTPases and controls cytokinesis and many other cellular processes. Dysregulation of Ect2 is associated with various cancers. Here, we report the crystal structure of human Ect2 and complementary mechanistic analyses. The data show the C-terminal PH domain of Ect2 folds back and blocks the canonical RhoA-binding site at the catalytic center of the DH domain, providing a mechanism of Ect2 autoinhibition. Ect2 is activated by binding of GTP-bound RhoA to the PH domain, which suggests an allosteric mechanism of Ect2 activation and a positive-feedback loop reinforcing RhoA signaling. This bimodal RhoA binding of Ect2 is unusual and was confirmed with Förster resonance energy transfer (FRET) and hydrogen-deuterium exchange mass spectrometry (HDX-MS) analyses. Several recurrent cancer-associated mutations map to the catalytic and regulatory interfaces, and dysregulate Ect2 in vitro and in vivo. Together, our findings provide mechanistic insights into Ect2 regulation in normal cells and under disease conditions.

Keywords

Ect2; RhoA; biophysics; cancer; cytokinesis.

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