2. Academic Validation
  3. TRAF4 binds to the juxtamembrane region of EGFR directly and promotes kinase activation

TRAF4 binds to the juxtamembrane region of EGFR directly and promotes kinase activation

  • Proc Natl Acad Sci U S A. 2018 Nov 6;115(45):11531-11536. doi: 10.1073/pnas.1809599115.
Gang Cai 1 2,  Liang Zhu 3,  Xing Chen 2,  Kevin Sun 2 4,  Caini Liu 2,  Ganes C Sen 2,  George R Stark 5,  Jun Qin 6,  Xiaoxia Li 7
Affiliations

Affiliations

  • 1 Department of Laboratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, China.
  • 2 Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195.
  • 3 Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195.
  • 4 Department of Biology, University of Pennsylvania, Philadelphia, PA 19104.
  • 5 Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195 starkg@ccf.org qinj@ccf.org lix@ccf.org.
  • 6 Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; starkg@ccf.org qinj@ccf.org lix@ccf.org.
  • 7 Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195; starkg@ccf.org qinj@ccf.org lix@ccf.org.
PMID: 30352854 DOI: 10.1073/pnas.1809599115
Abstract

The activation of the epidermal growth factor receptor (EGFR) is crucial for triggering diverse cellular functions, including cell proliferation, migration, and differentiation, and up-regulation of EGFR expression or activity is a key factor in triggering the development of Cancer. Here we show that overexpression of a scaffold protein, tumor necrosis factor receptor (TNF-R)-associated factor 4 (TRAF4), promotes EGF-induced autophosphorylation of EGFR (activation) and downstream signaling, whereas TRAF4 deficiency attenuates EGFR activation and EGF-driven cell proliferation. Using structure-based sequence alignment and NMR spectroscopy, we identified a TRAF4 binding site in the C-terminal half of the juxtamembrane (JM) segment of EGFR, a region known to promote asymmetric dimerization and subsequent activation. Deletion of the TRAF4 binding site led to dramatic defects in EGFR activation and EGF-driven cell proliferation. Specific point mutations in the TRAF4 binding site also resulted in significant attenuation of EGFR activation. Detailed structural examination of the inactive versus active forms of EGFR suggests that TRAF4 binding probably induces a conformational rearrangement of the JM region to promote EGFR dimerization. These results identify a novel mechanism of TRAF4-mediated EGFR activation and signaling.

Keywords

EGF; EGFR; TRAF4; asymmetric.

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