Oral Presentation 2014 International Biophysics Congress

N-Glycosylation determines structural arrangement of Epidermal Growth Factor Receptor on a membrane (#31)

Karol Kaszuba 1 , Michal Grzybek 2 3 , Adam Orlowski 1 , Reinis Danne 1 , Tomasz Rog 1 , Kai Simons 4 , Ünal Coskun 2 3 , Ilpo Vattulainen 1 5
  1. Physics, Tampere University of Technology, Biological Physics and Soft Matter (BIO) Group, Tampere, Finland
  2. Medical Faculty TU Dresden, Laboratory of Membrane Biochemistry, Paul Langerhans Institute, Dresden, Germany
  3. German Center for Diabetes Research (DZD), Dresden, Germany
  4. Max Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
  5. MEMPHYS – Center for Biomembrane Physics, University of Southern Denmark, Odense, Denmark

The human Epidermal Growth Factor Receptor (EGFR) is a cell surface receptor that belongs to the subfamily of the ErbB receptors. The activation of the EGFR initiates multiple signaling pathways regulating cell proliferation, differentiation, cell survival and metabolism. Not surprisingly, the aberrations within the EGFR-mediated signaling pathways are associated with the development of various cancers. Yet, in spite of a considerable amount of previous work, the activation mechanism of EGFR is still far from being completely understood. That is largely because of technical challenges to determine high-resolution structures of the complete receptor. One of the promising means to unlock the problem is to employ atomistic molecular dynamics (MD) simulations to clarify the conformational properties of the full-length receptor.

Here we used atomistic MD simulations to unravel the role of glycosylation on EGFR conformation. We considered the N-glycosylated human EGFR in different lipid compositions, allowing comparison of simulation results with experimental in vitro reconstitution of the full-length receptor.

Our results emphasize the critical role of Man3GlcNAc2 core glycosylation on EGFR conformation, thereby likely affecting the receptor activation. The attached sugars were shown to affect the conformational arrangement of the EGFR ectodomain on a membrane, the interfacial contact area between the membrane and the ecto- and intracellular domains, the structural stability of the N-terminal dimerization motif within the trans-membrane domain of the receptor, and last but not least the stability of the juxtamembrane domain, playing a role in allosteric regulation of the kinase domain activation. The results of MD simulations were validated by ligand binding assays and epitope mapping with antibodies.