Heteromeric interactions between the catalytically impaired human epidermal growth factor receptor (HER3/ERBB3) and its catalytically active homologs EGFR and HER2 are essential for their signaling. Different ligands can activate these receptor pairs but lead to divergent signaling outcomes through mechanisms that remain largely unknown. We used stochastic optical reconstruction microscopy (STORM) with pair-correlation analysis to show that EGF and neuregulin (NRG) can induce different extents of HER3 clustering that are dependent on the nature of the coexpressed HER receptor. We found that the presence of these clusters correlated with distinct patterns and mechanisms of receptor phosphorylation. NRG induction of HER3 phosphorylation depended on the formation of the asymmetric kinase dimer with EGFR in the absence of detectable higher-order oligomers. Upon EGF stimulation, HER3 paralleled previously observed EGFR behavior and formed large clusters within which HER3 was phosphorylated via a noncanonical mechanism. HER3 phosphorylation by HER2 in the presence of NRG proceeded through still another mechanism and involved the formation of clusters within which receptor phosphorylation depended on asymmetric kinase dimerization. Our results demonstrate that the higher-order organization of HER receptors is an essential feature of their ligand-induced behavior and plays an essential role in lateral cross-activation of the receptors. We also show that HER receptor ligands exert unique effects on signaling by modulating this behavior.
|Original language||English (US)|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - Apr 4 2017|
Bibliographical noteFunding Information:
We thank Z. Gartner, J. Kung, N. Michael, and T. M. Thaker for critical reading of the manuscript and insightful discussions, S. Liang for many valuable insights; and R. McGorty and V. Pessino from the Huang laboratory for valuable assistance with STORM imaging and helpful discussions. This work was supported by American Cancer Society Postdoctoral Fellowship 124801-PF-13-365-01-TBE (to B.v.L.), National Institute of General Medical Sciences Grant R01 GM109176 (to N.J.), and National Institutes of Health New Innovator Award (DP2 OD008479 (to B.H.).
- EGFR activation
- HER/ERBB receptors
- Receptor clustering
- Receptor tyrosine kinase signaling