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Proc Natl Acad Sci U S A. 2017 Apr 4;114(14):E2836-E2845. doi: 10.1073/pnas.1617994114. Epub 2017 Mar 20.

EGF and NRG induce phosphorylation of HER3/ERBB3 by EGFR using distinct oligomeric mechanisms.

Author information

1
Cardiovascular Research Institute, University of California, San Francisco, CA 94158.
2
School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455.
3
Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158.
4
Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
5
Cardiovascular Research Institute, University of California, San Francisco, CA 94158; natalia.jura@ucsf.edu.
6
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158.

Abstract

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.

KEYWORDS:

EGFR activation; HER/ERBB receptors; STORM; receptor clustering; receptor tyrosine kinase signaling

PMID:
28320942
PMCID:
PMC5389333
DOI:
10.1073/pnas.1617994114
[Indexed for MEDLINE]
Free PMC Article

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