Quantitatively mapping the interaction of HER2 and EGFR on cell membranes with peptide probes.

Human epidermal growth factor receptor-2 (HER2) is a member of the epidermal growth factor receptor (HER) family that is involved in various biological processes such as cell proliferation, survival, differentiation, migration and invasion. It generally functions in the form of homo-/hetero-dimers or oligomers with other HER family members. Although its essential roles in cellular activities have been widely recognized, questions concerning the spatial distribution of HER2 on the membranes and the interactions between it and other ErbB family members remain obscure. Here, we obtained a high-quality dSTORM image of HER2 nanoscale clusters recognized by peptide probes, and found that HER2 forms clusters containing different numbers of molecules on cell membranes. Moreover, we found that HER2 and EGFR formed hetero-oligomers on non-stimulated cell membranes, whereas EGF stimulation reduced the degree of heteromerization, suggesting that HER2 and EGFR hetero-oligomers may inhibit the activation of EGFR. Collectively, our work revealed the clustered distribution of HER2 and quantified the changes of the interaction between HER2 and EGFR in the resting and active states at the single molecular level, which promotes a deeper understanding of the protein-protein interaction on cell membranes.