7mn8

Publication Abstract from PubMed

Human epidermal growth factor receptor 2 (HER2) and HER3 form a potent pro-oncogenic heterocomplex(1-3) upon binding of growth factor neuregulin-1beta (NRG1beta). The mechanism by which HER2 and HER3 interact remains unknown in the absence of any structures of the complex. Here we isolated the NRG1beta-bound near full-length HER2-HER3 dimer and, using cryo-electron microscopy, reconstructed the extracellulardomain module, revealing unexpected dynamics at the HER2-HER3 dimerization interface. We show that the dimerization arm of NRG1beta-bound HER3 is unresolved because the apo HER2 monomer does not undergo a ligand-induced conformational change needed to establish a HER3 dimerization arm-binding pocket. In a structure of the oncogenic extracellular domain mutant HER2(S310F), we observe a compensatory interaction with the HER3 dimerization arm that stabilizes the dimerization interface. Both HER2-HER3 and HER2(S310F)-HER3 retain the capacity to bind to the HER2-directed therapeutic antibody trastuzumab, but the mutant complex does not bind to pertuzumab. Our structure of the HER2(S310F)-HER3-NRG1beta-trastuzumab Fab complex reveals that the receptor dimer undergoes a conformational change to accommodate trastuzumab. Thus, similar to oncogenic mutations, therapeutic agents exploit the intrinsic dynamics of the HER2-HER3 heterodimer. The unique features of a singly liganded HER2-HER3 heterodimer underscore the allosteric sensing of ligand occupancy by the dimerization interface and explain why extracellular domains of HER2 do not homo-associate via a canonical active dimer interface.

Structures of the HER2-HER3-NRG1beta complex reveal a dynamic dimer interface.,Diwanji D, Trenker R, Thaker TM, Wang F, Agard DA, Verba KA, Jura N Nature. 2021 Dec;600(7888):339-343. doi: 10.1038/s41586-021-04084-z. Epub 2021 , Nov 10. PMID:34759323^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.