The architecture of EGFR’s basal complexes reveals autoinhibition mechanisms in dimers and oligomers

Abstract

Our current understanding of epidermal growth factor receptor (EGFR) autoinhibition is based on X-ray structural data of monomer and dimer receptor fragments and does not explain how mutations achieve ligand-independent phosphorylation. Using a repertoire of imaging technologies and simulations we reveal an extracellular head-to-head interaction through which ligand-free receptor polymer chains of various lengths assemble. The architecture of the head-to-head interaction prevents kinase-mediated dimerisation. The latter, afforded by mutation or intracellular treatments, splits the autoinhibited head-to-head polymers to form stalk-to-stalk flexible non-extended dimers structurally coupled across the plasma membrane to active asymmetric tyrosine kinase dimers, and extended dimers coupled to inactive symmetric kinase dimers. Contrary to the previously proposed main autoinhibitory function of the inactive symmetric kinase dimer, our data suggest that only dysregulated species bear populations of symmetric and asymmetric kinase dimers that coexist in equilibrium at the plasma membrane under the modulation of the C-terminal domain.

Oncogenic mutations at the EGFR ectodomain structurally converge to remove a steric hindrance on a kinase-coupled cryptic epitope

“…Such model assumes that activation happens in preformed dimers (39) (here detected for all ECD variants; SI Appendix, Fig. S5E) can explain mutants' dimerization-independent activity (15) and is supported by recent FRET data (40). Specifically, our data highlight N-TR1 flexibility and orientation as essential pieces to orchestrate ECD-KD coupling.…”

Supramolecular clustering of the cardiac sodium channel Nav1.5 in HEK293F cells, with and without the auxiliary β3‐subunit

“…30 However, recent STORM imaging has revealed that even in the absence of EGF, the EGF receptors form complex oligomers on the plasma membrane, but the EGF binding induced a local geometric rearrangement of these receptors such that the intracellular tyrosine kinase domains could more readily cross-phosphorylate each other. 37 Hence, the enhanced PLA signal following EGF binding most likely reflects this local rearrangement in the pre-existing EGF-receptor clusters, rather than ligand-induced receptor dimerization. It should therefore be emphasized that in studying membrane-bound protein assemblies, super-resolution imaging and PLA-type experiments potentially reflect differing aspects of these supramolecular interactions.…”

“…This has been interpreted to indicate that EGF promotes the dimerization of the EGF receptor . However, recent STORM imaging has revealed that even in the absence of EGF, the EGF receptors form complex oligomers on the plasma membrane, but the EGF binding induced a local geometric rearrangement of these receptors such that the intracellular tyrosine kinase domains could more readily cross‐phosphorylate each other . Hence, the enhanced PLA signal following EGF binding most likely reflects this local rearrangement in the pre‐existing EGF‐receptor clusters, rather than ligand‐induced receptor dimerization.…”

SNARE Complex Alters the Interactions of the Ca2+sensor Synaptotagmin 1 with Lipid Bilayers

“…To elucidate the atomistic detail of Syt1 interations with the SNARE-Cpx complex and lipid bilayers, we performed all-atom molecular dynamics (MD) simulations at a microsecond scale. We took advantage of unique capabilities of the specialized Anton supercomputer designed for MD simulations [43,44], which enabled a breakthrough in simulating the protein dynamics at a time scale of microseconds [45,46]. We have recently employed these computational tools to investigate the conformational dynamics of Syt1 in the solution [47,48].…”