The Ins and Outs of EGFR Asymmetry

The epidermal growth factor receptor (EGFR) regulates cell proliferation in many tissues. A new structure of the Drosophila EGFR presented by Alvarado et al. (2010) reveals an asymmetric dimer with the ligand bound to only one subunit. The structure provides a rationale for the receptor's negative cooperativity and necessitates a reconsideration of models for activation of human EGFR.