a, Representative micrograph of the HER2/HER3/NRG1β sample on graphene oxide grids, from a dataset with 2035 GO-containing micrographs. The scale bar corresponds to 0.5 μm. b, Example 2D cryo-EM class averages. c, Local resolution estimation from ResMap. d, Gold Standard Fourier Shell Correlation (GSFSC) of the final map used for model building from CryoSPARC2 with a reported resolution of 2.93 Å. e, Directional FSCs calculated by 3DFSC server. Map sphericity was calculated to be 0.927. f, Workflow for processing the HER2/HER3/NRG1β dataset. Blue box indicates model and associated particle stack used for downstream processing. The final model is indicated with a red box. The map in the yellow box represents a slightly different low-occupancy species. The insets show that the HER3 dimerization arm is still poorly resolved in that class.