ERBB4 can bind to a postsynaptic density (PSD) protein DLG4 (PSD-95) (Huang et al. 2000, Garcia et al. 2000). Binding to DLG4 enables ERBB4 to localize to the PSD, where it can modulate the activity of neurotransmitter receptors, but most ERBB4 receptors are found outside of the PSD in neuronal cells (Mitchell et al. 2013). One molecule of DLG4 can bind two molecules of ERBB4, which may facilitate ERBB4 dimerization upon ligand binding (Huang et al. 2000).