ACTN2 (alpha-actinin-2) directly binds to GluN1 (GRIN1) subunit of the NMDA receptor, but can also bind to GluN2B (GRIN2B) (Wyszynski et al. 1997). Binding to ACTN2 anchors NMDA receptors to the actin cytoskeleton and is needed for the assembly of the postsynaptic density (Wyszynski et al. 1997, Hodges et al. 2014).