We report the cloning of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor-binding protein (ABP), a postsynaptic density (PSD) protein related to glutamate receptor-interacting protein (GRIP) with two sets of three PDZ domains, which binds the GluR2/3 AMPA receptor subunits. ABP exhibits widespread CNS expression and is found at the postsynaptic membrane. We show that the protein interactions of the ABP/GRIP family differ from the PSD-95 family, which binds N-methyl-D-aspartate (NMDA) receptors. ABP binds to the GluR2/3 C-terminal VKI-COOH motif via class II hydrophobic PDZ interactions, distinct from the class I PSD-95-NMDA receptor interaction. ABP and GRIP also form homo- and heteromultimers through PDZ-PDZ interactions but do not bind PSD-95. We suggest that the ABP/GRIP and PSD-95 families form distinct scaffolds that anchor, respectively, AMPA and NMDA receptors.
Srivastava, S., Osten, P., Vilim, F. S., Khatri, L., Inman, G., States, B., Daly, C., DeSouza, S., Abagyan, R., Valtschanoff, J. G., Weinberg, R. J., & Ziff, E. B. (1998). Novel anchorage of GluR2/3 to the postsynaptic density by the AMPA receptor-binding protein ABP. Neuron, 21(3), 581-591. https://doi.org/10.1016/S0896-6273(00)80568-1