GRASP (GRP1-associated scaffold protein, tamalin) is a 395 amino acid protein encoded by the human gene GRASP . GRASP is a scaffold protein that com- prises multiple protein-interacting domains, including a 95 kDa postsynaptic density protein (PSD-95)/discs-large/ZO-1 (PDZ) domain, a leucine-zipper region and a carboxyl-terminal PDZ-binding motif. GRASP is involved with intracellular trafficking and contributes to the macromolecular organization of group 1 metabotropic glutamate receptors (mGluRs) at synapses. GRASP forms a heteromer composed of GRASP , PSCD2 and at least one mGluR-1. It also interacts with PSCD3, mGluR-2, mGluR-3 and mGluR-5. GRASP is highly expressed in brain and has lower levels of expression in lung, heart, embryo, kidney and ovary.