PDZ7 of glutamate receptor interacting protein binds to its target via a novel hydrophobic surface area.
Glutamate receptor interacting protein 1 (GRIP1) is a scaffold protein composed of seven PDZ (Postsynaptic synaptic density-95/Discs large/Zona occludens-1) domains. The protein plays important roles in the synaptic targeting of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. The interaction between GRIP1 PDZ7 and a Ras guanine nucleotide exchange factor, GRASP-1, regulates synaptic distribution of AMPA receptors. Here, we describe the three-dimensional structure of GRIP1 PDZ7 determined by NMR spectroscopy. GRIP1 PDZ7 contains a closed carboxyl group-binding pocket and a narrow alphaB/betaB-groove that is not likely to bind to classical PDZ ligands. Unexpectedly, GRIP1 PDZ7 contains a large solvent-exposed hydrophobic surface at a site distinct from the conventional ligand-binding alphaB/betaB-groove. NMR titration experiments show that GRIP1 PDZ7 binds to GRASP-1 via this hydrophobic surface. Our data uncover a novel PDZ domain-mediated protein interaction mode that may be responsible for multimerization of other PDZ domain-containing scaffold proteins.
Feng
Wei
W
Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China.
Fan
Jing-Song
JS
Jiang
Ming
M
Shi
Ya-Wei
YW
Zhang
Mingjie
M
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019906:Nuclear Magnetic Resonance, Biomolecular; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats; D017386:Sequence Homology, Amino Acid
D002352:Carrier Proteins; C491308:Grip1 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins