Abstract
PDZ domains typically interact with the very carboxyl terminus of their binding partners. Type 1 PDZ domains usually require valine, leucine, or isoleucine at the very COOH-terminal (P(0)) position, and serine or threonine 2 residues upstream at P(-2). We quantitatively defined the contributions of carboxyl-terminal residues to binding selectivity of the prototypic interactions of the PDZ domains of postsynaptic density protein 95 (PSD-95) and its homolog synapse-associated protein 90 (SAP102) with the NR2b subunit of the N-methyl-d-aspartate-type glutamate receptor. Our studies indicate that all of the last five residues of NR2b contribute to the binding selectivity. Prominent were a requirement for glutamate or glutamine at P(-3) and for valine at P(0) for high affinity binding and a preference for threonine over serine at P(-2), in the context of the last 11 residues of the NR2b COOH terminus. This analysis predicts a COOH-terminal (E/Q)(S/T)XV consensus sequence for the strongest binding to the first two PDZ domains of PSD-95 and SAP102. A search of the human genome sequences for proteins with a COOH-terminal (E/Q)(S/T)XV motif yielded 50 proteins, many of which have not been previously identified as PSD-95 or SAP102 binding partners. Two of these proteins, brain-specific angiogenesis inhibitor 1 and protein kinase Calpha, co-immunoprecipitated with PSD-95 and SAP102 from rat brain extracts.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Angiogenesis Inhibitors
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Angiogenic Proteins*
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Animals
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Anisotropy
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Brain / metabolism
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Disks Large Homolog 4 Protein
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Dose-Response Relationship, Drug
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Frizzled Receptors
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Genome, Human
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Glutathione Transferase / metabolism
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Humans
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Immunoblotting
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Intracellular Signaling Peptides and Proteins
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Isoenzymes / chemistry
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Kinetics
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Membrane Proteins
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Models, Molecular
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Molecular Sequence Data
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Nerve Tissue Proteins / chemistry*
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Neuropeptides / chemistry*
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Nuclear Proteins*
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Peptides / chemistry
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Precipitin Tests
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Protein Binding
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Protein Kinase C / chemistry
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Protein Kinase C-alpha
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Protein Structure, Tertiary
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Proteins / chemistry
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Rats
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Receptors, G-Protein-Coupled
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Receptors, Neurotransmitter / chemistry
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Recombinant Fusion Proteins / metabolism
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Sequence Homology, Amino Acid
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Serine / chemistry
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Spectrometry, Fluorescence
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Threonine / chemistry
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Transcription Factors*
Substances
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ADGRB1 protein, human
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Angiogenesis Inhibitors
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Angiogenic Proteins
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DLG3 protein, human
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Disks Large Homolog 4 Protein
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Dlg3 protein, rat
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Dlg4 protein, rat
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FZD2 protein, human
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Frizzled Receptors
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Intracellular Signaling Peptides and Proteins
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Isoenzymes
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Membrane Proteins
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Nerve Tissue Proteins
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Neuropeptides
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Nuclear Proteins
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Peptides
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Proteins
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Receptors, G-Protein-Coupled
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Receptors, Neurotransmitter
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Recombinant Fusion Proteins
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Transcription Factors
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postsynaptic density proteins
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Fzd2 protein, rat
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Threonine
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Serine
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Glutathione Transferase
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PRKCA protein, human
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Protein Kinase C
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Protein Kinase C-alpha