title: PDZ domain-mediated interactions of G protein-coupled receptors with postsynaptic density protein 95: quantitative characterization of interactions.
abstract: G protein-coupled receptors (GPCRs) constitute the largest family of membrane proteins in the human genome. Their signaling is regulated by scaffold proteins containing PDZ domains, but although these interactions are important for GPCR function, they are still poorly understood. We here present a quantitative characterization of the kinetics and affinity of interactions between GPCRs and one of the best characterized PDZ scaffold proteins, postsynaptic density protein 95 (PSD-95), using fluorescence polarization (FP) and surface plasmon resonance (SPR). By comparing these in vitro findings with colocalization of the full-length proteins in cells and with previous studies, we suggest that the range of relevant interactions might extend to interactions with K i = 450 µM in the in vitro assays. Within this range, we identify novel PSD-95 interactions with the chemokine receptor CXCR2, the neuropeptide Y receptor Y2, and four of the somatostatin receptors (SSTRs). The interaction with SSTR1 was further investigated in mouse hippocampal neurons, where we found a clear colocalization between the endogenously expressed proteins, indicating a potential for further investigation of the role of this interaction. The approach can easily be transferred to other receptors and scaffold proteins and this could help accelerate the discovery and quantitative characterization of GPCR-PDZ interactions.
authors.affiliation: Department of Chemistry & Nano-Science Center, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thor C
authors.initials: TC
authors.lastname: Møller
authors.forename: Volker F
authors.initials: VF
authors.lastname: Wirth
authors.forename: Nina I
authors.initials: NI
authors.lastname: Roberts
authors.forename: Julia
authors.initials: J
authors.lastname: Bender
authors.forename: Anders
authors.initials: A
authors.lastname: Bach
authors.forename: Birgitte P S
authors.initials: BP
authors.lastname: Jacky
authors.forename: Kristian
authors.initials: K
authors.lastname: Strømgaard
authors.forename: Jan M
authors.initials: JM
authors.lastname: Deussing
authors.forename: Thue W
authors.initials: TW
authors.lastname: Schwartz
authors.forename: Karen L
authors.initials: KL
authors.lastname: Martinez
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000076122:Disks Large Homolog 4 Protein; D057809:HEK293 Cells; D006624:Hippocampus / Q000166:cytology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000378:metabolism; D054731:PDZ Domains; D057786:Peptidomimetics / Q000138:chemical synthesis / Q000378:metabolism; D011485:Protein Binding; D021381:Protein Transport; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry* / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: C501444:DLG4 protein, human; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D057786:Peptidomimetics; D043562:Receptors, G-Protein-Coupled