TY - JOUR
T1 - Interaction partners of PSD-93 studied by X-ray crystallography and fluorescence polarization spectroscopy
AU - Fiorentini, Monica
AU - Bach, Anders
AU - Strømgaard, Kristian
AU - Kastrup, Jette S
AU - Gajhede, Michael
PY - 2013/4
Y1 - 2013/4
N2 - PSD-93 (chapsyn-110, DLG2) is a member of the family of membrane-associated guanylate kinase (MAGUK) proteins. The MAGUK proteins are involved in receptor localization and signalling pathways. The best characterized MAGUK protein, PSD-95, is known to be involved in NMDA receptor signalling via its PDZ domains. The PDZ domains of PSD-95 and PSD-93 are structurally very similar, but relatively little is known about the function of PSD-93. PSD-93 has been suggested to interact with GluD2 from the family of ionotropic glutamate receptors. Here, the interactions of four residues (GTSI) representing the extreme C-terminus of GluD2 with PSD-93 PDZ1 have been investigated in the crystalline phase. Two different binding modes of these residues were observed, suggesting that the peptide is not tightly bound to PSD-93 PDZ1. In accordance, the two N-terminal PSD-93 PDZ domains show no appreciable binding affinity for a GluD2-derived C-terminal octapeptide, whereas micromolar affinity was observed for a GluN2B-derived C-terminal octapeptide. This indicates that if present, the interactions between GluD2 and PSD-93 involve more than the extreme terminus of the receptor. In contrast, the tumour-suppressor protein SCRIB PDZ3 shows low micromolar affinity towards the GluD2-derived octapeptide, which is in agreement with previous findings using high-throughput assays.
AB - PSD-93 (chapsyn-110, DLG2) is a member of the family of membrane-associated guanylate kinase (MAGUK) proteins. The MAGUK proteins are involved in receptor localization and signalling pathways. The best characterized MAGUK protein, PSD-95, is known to be involved in NMDA receptor signalling via its PDZ domains. The PDZ domains of PSD-95 and PSD-93 are structurally very similar, but relatively little is known about the function of PSD-93. PSD-93 has been suggested to interact with GluD2 from the family of ionotropic glutamate receptors. Here, the interactions of four residues (GTSI) representing the extreme C-terminus of GluD2 with PSD-93 PDZ1 have been investigated in the crystalline phase. Two different binding modes of these residues were observed, suggesting that the peptide is not tightly bound to PSD-93 PDZ1. In accordance, the two N-terminal PSD-93 PDZ domains show no appreciable binding affinity for a GluD2-derived C-terminal octapeptide, whereas micromolar affinity was observed for a GluN2B-derived C-terminal octapeptide. This indicates that if present, the interactions between GluD2 and PSD-93 involve more than the extreme terminus of the receptor. In contrast, the tumour-suppressor protein SCRIB PDZ3 shows low micromolar affinity towards the GluD2-derived octapeptide, which is in agreement with previous findings using high-throughput assays.
KW - Cell Communication
KW - Crystallization
KW - Crystallography, X-Ray
KW - Fluorescence Polarization
KW - Guanylate Kinase
KW - Humans
KW - Microscopy, Fluorescence, Multiphoton
KW - Peptide Fragments
KW - Protein Interaction Mapping
KW - Protein Structure, Tertiary
KW - Spectrometry, Fluorescence
KW - Tumor Suppressor Proteins
U2 - 10.1107/s0907444912051839
DO - 10.1107/s0907444912051839
M3 - Journal article
C2 - 23519667
SN - 0907-4449
VL - 69
SP - 587
EP - 594
JO - Acta Crystallographica. Section D: Biological Crystallography
JF - Acta Crystallographica. Section D: Biological Crystallography
IS - Pt 4
ER -