Intramolecular domain dynamics regulate synaptic MAGUK protein interactions.
PSD-95 MAGUK family scaffold proteins are multi-domain organisers of synaptic transmission that contain three PDZ domains followed by an SH3-GK domain tandem. This domain architecture allows coordinated assembly of protein complexes composed of neurotransmitter receptors, synaptic adhesion molecules and downstream signalling effectors. Here we show that binding of monomeric CRIPT-derived ... PDZ3 ligands to the third PDZ domain of PSD-95 induces functional changes in the intramolecular SH3-GK domain assembly that influence subsequent homotypic and heterotypic complex formation. We identify PSD-95 interactors that differentially bind to the SH3-GK domain tandem depending on its conformational state. Among these interactors, we further establish the heterotrimeric G protein subunit Gnb5 as a PSD-95 complex partner at dendritic spines of rat hippocampal neurons. The PSD-95 GK domain binds to Gnb5, and this interaction is triggered by CRIPT-derived PDZ3 ligands binding to the third PDZ domain of PSD-95, unraveling a hierarchical binding mechanism of PSD-95 complex formation.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Animals, COS Cells, Chlorocebus aethiops, Disks Large Homolog 4 Protein, GTP-Binding Protein beta Subunits, HEK293 Cells, Hippocampus, Humans, Protein Binding, Protein Conformation, Protein Domains, Protein Multimerization, Synapses
Adaptor Proteins, Signal Transducing, Animals, COS Cells, Chlorocebus aethiops, Disks Large Homolog 4 Protein, GTP-Binding Protein beta Subunits, HEK293 Cells, Hippocampus, Humans, Protein Binding, Protein Conformation, Protein Domains, Protein Multimerization, Synapses
Elife
Date: Dec. 13, 2018
PubMed ID: 30864948
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