One of the largest domain-motif interactomes in human involves PSD-95/Discs-large/ZO-1 (PDZ) domains. The framework for understanding the PDZ interactome is well established; however the functional dynamics associated with PDZ-ligand interactions are poorly understood. Here, we report a dual PDZ-binding mode that ascribes unique dynamic features to class III ligand recognition. The crystal structure revealed that the PDZ domain can recognize either of the carboxylate moieties (terminal or internal) present in the class III ligand and laid out the register rules responsible for the dual recognition. Variants of the ligand designed to retain one or the other carboxylate of the native sequence were sufficient for PDZ binding. The conformational dynamics of PDZ probed by NMR relaxation dispersion experiments demonstrated that the class III ligand is shuffling binding modes as it engages with the PDZ domain. Our mechanistic findings reveal yet another aspect of PDZ binding plasticity specific to class III ligands.

• Klíčová slova
• CPMG relaxation dispersion, Class III ligands, Dishevelled, NMR spectroscopy, PDZ binding plasticity, PDZ domain, Wnt signaling, X-ray crystallography, protein dynamics, protein-protein interactions,
• MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• ligandy MeSH
• molekulární modely MeSH
• PDZ domény * MeSH
• protein PSD-95 chemie   MeSH
• vazba proteinů MeSH
• vazebná místa MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• ligandy MeSH
• protein PSD-95 MeSH

Most of the structural proteins known today are composed of domains that carry their own functions while keeping their structural properties. It is supposed that such domains, when taken out of the context of the whole protein, can retain their original structure and function to a certain extent. Information on the specific functional and structural characteristics of individual domains in a new context of artificial fusion proteins may help to reveal the rules of internal and external domain communication. Moreover, this could also help explain the mechanism of such communication and address how the mutual allosteric effect plays a role in a such multi-domain protein system. The simple model system of the two-domain fusion protein investigated in this work consisted of a well-folded PDZ3 domain and an artificially designed small protein domain called Tryptophan Cage (TrpCage). Two fusion proteins with swapped domain order were designed to study their structural and functional features as well as their biophysical properties. The proteins composed of PDZ3 and TrpCage, both identical in amino acid sequence but different in composition (PDZ3-TrpCage, TrpCage-PDZ3), were studied using circualr dichroism (CD) spectrometry, analytical ultracentrifugation, and molecular dynamic simulations. The biophysical analysis uncovered different structural and denaturation properties of both studied proteins, revealing their different unfolding pathways and dynamics.

• Klíčová slova
• chimeras, fusion protein, protein domains, protein dynamic studies,
• MeSH
• PDZ domény * genetika   fyziologie   MeSH
• rekombinantní fúzní proteiny * chemie   genetika   metabolismus   MeSH
• sekvence aminokyselin MeSH
• simulace molekulární dynamiky MeSH
• tryptofan * chemie   genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• rekombinantní fúzní proteiny * MeSH
• tryptofan * MeSH

In mature neurons, postsynaptic N-methyl-D-aspartate receptors (NMDARs) are segregated into two populations, synaptic and extrasynaptic, which differ in localization, function, and associated intracellular cascades. These two pools are connected via lateral diffusion, and receptor exchange between them modulates synaptic NMDAR content. Here, we identify the phosphorylation of the PDZ-ligand of the GluN2B subunit of NMDARs (at S1480) as a critical determinant in dynamically controlling NMDAR synaptic content. We find that phosphorylation of GluN2B at S1480 maintains NMDARs at extrasynaptic membranes as part of a protein complex containing protein phosphatase 1 (PP1). Global activation of NMDARs leads to the activation of PP1, which mediates dephosphorylation of GluN2B at S1480 to promote an increase in synaptic NMDAR content. Thus, PP1-mediated dephosphorylation of the GluN2B PDZ-ligand modulates the synaptic expression of NMDARs in mature neurons in an activity-dependent manner, a process with profound consequences for synaptic and structural plasticity, metaplasticity, and synaptic neurotransmission.

• Klíčová slova
• GluN2B, NMDA receptors, NMDAR synaptic content, PP1, dephosphorylation, extrasynaptic NMDAR,
• MeSH
• fosforylace MeSH
• krysa rodu Rattus MeSH
• kultivované buňky MeSH
• ligandy MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• neurony metabolismus   MeSH
• PDZ domény MeSH
• potkani Sprague-Dawley MeSH
• proteinfosfatasa 1 metabolismus   MeSH
• receptory N-methyl-D-aspartátu genetika   metabolismus   MeSH
• synapse metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Názvy látek
• ligandy MeSH
• NR2B NMDA receptor MeSH Prohlížeč
• proteinfosfatasa 1 MeSH
• receptory N-methyl-D-aspartátu MeSH

Dishevelled (DVL) is the key component of the Wnt signaling pathway. Currently, DVL conformational dynamics under native conditions is unknown. To overcome this limitation, we develop the Fluorescein Arsenical Hairpin Binder- (FlAsH-) based FRET in vivo approach to study DVL conformation in living cells. Using this single-cell FRET approach, we demonstrate that (i) Wnt ligands induce open DVL conformation, (ii) DVL variants that are predominantly open, show more even subcellular localization and more efficient membrane recruitment by Frizzled (FZD) and (iii) Casein kinase 1 ɛ (CK1ɛ) has a key regulatory function in DVL conformational dynamics. In silico modeling and in vitro biophysical methods explain how CK1ɛ-specific phosphorylation events control DVL conformations via modulation of the PDZ domain and its interaction with DVL C-terminus. In summary, our study describes an experimental tool for DVL conformational sampling in living cells and elucidates the essential regulatory role of CK1ɛ in DVL conformational dynamics.

• MeSH
• analýza jednotlivých buněk metody   MeSH
• biosenzitivní techniky MeSH
• enzymatické testy metody   MeSH
• fluorescenční mikroskopie metody   MeSH
• fosforylace fyziologie   MeSH
• frizzled receptory metabolismus   MeSH
• genový knockout MeSH
• HEK293 buňky MeSH
• kaseinkinasa Iepsilon genetika   metabolismus   MeSH
• lidé MeSH
• mutageneze cílená MeSH
• oocyty MeSH
• PDZ domény fyziologie   MeSH
• protein dishevelled genetika   metabolismus   MeSH
• rezonanční přenos fluorescenční energie MeSH
• signální dráha Wnt fyziologie   MeSH
• simulace molekulární dynamiky MeSH
• Xenopus laevis MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DVL3 protein, human MeSH Prohlížeč
• frizzled receptory MeSH
• FZD6 protein, human MeSH Prohlížeč
• kaseinkinasa Iepsilon MeSH
• protein dishevelled MeSH