G protein-coupled receptors (GPCRs) constitute the largest family of cell surface receptors. They can exist and act as dimers, but the requirement of dimers for agonist-induced signal initiation and structural dynamics remains largely unknown. Frizzled 6 (FZD6) is a member of Class F GPCRs, which bind WNT proteins to initiate signaling. Here, we show that FZD6 dimerizes and that the dimer interface of FZD6 is formed by the transmembrane α-helices four and five. Most importantly, we present the agonist-induced dissociation/re-association of a GPCR dimer through the use of live cell imaging techniques. Further analysis of a dimerization-impaired FZD6 mutant indicates that dimer dissociation is an integral part of FZD6 signaling to extracellular signal-regulated kinases1/2. The discovery of agonist-dependent dynamics of dimers as an intrinsic process of receptor activation extends our understanding of Class F and other dimerizing GPCRs, offering novel targets for dimer-interfering small molecules.Frizzled 6 (FZD6) is a G protein-coupled receptor (GPCR) involved in several cellular processes. Here, the authors use live cell imaging and spectroscopy to show that FZD6 forms dimers, whose association is regulated by WNT proteins and that dimer dissociation is crucial for FZD6 signaling.

• MeSH
• dimerizace MeSH
• frizzled receptory metabolismus   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• protein Wnt 5a metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Frizzleds (FZDs) are unconventional G protein-coupled receptors, which activate diverse intracellular signaling pathways via the phosphoprotein Disheveled (DVL) and heterotrimeric G proteins. The interaction interplay of FZDs with DVL and G proteins is complex, involves different regions of FZD and the potential dynamics are poorly understood. In the present study, we aimed to characterize the function of a highly conserved tyrosine (Y2502.39) in the intracellular loop 1 (IL1) of human FZD4. We have found Y2502.39 to be crucial for DVL2 interaction and DVL2 translocation to the plasma membrane. Mutant FZD4-Y2502.39F, impaired in DVL2 binding, was defective in both β-catenin-dependent and β-catenin-independent WNT signaling induced in Xenopus laevis embryos. The same mutant maintained interaction with the heterotrimeric G proteins Gα12 and Gα13 and was able to mediate WNT-induced G protein dissociation and G protein-dependent YAP/TAZ signaling. We conclude from modeling and dynamics simulation efforts that Y2502.39 is important for the structural integrity of the FZD-DVL, but not for the FZD-G protein interface and hypothesize that the interaction network of Y2502.39 and H3484.46 plays a role in specifying downstream signaling pathways induced by the receptor.

• MeSH
• aminokyselinové motivy MeSH
• embryo nesavčí metabolismus   MeSH
• frizzled receptory chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• heterotrimerní G-proteiny metabolismus   MeSH
• konzervovaná sekvence * MeSH
• lidé MeSH
• mutační analýza DNA MeSH
• nádory metabolismus   patologie   MeSH
• polymerizace MeSH
• protein dishevelled chemie   metabolismus   MeSH
• sekvence aminokyselin MeSH
• signální dráha Wnt MeSH
• signální transdukce MeSH
• simulace molekulární dynamiky MeSH
• strukturní homologie proteinů MeSH
• tyrosin metabolismus   MeSH
• vazba proteinů MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Xenopus laevis embryologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH