Disheveled regulates precoupling of heterotrimeric G proteins to Frizzled 6

FASEB J. 2014 May;28(5):2293-305. doi: 10.1096/fj.13-246363. Epub 2014 Feb 5.


Frizzleds (FZDs) are classified as G-protein-coupling receptors, but how signals are initiated and specified through heterotrimeric G proteins is unknown. FZD6 regulates convergent extension movements, and its C-terminal Arg511Cys mutation causes nail dysplasia in humans. We investigated the functional relationship between FZD6, Disheveled (DVL), and heterotrimeric G proteins. Live cell imaging combined with fluorescence recovery after photobleaching (FRAP) revealed that inactive human FZD6 precouples to Gαi1 and Gαq but not to GαoA,Gαs, and Gα12 proteins. G-protein coupling is measured as a 10-20% reduction in the mobile fraction of fluorescently tagged G proteins on chemical receptor surface cross-linking. The FZD6 Arg511Cys mutation is incapable of G-protein precoupling, even though it still binds DVL. Using both FRAP and Förster resonance energy transfer (FRET) technology, we showed that the FZD6-Gαi1 and FZD-Gαq complexes dissociate on WNT-5A stimulation. Most important, G-protein precoupling of FZD6 and WNT-5A-induced signaling to extracellular signal-regulated kinase1/2 were impaired by DVL knockdown or overexpression, arguing for a strict dependence of FZD6-G-protein coupling on DVL levels and identifying DVL as a master regulator of FZD/G-protein signaling. In summary, we propose a mechanistic connection between DVL and G proteins integrating WNT, FZD, G-protein, and DVL function.

Keywords: GNAI1; GNAQ; GPCR; WNT-5A.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Membrane / metabolism
  • Dishevelled Proteins
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Fluorescence Recovery After Photobleaching
  • Fluorescence Resonance Energy Transfer
  • Frizzled Receptors / metabolism*
  • Green Fluorescent Proteins / metabolism
  • HEK293 Cells
  • Heterotrimeric GTP-Binding Proteins / metabolism*
  • Humans
  • Mutation
  • Phosphoproteins / metabolism*
  • Protein Binding
  • Proto-Oncogene Proteins / metabolism
  • Wnt Proteins / metabolism
  • Wnt-5a Protein


  • Adaptor Proteins, Signal Transducing
  • Dishevelled Proteins
  • FZD6 protein, human
  • Frizzled Receptors
  • Phosphoproteins
  • Proto-Oncogene Proteins
  • WNT5A protein, human
  • Wnt Proteins
  • Wnt-5a Protein
  • Green Fluorescent Proteins
  • Extracellular Signal-Regulated MAP Kinases
  • Heterotrimeric GTP-Binding Proteins