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Disheveled regulates precoupling of heterotrimeric G proteins to Frizzled 6
Author(s) -
Kilander Michaela B. C.,
Petersen Julian,
Andressen Kjetil Wessel,
Ganji Ranjani Sri,
Levy Finn Olav,
Schuster Jens,
Dahl Niklas,
Bryja Vitezslav,
Schulte Gunnar
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.13-246363
Subject(s) - heterotrimeric g protein , frizzled , microbiology and biotechnology , biology , computational biology , g protein , signal transduction , wnt signaling pathway
Frizzleds (FZDs) are classified as G‐protein‐coupling receptors, but how signals are initiated and specified through heterotrimeric G proteins is unknown. FZD 6 regulates convergent extension movements, and its C‐terminal Arg511Cys mutation causes nail dysplasia in humans. We investigated the functional relationship between FZD 6 , Disheveled (DVL), and heterotrimeric G proteins. Live cell imaging combined with fluorescence recovery after photobleaching (FRAP) revealed that inactive human FZD 6 precouples to Gα i1 and Gα q but not to Gα oA ,Gα s , and Gα 12 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 FZD 6 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 FZD 6 ‐Gα i1 and FZD‐Gα q complexes dissociate on WNT‐5A stimulation. Most important, G‐protein precoupling of FZD 6 and WNT‐5A‐induced signaling to extracellular signal‐regulated kinase1/2 were impaired by DVL knockdown or overexpression, arguing for a strict dependence of FZD 6 ‐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.—Kilander, M. B. C., Petersen, J., Andressen, K. W., Ganji, R. S. Levy, F. O., Schuster, J., Dahl N., Bryja, V., Schulte, G. Disheveled regulates precoupling of heterotrimeric G proteins to Frizzled 6. FASEB J . 28, 2293–2305 (2014). www.fasebj.org