| 1. |
- Kilander, Michaela B. C., et al.
(författare)
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Disheveled regulates precoupling of heterotrimeric G proteins to Frizzled 6
- 2014
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Ingår i: The FASEB Journal. - : Wiley. - 0892-6638 .- 1530-6860. ; 28:5, s. 2293-2305
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Tidskriftsartikel (refereegranskat)abstract
- 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 G(i1) and G(q) but not to G(oA),G(s), and G(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 Forster resonance energy transfer (FRET) technology, we showed that the FZD(6)-G(i1) and FZD-G(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.
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| 2. |
- Petersen, Julian, et al.
(författare)
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A previously uncharacterized Factor Associated with Metabolism and Energy (FAME/C14orf105/CCDC198/1700011H14Rik) is related to evolutionary adaptation, energy balance, and kidney physiology
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- In this study we use comparative genomics to uncover a gene with uncharacterized function (1700011H14Rik/C14orf105/CCDC198), which we hereby name FAME (Factor Associated with Metabolism and Energy). We observe that FAME shows an unusually high evolutionary divergence in birds and mammals. Through the comparison of single nucleotide polymorphisms, we identify gene flow of FAME from Neandertals into modern humans. We conduct knockout experiments on animals and observe altered body weight and decreased energy expenditure in Fame knockout animals, corresponding to genome-wide association studies linking FAME with higher body mass index in humans. Gene expression and subcellular localization analyses reveal that FAME is a membrane-bound protein enriched in the kidneys. Although the gene knockout results in structurally normal kidneys, we detect higher albumin in urine and lowered ferritin in the blood. Through experimental validation, we confirm interactions between FAME and ferritin and show co-localization in vesicular and plasma membranes.
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| 3. |
- Strakova, Katerina, et al.
(författare)
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Dishevelled enables casein kinase 1-mediated phosphorylation of Frizzled 6 required for cell membrane localization
- 2018
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Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 293:48, s. 18477-18493
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Tidskriftsartikel (refereegranskat)abstract
- Frizzleds (FZDs) are receptors for secreted lipoglycoproteins of the Wingless/Int-1(WNT) family, initiating an important signal transduction network in multicellular organisms. FZDs are G protein-coupled receptors (GPCRs), which are well known to be regulated by phosphorylation, leading to specific downstream signaling or receptor desensitization. The role and underlying mechanisms of FZD phosphorylation remain largely unexplored. Here, we investigated the phosphorylation of human FZD(6). Using MS analysis and a phospho-state- and -site-specific antibody, we found that Ser-648, located in the FZD(6) C terminus, is efficiently phosphorylated by casein kinase 1 is an element of (CK1 is an element of) and that this phosphorylation requires the scaffolding protein Dishevelled (DVL). In an overexpression system, DVL1, -2, and -3 promoted CK1-mediated FZD(6) phosphorylation on Ser-648. This DVL activity required an intact DEP domain and FZD-mediated recruitment of this domain to the cell membrane. Substitution of the CK1 is an element of-targeted phosphomo-tif reduced FZD(6) surface expression, suggesting that Ser-648 phosphorylation controls membrane trafficking of FZD(6). Phos-pho-Ser-648 FZD(6) immunoreactivity in human fallopian tube epithelium was predominantly apical, associated with cilia in a subset of epithelial cells, compared with the total FZD(6) protein expression, suggesting that FZD(6) phosphorylation contributes to asymmetric localization of receptor function within the cell and to epithelial polarity. Given the key role of FZD(6) in planar cell polarity, our results raise the possibility that asymmetric phosphorylation of FZD(6) rather than asymmetric protein distribution accounts for polarized receptor signaling.
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