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 FZD6 Using MS analysis and a phospho-state- and -site-specific antibody, we found that Ser-648, located in the FZD6 C terminus, is efficiently phosphorylated by casein kinase 1 ϵ (CK1ϵ) and that this phosphorylation requires the scaffolding protein Dishevelled (DVL). In an overexpression system, DVL1, -2, and -3 promoted CK1ϵ-mediated FZD6 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 CK1ϵ-targeted phosphomotif reduced FZD6 surface expression, suggesting that Ser-648 phosphorylation controls membrane trafficking of FZD6 Phospho-Ser-648 FZD6 immunoreactivity in human fallopian tube epithelium was predominantly apical, associated with cilia in a subset of epithelial cells, compared with the total FZD6 protein expression, suggesting that FZD6 phosphorylation contributes to asymmetric localization of receptor function within the cell and to epithelial polarity. Given the key role of FZD6 in planar cell polarity, our results raise the possibility that asymmetric phosphorylation of FZD6 rather than asymmetric protein distribution accounts for polarized receptor signaling.

• Klíčová slova
• Dishevelled, Frizzled, G protein-coupled receptor (GPCR), GRK, WNT, casein kinase 1, cell polarity, cell signaling, phosphorylation, receptor regulation, scaffold protein, serine/threonine protein kinase,
• MeSH
• buněčná membrána metabolismus   MeSH
• epitel metabolismus   MeSH
• fosfoproteiny imunologie   MeSH
• fosforylace MeSH
• frizzled receptory chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• hmotnostní spektrometrie MeSH
• kasein kinasa I metabolismus   MeSH
• lidé MeSH
• protein dishevelled chemie   fyziologie   MeSH
• protilátky imunologie   MeSH
• sekvence aminokyselin MeSH
• serin metabolismus   MeSH
• signální transdukce MeSH
• vejcovody metabolismus   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fosfoproteiny MeSH
• frizzled receptory MeSH
• FZD6 protein, human MeSH Prohlížeč
• kasein kinasa I MeSH
• protein dishevelled MeSH
• protilátky MeSH
• serin MeSH