Frizzled Receptors/metabolism; Receptors, G-Protein-Coupled/metabolism; Syntenins/metabolism; Wnt Proteins/metabolism; Amino Acid Sequence; Animals; Base Sequence; Binding Sites; Cells, Cultured; DNA, Complementary/genetics; Female; Frizzled Receptors/chemistry; Frizzled Receptors/genetics; Gene Expression Regulation, Developmental; Humans; Models, Biological; Molecular Sequence Data; Mutagenesis, Site-Directed; Phosphorylation; Protein Structure, Tertiary; Proto-Oncogene Proteins c-jun/metabolism; Receptors, G-Protein-Coupled/chemistry; Receptors, G-Protein-Coupled/genetics; Recombinant Proteins/chemistry; Recombinant Proteins/genetics; Recombinant Proteins/metabolism; STAT1 Transcription Factor; Sequence Homology, Amino Acid; Surface Plasmon Resonance; Syndecans/genetics; Syndecans/metabolism; Syntenins/chemistry; Syntenins/genetics; Xenopus Proteins/chemistry; Xenopus Proteins/genetics; Xenopus Proteins/metabolism; Xenopus laevis