Abstract
The receptor protein tyrosine kinase 7 (PTK7) was recently shown to participate in noncanonical Wnt/planar cell polarity signalling during mouse and frog embryonic development. In this study, we report that PTK7 interacts with β-catenin in a yeast two-hybrid assay and mammalian cells. PTK7-deficient cells exhibit weakened β-catenin/T-cell factor transcriptional activity on Wnt3a stimulation. Furthermore, Xenopus PTK7 is required for the formation of Spemann's organizer and for Siamois promoter activation, events that require β-catenin transcriptional activity. Using epistatic assays, we demonstrate that PTK7 functions upstream from glycogen synthase kinase 3. Taken together, our data reveal a new and conserved role for PTK7 in the Wnt canonical signalling pathway.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Adhesion Molecules / physiology
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Embryo, Mammalian
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Embryo, Nonmammalian
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Glycogen Synthase Kinase 3 / metabolism
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Homeodomain Proteins / metabolism
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Humans
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Mice
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Mice, Knockout
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Organizers, Embryonic / metabolism
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Receptor Protein-Tyrosine Kinases / genetics
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Receptor Protein-Tyrosine Kinases / physiology*
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Signal Transduction
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Two-Hybrid System Techniques
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Wnt Proteins / metabolism*
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Xenopus Proteins / metabolism
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Xenopus laevis
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beta Catenin / metabolism*
Substances
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Cell Adhesion Molecules
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Homeodomain Proteins
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SIA1 protein, Xenopus
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Wnt Proteins
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Xenopus Proteins
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beta Catenin
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PTK7 protein, Xenopus
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PTK7 protein, human
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Ptk7 protein, mouse
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Receptor Protein-Tyrosine Kinases
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Glycogen Synthase Kinase 3