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Protein tyrosine kinase 7 has a conserved role in Wnt/β-catenin canonical signalling

Francesca Puppo1, Virginie Thomé, Anne-Catherine Lhoumeau

  • 1Inserm, U891, Centre de Recherche en Cancérologie de Marseille, 27 Boulevard Lei Roure, Marseille F-13009.

EMBO Reports
|December 7, 2010
PubMed

Insights

Receptor protein tyrosine kinase 7 (PTK7) interacts with β-catenin, revealing a novel role in Wnt canonical signaling. This discovery impacts understanding of embryonic development and Wnt pathway regulation.

Area of Science:

  • Molecular Biology
  • Developmental Biology
  • Cell Signaling

Background:

  • Receptor protein tyrosine kinase 7 (PTK7) has been implicated in noncanonical Wnt/planar cell polarity signaling.
  • The precise role of PTK7 in canonical Wnt signaling pathways remains largely unexplored.

Purpose of the Study:

  • To investigate the interaction between PTK7 and β-catenin.
  • To elucidate the function of PTK7 in canonical Wnt signaling and embryonic development.

Main Methods:

  • Yeast two-hybrid assays to detect protein interactions.
  • Mammalian cell culture and PTK7-deficient cell analysis.
  • Wnt3a stimulation and T-cell factor transcriptional activity assays.
  • Epistatic assays to determine signaling pathway order.

Main Results:

  • PTK7 directly interacts with β-catenin in both yeast and mammalian cells.
  • PTK7 deficiency leads to reduced β-catenin/T-cell factor transcriptional activity upon Wnt3a stimulation.
  • Xenopus PTK7 is essential for Spemann's organizer formation and Siamois promoter activation.
  • PTK7 functions upstream of glycogen synthase kinase 3 in the Wnt pathway.

Conclusions:

  • PTK7 plays a conserved and previously unrecognized role in the Wnt canonical signaling pathway.
  • PTK7's interaction with β-catenin is critical for Wnt-mediated transcriptional activity and embryonic patterning.

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