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Updated: Jun 28, 2026
Dissection of Xenopus laevis Neural Crest for in vitro Explant Culture or in vivo Transplantation
Published on: March 4, 2014
PTK7 recruits dsh to regulate neural crest migration
Iryna Shnitsar1, Annette Borchers
1Department of Developmental Biochemistry, Center for Molecular Physiology of the Brain (CMPB 37077 Goettingen, Germany.
Abstract:
PTK7 regulates planar cell polarity (PCP) signaling during vertebrate neural tube closure and establishment of inner ear hair cell polarity; however, its signaling mechanism is unknown. Here, we demonstrate a new function for PTK7 in Xenopus neural crest migration and use this system in combination with in vitro assays to define the intersection of PTK7 with the non-canonical Wnt signaling pathway that regulates PCP. In vitro, using Xenopus ectodermal explants, we show that PTK7 recruits dishevelled (dsh) to the plasma membrane, a function that is dependent on the PDZ domain of dsh, as well as on the conserved kinase domain of PTK7. Furthermore, endogenous PTK7 is required for frizzled7-mediated dsh localization. Immunoprecipitation experiments confirm that PTK7 can be found in a complex with dsh and frizzled7, suggesting that it cooperates with frizzled to localize dsh. To evaluate the in vivo relevance of the PTK7-mediated dsh localization, we analyzed Xenopus neural crest migration, as loss-of-function of PTK7 inhibits neural crest migration in whole embryos as well as in transplanted neural crest cells. Supporting the in vivo role of PTK7 in the localization of dsh, a PTK7 deletion construct deficient in dsh binding inhibits neural crest migration. Furthermore, the PTK7-mediated membrane localization of a dsh deletion mutant lacking PCP activity inhibits neural crest migration. Thus, PTK7 regulates neural crest migration by recruiting dsh, providing molecular evidence of how PTK7 intersects with the PCP signaling pathway to regulate vertebrate cell movements.
Insights
Protein tyrosine kinase 7 (PTK7) recruits dishevelled (dsh) to the plasma membrane, a key step in planar cell polarity (PCP) signaling. This mechanism is crucial for Xenopus neural crest cell migration and vertebrate development.
Area of Science:
- Cell Biology
- Developmental Biology
- Molecular Signaling
Background:
- Protein tyrosine kinase 7 (PTK7) is known to regulate planar cell polarity (PCP) signaling in vertebrates.
- The precise molecular mechanism by which PTK7 functions in PCP signaling remains largely unknown.
- PTK7's role in cellular processes beyond neural tube and inner ear development requires further elucidation.
Purpose of the Study:
- To investigate the signaling mechanism of PTK7 in the context of Xenopus neural crest cell migration.
- To define the intersection of PTK7 with the non-canonical Wnt signaling pathway that governs PCP.
- To elucidate how PTK7 regulates cell movements during vertebrate development.
Main Methods:
- Utilized Xenopus ectodermal explants for in vitro assays to study PTK7-dishevelled (dsh) interactions.
- Employed immunoprecipitation experiments to confirm protein complex formation.
- Analyzed Xenopus embryos and transplanted neural crest cells to assess in vivo PTK7 function in migration.
Main Results:
- Demonstrated that PTK7 recruits dishevelled (dsh) to the plasma membrane in a manner dependent on dsh's PDZ domain and PTK7's kinase domain.
- Showed that endogenous PTK7 is essential for frizzled7-mediated dsh localization and forms a complex with dsh and frizzled7.
- Confirmed that PTK7 loss-of-function and specific PTK7/dsh mutants inhibit Xenopus neural crest cell migration in vivo.
Conclusions:
- PTK7 plays a critical role in regulating Xenopus neural crest cell migration by recruiting dsh to the cell membrane.
- Established a molecular link between PTK7 and the PCP pathway, specifically through dsh localization.
- Provided evidence for PTK7's function in coordinating cell movements essential for vertebrate development.
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