Non‐canonical Wnt signaling regulates the stability of xSyndecan4

The non‐canonical or beta‐catenin independent Wnt signaling pathway regulates convergence and extension movements in vertebrate embryos and planar cell polarity. Recently in our laboratory, we have demonstrated that a cell surface heparan sulphate proteoglycan, Syndecan4 (xSyn4), is critical for Xenopus laevis gastrulation and is a component of the non‐canonical Wnt signalling pathway. We have found that xSyn4 is expressed in the same tissues and interacts functionally and biochemically with Frizzled‐7 (xFz7) and Dishevelled (xDsh). Furthermore, xSyn4 is necessary and sufficient to activate translocation of xDsh to the plasma membrane. In this work we have used methodologies such as GST‐pulldown and immunoprecipitation in HEK293T cells in order to investigate the interaction between xSyn4, xDsh and xFz7. We have observed that xDsh and xFz7 interact with xSyn4 cytoplasmic domain. Also, we have found that xSyn4 stability is regulated by activation of the non‐canonical Wnt pathway and that the cytoplasmic domain is required for such effect. This work is supported by FONDECYT Post‐Doctoral Fellowship 3070015 to L.C. and the Center for Cell Regulation and Pathology (FONDAP).