Commercially Available Preparations of Recombinant Wnt3a Contain Non-Wnt Related Activities Which May Activate TGF-β Signaling.

Jon M Carthy, Ulla Engström, Carl-Henrik Heldin, Aristidis Moustakas

Index: J. Cell. Biochem. 117 , 938-45, (2016)

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Abstract

The Wnt ligands are a family of secreted signaling proteins which play key roles in a number of cellular processes under physiological and pathological conditions. Wnts bind to their membrane receptors and initiate a signaling cascade which leads to the nuclear localization and transcriptional activity of β-catenin. The development of purified recombinant Wnt ligands has greatly aided in our understanding of Wnt signaling and its functions in development and disease. In the current study, we identified non-Wnt related signaling activities which were present in commercially available preparations of recombinant Wnt3a. Specifically, we found that treatment of cultured fibroblasts with recombinant Wnt3a induced immediate activation of TGF-β and BMP signaling and this activity appeared to be independent of the Wnt ligand itself. Therefore, while purified recombinant Wnt ligands continue to be a useful tool for studying this signaling pathway, one must exercise a degree of caution when analyzing the results of experiments that utilize purified recombinant Wnt ligands.© 2015 Wiley Periodicals, Inc.