Sci. STKE, 21 May 2002
Development The Fate of Wnt Signaling
The Wnt family of secreted proteins regulates various cellular processes through cell surface receptors of the Frizzled family. The best understood canonical Wnt-Frizzled pathway induces the translocation of cytosolic β-catenin to the nucleus to regulate gene expression. However, less is known about an alternative non-canonical Wnt pathway that involves an increase in intracellular calcium. Saneyoshi et al. demonstrate that in early Xenopus embryos, a transcription factor previously implicated in immune cell regulation called nuclear factor of activated T cells (NF-AT), is activated by the Wnt-calcium pathway. Activation of this noncanonical pathway caused translocation of NF-AT to the nucleus in embryonic cells. Inhibition of this pathway perturbed cell movement during gastrulation, altering ventral side formation by promoting a dorsal fate instead. NF-AT was also dephosphorylated by the phosphastase calcineurin in response to a rise in intracellular calcium. By showing that NFAT inhibits the canonical Wnt pathway upstream of β-catenin, the authors suggest that cross talk between the two Wnt signaling cascades may be necessary for establishing dorsal-ventral polarity of the developing embryo.
T. Saneyoshi, S. Kume, Y. Amasaki, K. Mikoshiba, The Wnt/calcium pathway activates NF-AT and promotes ventral cell fate in Xenopus embryos. Nature 417, 295-299 (2002). [Online Journal]
Citation: The Fate of Wnt Signaling. Sci. STKE 2002, tw186 (2002).
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