Non-canonical Wnt signaling in Xenopus: regulation of axis formation and gastrulation.

Wnt proteins form a family of secreted glycoproteins that are involved in different developmental processes such as differentiation, proliferation, cell migration and cell polarity. To exert its function, Wnt proteins activate different intracellular signaling cascades. Whereas the canonical, Wnt/beta-catenin pathway is well characterized, less is known about the function of non-canonical Wnt pathways in vertebrates. I here summarize recent findings implicating important roles for Wnt/Ca(2+) and Wnt/JNK signaling during different aspects of early Xenopus laevis development, namely axis formation and gastrulation movements.