Signal transduction
Signal transduction: "Xenopus" embryos and cell-free extracts are widely used for basic research in signal transduction. In just the last few years, "Xenopus" embryos have provided crucial insights into the mechanisms of TGF-beta and Wnt signal transduction. For example, "Xenopus" embryos were used to identify the enzymes that control ubiquitination of Smad4, and to demonstrate direct links between TGF-beta superfamily signaling pathways and other important networks, such as the MAP kinase pathway and the Wnt pathway. Moreover, new methods using egg extracts revealed novel, important targets of the Wnt/GSK3 destruction complex.