Wnt Signaling Pathway
The Wnt pathway involves a large number of proteins which regulate cell-to-cell interactions during embryogenesis and cancer. The signal initiates when Wnt proteins bind to Frizzled receptors on the cell surface. The signal then is transduced to beta-catenin and enters the nucleus to form a complex to activate transcripThe Wnt signaling pathway is a signal transduction cascade that plays a pivotal role in numerous biological processes, including stem cell differentiation, axon guidance, and malignant transformation. Canonical Wnt signaling involves binding of Wnt proteins to Frizzled family receptors on the cell surface, which leads to activation of Dishevelled family proteins. This activation prevents the degradation of β-catenin, leading to its accumulation in the cytoplasm. The cytoplasmic accumulation and stabilization of β-catenin allow some β-catenin molecules to enter the nucleus where they interact with TCF/LEF family transcription factors and alter gene expression patterns. In addition to the canonical Wnt pathway, two non-canonical pathways have been well described, namely the planar cell polarity pathway and the Wnt/calcium pathway. These two pathways differ from the canonical pathway in various ways, including the ligands that activate each. Wnt proteins play important roles in the normal physiology of adult tissues and aberrant Wnt signaling can lead to many known human diseases, including Familial Exudative Vitreoretinopathy, Tetra-amelia, and colon cancer.
1.Logan CY and Nusse R. 2004. The Wnt signaling pathway in development and disease. Annu Rev Cell Dev Biol.20:781-810.