Wnt Signaling: Multiple Pathways, Multiple Receptors, and Multiple Transcription Factors

Signaling pathways are an ever present force in every animal’s life. During development, these pathways provide critical cell-cell communication required to coordinate the activities of vast numbers of cells. In adulthood, similar communication mechanisms are utilized to achieve tissue homeostasis and regeneration. Regulation of signaling is crucial; too much or too little activity from a given signal transduction pathway can cause devastating results such as developmental defects or, later in life, disease. The Wnts comprise a large family of highly conserved growth factors that are responsible for important developmental and homeostatic processes throughout the animal kingdom (for a more comprehensive review see Ref. 1). Their implication in a wide array of developmental events and human diseases has made Wnts and their signaling pathways the subject of intense investigation