Wnt-8a is a secreted glycoprotein that binds to receptors of the Frizzled family. Wnt-8a is expressed during early optic lens development and cardiac myogenesis. The expression of Wnt-8a has also been shown to be upregulated during primitive hematopoiesis. TGF-beta has been shown to increase Wnt-8a secretion during epithelial mesenchymal transition (EMT).
The Wnts make up a large family of secreted proteins with roles in pattern formation, cell fate decision, axon guidance, and tumor formation. Wnt family members vary in length between 350 and 400 amino acids (aa), possess 22 to 24 conserved cysteines, are highly hydrophobic, and show 20 - 85% aa identity within the Wnt family. In general, there are three signaling pathways associated with Wnt-receptor interaction. The first is commonly called the canonical pathway and ultimately culminates in beta-Catenin accumulation and TCF/LEF-1-mediated gene transcription. The other two less well-defined non-canonical pathways include the Wnt/Ca2+ pathway and the planar cell polarity (PCP) pathway.