In the context of cell signaling, Wnt proteins function mainly as what type of molecules?

Wnt proteins primarily function as ligands in cell signaling pathways. In cell signaling, ligands are molecules that bind to specific receptors and initiate a response within the cell. Wnt proteins are secreted glycoproteins that interact with frizzled receptors and co-receptors to activate various intracellular signaling cascades, such as the Wnt/β-catenin pathway. This pathway plays a crucial role in regulating cellular processes such as proliferation, differentiation, and embryonic development.

By acting as ligands, Wnt proteins are critical in mediating development and maintaining stem cell populations. Their binding to receptors leads to a series of downstream effects, influencing diverse biological processes. Thus, identifying Wnt proteins as ligands highlights their essential role in initiating and modulating signaling events necessary for proper cellular functions.