WNT5B is a ligand for members of the frizzled family of seven transmembrane receptors. Wnt proteins constitute a large family of secreted molecules that are involved in intercellular signalling during development and have been implicated in oncogenesis. Very little is known about the structure of Wnts as they are notoriously insoluble; but they share the following features characteristics of secretory proteins: a signal peptide, several potential N-glycosylation sites and 22 conserved cysteines. The Wnt proteins seem to adhere to the plasma membrane of the secreting cells and are therefore likely to signal over only few cell diameters. Fifteen major Wnt gene families have been identified in vertebrates, with multiple subtypes within some classes.