Wnt-5b is a 49 kDa glycoprotein of the subgroup of Wnts that is implicated in the non-canonical Wnt/Ca2+ pathway. Wnt-5b is not axis-inducing in Xenopus embryos and only weakly transforms C57MG mammary epithelial cells. In adult mice, Wnt-5b is expressed in heart, liver, brain, lung, testes, kidney, and pancreas. Wnt-5b appears to promote adipogenesis and is upregulated in early adipogenesis. Also, Wnt-5b overexpression in 3T3-L1 cells partially inhibits canonical Wnt suppression of adipogenesis.
Human Wnt-5b polymorphisms have been associated with Type II diabetes. Although Wnt-5a and Wnt-5b share 83% amino acid identity, they show differential expression and regulation of cyclin D1 and p130 during endochondral bone development. Together, Wnt-5a and Wnt-5b appear to coordinate chondrocyte proliferation and differentiation. The expression of Wnt-5a and Wnt-5b are also implicated in limb development. Mature mouse Wnt-5b shows 94%, 98%, 90% and 88% amino acid identity with mature human, rat, chick and Xenopus Wnt-5b, respectively.