R-Spondin 1 Proteins and Enzymes

R-Spondin 1 (RSPO1), also known as Cristin 3, is a 27 kDa secreted protein in the R-Spondin family of Wnt/beta-catenin signaling regulators. R-Spondin 1 enhances canonical Wnt/beta-catenin signaling by competing with the Wnt antagonist Dkk-1, binding to Frizzled-8, Kremen, LRP-6, Lgr4, Lgr5, and Lgr6, and enhancing cell surface availability of Wnt receptors. R-Spondin 1 functions in dorsal neural tube development as well as male and female germ cell development. It also induces bone formation, intestinal crypt cell proliferation, angiogenesis, and insulin secretion from pancreatic beta cells.