Fz7-21 is a peptide identified from a phage library that impairs the function of Frizzled 7 (FZD7) in Wnt-beta-catenin signalling, binding to the FZD7 extracellular cysteine rich domain (CRD) and altering its conformation and the architecture of its lipid-binding groove. Fz7-21 antagonises Wnt-beta-catenin signaling in HEK293 cells stimulated with exogenous WNT3A with an IC50 of 100 nM and also blocks WNT3A-mediated stabilization of beta -catenin in mouse L cells. FzD7-21 impairs stem cell function in intestinal organoids.
