Soluble frizzled-related proteins (sFRPS) function as modulators of Wnt signaling through direct interaction with Wnts. They have a role in regulating cell growth and differentiation in specific cell types. SFRP5 may be involved in determining the polarity of photoreceptor, and perhaps, other cells in the retina. Highly expressed in the retinal pigment epithelium (RPE) and pancreas. Weak expression in heart, liver and muscle. The FZ domain is involved in binding with Wnt ligands. Belongs to the secreted frizzled-related protein (sFRP) family.