FRP-3 (secreted)

Secreted Frizzled Related Protein‑3 (sFRP‑3), also known as FRZB, belongs to a family of Wnt-binding proteins with homology to the ligand‑binding domain of the Frizzled receptors. sFRPs are approximately 30‑35 kDa in size and contain an N‑terminal Frizzled‑like domain with 10 conserved cysteines and a Netrin-like C‑terminal domain. Mature human sFRP‑3 shares 93% aa sequence identity with mouse and rat sFRP‑3. It neutralizes the bioactivity of Wnt‑1, ‑5a, ‑9a, Xenopus Xwnt‑8, and EGF (5‑8) . sFRP‑3 regulates somitic myogenesis and osteoblast differentiation as well as morphogenesis of the cochlear epithelium, hair follicle, and cardiac atrioventricular cushion. sFRP‑3 also functions as a tumor suppressor in a variety of cancers including melanoma, medulloblastoma, soft tissue sarcoma, and androgen‑independent prostate cancer. It inhibits epithelial-mesenchymal transition, tumor growth and invasion, and the activity of MMP‑2 and MMP‑9. In contrast, it can promote tumor growth and angiogenesis in renal cancer.