SFRP1 (D5A7) Rabbit mAb #3534

Secreted Frizzled-related proteins (SFRPs) display homology and structural similarity to the extracellular cysteine-rich Wnt-binding domain of the G protein-coupled receptor Frizzled (1,2). To date, five distinct SFRPs (SFRP1 to 5) have been found in mammalian cells. These secreted proteins typically act as antagonists to Wnt signaling by directly binding and inhibiting Wnt proteins, or by binding Frizzled to block Wnt protein interaction with the receptor (3). The various SFRPs bind and regulate Wnt proteins differentially; these proteins also display distinct expression patterns as they play important roles in regulating development (4-7). SFRP proteins appear to act as tumor suppressors, with loss of expression or function correlating with many invasive forms of cancer. Deletion of the corresponding SFRP1 gene and promoter hypermethylation leading to gene silencing has been reported in a number of cancers. Abnormal expression of SRFP1 and other Wnt signaling proteins is associated with some cases of retinitis pigmentosa (reviewed in 8).