Secreted Frizzled Related Protein 2 (SFRP2)

SFRP2 encodes a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of Frizzled proteins. The partial human SARP1 cDNA encodes a polypeptide that is 95% identical to mouse Sarp1. When expressed in a breast adenocarcinoma cell line, mouse SARP1 and human SARP2 exhibited opposite effects on cell sensitivity to proapoptotic stimuli. Whereas cells with SARP1 had higher resistance, cells expressing SARP2 were sensitized to apoptosis induced by tumor necrosis factor and ceramide. Expression of SARP1 or SARP2 modified the intracellular levels of beta-catenin, an indicator of Wnt-frizzled protein interaction and signal transduction, suggesting that SARPs interfere with the Wnt-frizzled signaling pathway.