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. SFRP1 decreases intracellular beta-catenin levels (By similarity). Has antiproliferative effects on vascular cells, in vitro and in vivo, and can induce, in vivo, an angiogenic response. In vascular cell cycle, delays the G1 phase and entry into the S phase. In kidney development, inhibits tubule formation and bud growth in metanephroi. Inhibits WNT1/WNT4-mediated TCF-dependent transcription. Interacts with WNT4, WNT1, WNT2, WNT8, MYOC and FRZD6. Cell membrane or extracellular matrix-associated. Released by heparin-binding (By similarity). Differentially expressed in developing kidney. In 16 dpc embryos, highly expressed around the ureter and, also in all stromal elements, including the interstitial populations of the medulla and the outer layer of the cortex. In 19 dpc embryos, expression in the medulla is increased and is also found in the mesenchymal tissue surrounding the developing ureter. The FZ domain is involved in binding with Wnt ligands. Belongs to the secreted frizzled-related protein (sFRP) family.