SFRP1 Active Protein

This gene encodes a member of the SFRP family that contains a cysteine-rich domain homologous to the putative Wnt-binding site of Frizzled proteins. Members of this family act as soluble modulators of Wnt signaling; epigenetic silencing of SFRP genes leads to deregulated activation of the Wnt-pathway which is associated with cancer. This gene may also be involved in determining the polarity of photoreceptor cells in the retina. [provided by RefSeq, Sep 2009]

SFRP1: 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. 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 WNT1, WNT2 and FRZD6. Interacts with WNT4 and WNT8. Down-regulated in colorectal and breast tumors. Up- regulated in uterine leiomyomas under high estrogenic conditions. Expression, in leiomyomal cells, also increased both under hypoxic and serum deprivation conditions. Widely expressed. Absent from lung, liver and peripheral blood leukocytes. Highest levels in heart and fetal kidney. Also expressed in testis, ovary, fetal brain and lung, leiomyomal cells, myometrial cells and vascular smooth muscle cells. Expressed in foreskin fibroblasts and in keratinocytes. Belongs to the secreted frizzled-related protein (sFRP) family.

Protein type: Secreted; Secreted, signal peptide

Chromosomal Location of Human Ortholog: 8p11.21

Cellular Component: extracellular matrix; proteinaceous extracellular matrix; extracellular space; cell surface; plasma membrane; extracellular region; integral to membrane; intracellular; cytosol

Molecular Function: G-protein coupled receptor activity; heparin binding; identical protein binding; Wnt-protein binding; Wnt receptor activity; protein binding; frizzled binding; cysteine-type endopeptidase activity; drug binding

Biological Process: negative regulation of osteoclast differentiation; negative regulation of Wnt receptor signaling pathway; somatic stem cell maintenance; positive regulation of apoptosis; positive regulation of transcription, DNA-dependent; dorsal/ventral axis specification; Wnt receptor signaling pathway through beta-catenin; proteolysis; response to organic cyclic substance; negative regulation of BMP signaling pathway; negative regulation of insulin secretion; negative regulation of cell proliferation; positive regulation of focal adhesion formation; ureteric bud development; positive regulation of cell proliferation; positive regulation of stress fiber formation; negative regulation of ossification; positive regulation of smoothened signaling pathway; negative regulation of osteoblast differentiation; positive regulation of cell-matrix adhesion; negative regulation of cell migration; positive regulation of Wnt receptor signaling pathway; female gonad development; negative regulation of epithelial cell proliferation; response to drug; negative regulation of B cell differentiation; negative regulation of peptidyl-tyrosine phosphorylation; negative regulation of JNK activity; menstrual cycle phase; male gonad development; digestive tract morphogenesis; cellular response to starvation; regulation of angiogenesis; positive regulation of cell growth; osteoblast differentiation; negative regulation of fibroblast proliferation; negative regulation of bone remodeling; neural tube closure; positive regulation of fat cell differentiation; hemopoietic progenitor cell differentiation; negative regulation of osteoblast proliferation; neural crest cell fate commitment; negative regulation of cell growth; negative regulation of transcription, DNA-dependent; positive regulation of epithelial cell proliferation; negative regulation of apoptosis