Frizzled homolog 1 (FZD1), also known as Frizzled-1, a member of the G-protein-coupled receptor superfamily, mediates Wnt signaling by serving as a co-receptor with LRP-5 for Wnt ligands. The FZD1 protein contains a signal peptide, a cysteine-rich domain in the N-terminal extracellular region, 7 transmembrane domains, and a C-terminal PDZ domain-binding motif.

Frizzled-1, also known as FZD1, belongs to theG-protein coupled receptor Fz/Smo family. FZD1 contains a signal peptide, a cysteine-rich domain in the N-terminal extracellular region, 7 transmembrane domains, and a C-terminal PDZ domain-binding motif. FZD1 is expressed in adult heart, placenta, lung, kidney, pancreas, prostate, and ovary and in fetal lung and kidney. Frizzled is a family of G protein-coupled receptor proteins that serve as receptors in the Wnt signaling pathway and other signaling pathways. When activated, Frizzled leads to activation of Dishevelled in the cytosol. Frizzled proteins and the genes encoding them have been identified in an array of animals, from sponges to humans. Frizzled proteins play key roles in governing cell polarity, embryonic development, formation of neural synapses, cell proliferation, and many other processes in developing and adult organisms. Most of frizzled receptors are coupled to the beta-catenin canonical signaling pathway, which leads to the activation of disheveled proteins, inhibition of GSK-3 kinase, nuclear accumulation of beta-catenin and activation of Wnt target genes.

Familial exudative vitreoretinopathy (FEVR) is a hereditary blinding disorder that features defects in retinal vascular development. Mutations in FZD4 are known to cause autosomal dominant exudative vitreoretinopathy (EVR1). The mutations in FZD4 are associated with the phenotypes of retinal folds or ectopic macula in FEVR. Frizzled 4 Protein, Human, Recombinant (His) is expressed in HEK293 mammalian cells with His tag. The predicted molecular weight is 17.7 kDa and the accession number is Q9ULV1.

Familial exudative vitreoretinopathy (FEVR) is a hereditary blinding disorder that features defects in retinal vascular development. Mutations in FZD4 are known to cause autosomal dominant exudative vitreoretinopathy (EVR1). The mutations in FZD4 are associated with the phenotypes of retinal folds or ectopic macula in FEVR. Frizzled 4 Protein, Human, Recombinant (hFc) is expressed in HEK293 mammalian cells with hFc tag. The predicted molecular weight is 43.3 kDa and the accession number is Q9ULV1.

Secreted frizzled-related protein 1, also known as sFRP1, is a 35 kDa prototypical member of the SFRP family. SFRP family consists of five secreted glycoproteins in humans acting as extracellular signaling ligands. Each is approximately 3 amino acids in length and contains a cysteine-rich domain (CRD) that shares 3-5% sequence homology with the CRD of Frizzled (Fz) receptors, a putative signal sequence, and a conserved hydrophilic carboxy-terminal domain. SFRPs act as soluble modulators of Wnt signaling, counteracting Wnt-induced effects at high concentrations and promoting them at lower concentrations. SFRPs are able to bind Wnt proteins and Fz receptors in the extracellular compartment. The interaction between SFRPs and Wnt proteins prevents the latter from binding the Fz receptors. The Wnt pathway plays a key role in embryonic development, cell differentiation and cell proliferation. The deregulation of this critical developmental pathway occurs in several human tumor entities. Mouse sFRP1 is highly expressed in kidney and embryonic heart, as well as in the eye, where it is principally localized to the ciliary body and the lens epithelium.