FIGURE 1.

The cSP peptide is homologous to the conserved extracellular CRD of human Frizzled receptors. A, sequence alignments of cSP with members of the human Fz family. Identical residues are shown in red and highly conservative replacements are in blue. B, ribbon representation of the structure of the extracellular domain of Fz5. The amino acid sequence homologous to the cSP peptide is highlighted in red and orange. Residues involved in Wnt binding (5) are shown in yellow and orange. The figure was generated using RasMol and the atomic coordinates for Fz5 (Protein Data Bank accession code 1IJY; Ref. 5). C, wells in a 96-well plate were coated with either 1 μg of Aβ40 or 1 μg of BSA, blocked with 1% BSA, and incubated with 500 ng of Fz5CRD or Fz4CRD. After washing, binding was evaluated with anti-Fz4 or anti-Fz5 antibody. The plot shows results from densitometric quantification of the binding data using National Institutes of Health Image J software. Each bar represents the average of two independent experiments performed in triplicate. The blot illustrates one of the experiments performed.