Frzb-1, an antagonist of Wnt-1 and Wnt-8, does not block signaling by Wnts -3A, -5A, or -11.

Frzb-1 is a secreted factor that was recently shown to inhibit signaling by Wnts 1 and 8. Frzb-1 contains an amino terminal domain that is homologous to the Drosophila polarity gene frizzled; several other secreted proteins that share this feature have now been identified. These findings raise the question of whether or not Frzb-1 is a general inhibitor of signaling by all Wnts. We show that signaling of Wnts -3A, 5A, and 11 is not blocked by Frzb-1, demonstrating that Frzb-1 can discriminate both between the principle functional Wnt classes that have been proposed and within them.