Background：

Receptor for Wnt proteins. 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. A second signaling pathway involving PKC and calcium fluxes has been seen for some family members， but it is not yet clear if it represents a distinct pathway or if it can be integrated in the canonical pathway， as PKC seems to be required for Wnt-mediated inactivation of GSK-3 kinase. Both pathways seem to involve interactions with G-proteins. May be involved in transduction and intercellular transmission of polarity information during tissue morphogenesis and/or in differentiated tissues. Together with FZD3， is involved in the neural tube closure and plays a role in the regulation of the establishment of planar cell polarity (PCP)， particularly in the orientation of asymmetric bundles of stereocilia on the apical faces of a subs