Leading Wnt down a PCP path: Cthrc1 acts as a coreceptor in the Wnt-PCP pathway

Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders, NIH, Bethesda, MD 20892, USA.
Developmental Cell (Impact Factor: 9.71). 08/2008; 15(1):7-8. DOI: 10.1016/j.devcel.2008.06.008
Source: PubMed


The Wnt signaling pathway controls myriad developmental events including cell proliferation, migration, patterning, fate, and differentiation. Many Wnt-mediated events are regulated through a canonical pathway in which binding of a Wnt to a Frizzled (Fzd) receptor leads to stabilization of β-catenin. However, in other contexts, Wnt-Fz binding leads to activation of an alternate pathway that acts through a different set of signaling molecules to regulate planar cell polarity (PCP) and related developmental events. PCP refers to the uniform orientation of a particular aspect of a group of cells, usually within an epithelial plane. The most obvious examples of PCP are the orientation of actin-based hairs along the wing and body of Drosophila, the orientation of hair follicles on the vertebrate body and the orientation of mechanosensory hair cells in the mammalian auditory sensory epithelium, the organ of Corti. While a role for wg, the Drosophila homolog of Wnt, in PCP has not been demonstrated, loss of Wnt function clearly disrupts PCP in vertebrates (reviewed in Karner et al., 2006). Results from genetic deletion studies in mice have indicated that specific Wnt and Fzd genes mediate PCP signaling (Wang et al., 2006). However, biochemical studies suggest that Wnt-Fzd interactions may be fairly promiscuous with limited evidence for formation of specific ligand-receptor pairs (reviewed in Kikuchi et al., 2007).

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