Two integral membrane proteins, Patched and Smoothened, were for a long time thought to comprise a preformed receptor complex for secreted Hedgehog signalling proteins. Recent analyses of the subcellular distribution of these proteins argue strongly against this simple model.

In Drosophila, patched encodes a negative regulator of Hedgehog signaling. Biochemical experiments have demonstrated that vertebrate patched homologues might function as a Sonic hedgehog (Shh) receptor. In mice, two patched homologues, Ptch and Ptch2, have been identified. Sequence comparison have suggested that they might possess distinct properties in Shh signaling. In the developing tooth, h...

Hedgehog signaling, mediated through its Patched-Smoothened receptor complex, is essential for pattern formation in animal development. Activating mutations within Smoothened have been associated with basal cell carcinoma, suggesting that smoothened is a protooncogene. Thus, regulation of Smoothened levels might be critical for normal development. We show that Smoothened protein levels in Droso...

The membrane protein, Patched, plays a critical role in patterning embryonic and imaginal tissues in Drosophila. patched constitutively inactivates the transcription of target genes such as wingless, decapentaplegic, and patched itself. The secreted protein, Hedgehog, induces transcription of target genes by opposing the Patched signaling pathway. Using the Gal4 UAS system we have overexpressed...

H edgehog protein and its receptor are made for each other, but even this perfect couple needs a little help to get together. Li et al. (1) reveal that a proteoglycan plays cupid for the molecules and sparks signal transduction through the Hedgehog pathway, a mechanism exploited by a type of childhood cancer. During development, Hedgehog proteins are sculptors, helping to mold the embryo’s limb...