Connections Map OverviewDevelopmental Biology

Hedgehog Signaling Pathway in Drosophila

Science's STKE  09 Oct 2007:
Vol. 2007, Issue 407, pp. cm7
DOI: 10.1126/stke.4072007cm7


Studies in Drosophila have provided the framework for understanding human development and disease processes governed by the Hedgehog (Hh) family of secreted signaling molecules. The Drosophila proteins that participate in Hh-mediated signal transduction are highlighted in a Connections Map pathway.


This record contains information specific to the Hedgehog Signaling Pathway in Drosophila.

A role for the Hedgehog (Hh) signal transduction pathway in embryonic patterning is firmly established. The identification of Hh and most of the components in the pathway were initially described in Drosophila melanogaster (Fig. 1). Hh is produced as a precursor protein that is autocatalytically processed into a truncated protein containing an N-terminal signaling domain that is cholesterol-modified on the C terminus. Production and distribution of the secreted Hh protein require the action of Skinny hedgehog (Ski), which adds a palmitate moiety critical to Hh function on the N terminus of mature Hh, and Dispatched (Disp), a 12-transmembrane protein required for release of the dually lipidated Hh from the cell membrane.

Fig. 1.

Pathway image captured from the dynamic graphical display of the information in the Connections Maps available 14 September 2007. For a key to the colors and symbols and to access the underlying data, please visit the pathway (;CMP_20386).

Pathway response is activated upon binding of Hh to Patched (Ptc), which lifts the suppressive action of Ptc on the seven-transmembrane effector Smoothened (Smo). Activation of Smo entails accumulation of phosphorylated Smo and recruitment of a large cytoplasmic complex scaffolded by the kinesin-like molecule Costal-2 (Cos2) to the Smo cytoplasmic tail. Activation of the transcriptional effector Cubitus interruptus (Ci) entails inhibition of its proteolytic processing into a transcriptional repressor and nuclear accumulation of Ci in the nucleus. The kinase Fused (Fu), the protein Suppressor of fused [Su(fu)], and Cos2 all regulate subcellular distribution of Ci, whereas Fu and Cos2 are also necessary for Ci processing.

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Pathway Details

Scope: Specific

Organism: invertebrates: arthropods: insects: Drosophila


Canonical pathway: Hedgehog Signaling Pathway (;CMP_19889)

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