Cmn to Send Hh

Science's STKE  08 Jan 2002:
Vol. 2002, Issue 114, pp. tw14
DOI: 10.1126/stke.2002.114.tw14

Hedgehog (Hh) proteins are secreted factors that regulate tissue patterning during vertebrate and invertebrate development. For example, Hh controls the growth and pattering of the anterior and posterior of the Drosophila wing. All but one of the components of the Hh signaling pathway that have been identified thus far involve regulating the transduction of the signal in Hh-receiving cells. Amanai and Jiang have used a tissue-specific mosaic genetic screen in Drosophila to identify central missing (Cmn) as an important regulator of Hh signaling in Hh-releasing cells. Cmn loss-of-function mutants bear eye and wing developmental defects similar to those exhibited in flies with mutated Dispatched, a membrane protein that controls the release of mature, cleaved, and cholesterol-modified Hh from secreting cells. Cmn appears not to regulate Hh expression but rather trafficking of Hh to the surface of secreting cells. Overexpression of cleaved and cholesterol-modified Hh could not rescue the Cmn mutant phenotype, indicating that Cmn regulation of Hh action does not involve those aspects of the Hh maturation process. Cmn encodes a membrane-bound acyltransferase, and the authors suggest that it may regulate Hh palmitoylation. Cmn is similar to another acyltransferase called Porcupine, which is required for the secretion of another developmentally important signaling molecule, Wingless.

K. Amanai, J. Jiang, Distinct roles of Central missing and Dispatched in sending the Hedgehog signal. Development 128, 5119-5127 (2001). [Online Journal]