How TGF-β-type ligands achieve signaling specificity during development is only partially understood. Here, we show that Dawdle, one of four Activin-type ligands in Drosophila, preferentially signals through Baboc, one of three isoforms of the Activin Type-I receptor that are expressed during development. In cell culture, Dawdle signaling is active in the presence of the Type-II receptor Punt but not Wit, demonstrating that the Type-II receptor also contributes to the specificity of the signaling complex. During development, different larval tissues express unique combinations of these receptors, and ectopic expression of Baboc in a tissue where it is not normally expressed at high levels can make that tissue sensitive to Dawdle signaling. These results reveal a mechanism by which distinct cell types can discriminate between different Activin-type signals during development as a result of differential expression of Type-I receptor isoforms.
|Original language||English (US)|
|Number of pages||8|
|Journal||Mechanisms of Development|
|State||Published - Dec 2009|
Bibliographical noteFunding Information:
We thank members of the O’Connor lab for helpful discussions and A. Peterson for both technical support and comments on the manuscript. P.A.J. was funded, in part, by NIH predoctoral training grant T32 HD007430-11A1. T.L. and X.Z. were funded by NIH grant NS42049 to T.L. M.B.O. is an Investigator with the Howard Hughes Medical Institute.