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The ligand Jelly Belly (Jeb) activates the Drosophila Alk RTK to drive PC12 cell differentiation, but is unable to activate the Mouse ALK RTK
Author(s) -
Yang HaiLing,
Eriksson Therese,
Vernersson Emma,
Vigny Marc,
Hallberg Bengt,
Palmer Ruth H.
Publication year - 2007
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.21146
Subject(s) - biology , microbiology and biotechnology , receptor tyrosine kinase , ligand (biochemistry) , drosophila (subgenus) , drosophila melanogaster , mutant , receptor , signal transduction , genetics , gene
The Drosophila Alk receptor tyrosine kinase (RTK) drives founder cell specification in the developing visceral mesoderm and is crucial for the formation of the fly gut. Activation of Alk occurs in response to the secreted ligand Jelly Belly. No homologues of Jelly Belly are described in vertebrates, therefore we have approached the question of the evolutionary conservation of the Jeb–Alk interaction by asking whether vertebrate ALK is able to function in Drosophila . Here we show that the mouse ALK RTK is unable to rescue a Drosophila Alk mutant, indicating that mouse ALK is unable to recognise and respond to the Drosophila Jeb molecule. Furthermore, the overexpression of a dominant‐negative Drosophila Alk transgene is able to block the visceral muscle fusion event, which an identically designed dominant‐negative construct for the mouse ALK is not. Using PC12 cells as a model for neurite outgrowth, we show here for the first time that activation of dAlk by Jeb results in neurite extension. However, the mouse Alk receptor is unable to respond in any way to the Drosophila Jeb protein in the PC12 system. In conclusion, we find that the mammalian ALK receptor is unable to respond to the Jeb ligand in vivo or in vitro. These results suggest that either (i) mouse ALK and “mouse Jeb” have co‐evolved to the extent that mALK can no longer recognise the Drosophila Jeb ligand or (ii) that the mALK RTK has evolved such that it is no longer activated by a Jeb‐like molecule in vertebrates. J. Exp. Zool. (Mol. Dev. Evol.) 308B:269–282, 2007 . © 2007 Wiley‐Liss, Inc.