title: Distinct roles for two receptor tyrosine kinases in epithelial branching morphogenesis in Drosophila.
abstract: Branching morphogenesis is a widespread mechanism used to increase the surface area of epithelial organs. Many signaling systems steer development of branched organs, but it is still unclear which cellular processes are regulated by the different pathways. We have used the development of the air sacs of the dorsal thorax of Drosophila to study cellular events and their regulation via cell-cell signaling. We find that two receptor tyrosine kinases play important but distinct roles in air sac outgrowth. Fgf signaling directs cell migration at the tip of the structure, while Egf signaling is instrumental for cell division and cell survival in the growing epithelial structure. Interestingly, we find that Fgf signaling requires Ras, the Mapk pathway, and Pointed to direct migration, suggesting that both cytoskeletal and nuclear events are downstream of receptor activation. Ras and the Mapk pathway are also needed for Egf-regulated cell division/survival, but Pointed is dispensable.
authors.affiliation: Department of Biology, Biozentrum der Universität Basel, Klingelbergstrasse 70, CH-4056 Basel, Switzerland.
authors.forename: Clemens
authors.initials: C
authors.lastname: Cabernard
authors.forename: Markus
authors.initials: M
authors.lastname: Affolter
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002455:Cell Division; D002465:Cell Movement; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival; D003599:Cytoskeleton / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D019076:Transgenes / Q000502:physiology; D018631:ras Proteins / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D017468:Receptors, Fibroblast Growth Factor; D014157:Transcription Factors; C083884:pnt protein, Drosophila; D005346:Fibroblast Growth Factors; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins