title: Egfr signaling regulates ommatidial rotation and cell motility in the Drosophila eye via MAPK/Pnt signaling and the Ras effector Canoe/AF6.
abstract: Epidermal Growth Factor-receptor (Egfr) signaling is evolutionarily conserved and controls a variety of different cellular processes. In Drosophila these include proliferation, patterning, cell-fate determination, migration and survival. Here we provide evidence for a new role of Egfr signaling in controlling ommatidial rotation during planar cell polarity (PCP) establishment in the Drosophila eye. Although the signaling pathways involved in PCP establishment and photoreceptor cell-type specification are beginning to be unraveled, very little is known about the associated 90 degrees rotation process. One of the few rotation-specific mutations known is roulette (rlt) in which ommatidia rotate to a random degree, often more than 90 degrees. Here we show that rlt is a rotation-specific allele of the inhibitory Egfr ligand Argos and that modulation of Egfr activity shows defects in ommatidial rotation. Our data indicate that, beside the Raf/MAPK cascade, the Ras effector Canoe/AF6 acts downstream of Egfr/Ras and provides a link from Egfr to cytoskeletal elements in this developmentally regulated cell motility process. We provide further evidence for an involvement of cadherins and non-muscle myosin II as downstream components controlling rotation. In particular, the involvement of the cadherin Flamingo, a PCP gene, downstream of Egfr signaling provides the first link between PCP establishment and the Egfr pathway.
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D005123:Eye / Q000196:embryology*; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D016547:Kinesins / Q000378:metabolism; D008024:Ligands; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology; D009218:Myosins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000502:physiology; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors; D018631:ras Proteins / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D005136:Eye Proteins; D008024:Ligands; D009419:Nerve Tissue Proteins; D011518:Proto-Oncogene Proteins; D014157:Transcription Factors; C092747:cno protein, Drosophila; C083884:pnt protein, Drosophila; C075638:aos protein, Drosophila; D066246:ErbB Receptors; D020928:Mitogen-Activated Protein Kinases; D009218:Myosins; D016547:Kinesins; D018631:ras Proteins