title: Echinoid is essential for regulation of Egfr signaling and R8 formation during Drosophila eye development.
abstract: Precisely regulated Egfr activity is essential for normal development and cell differentiation. We demonstrate that the transmembrane protein Echinoid is required to downregulate Egfr activity in the developing Drosophila eye, ensuring a normal array of R8 photoreceptor neurons. Echinoid is an L1-type transmembrane molecule that is expressed in all cells of the eye imaginal discs and, unlike many other Egfr inhibitors, does not appear to be regulated transcriptionally. Echinoid co-precipitates with Egfr from cultured cells and eye imaginal discs, and Egfr activity promotes tyrosine phosphorylation of Echinoid. These observations suggest that Echinoid inhibits Egfr through direct interactions.
authors.affiliation: Department of Molecular Biology and Pharmacology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8103, St Louis, MO 63110, USA.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Spencer
authors.forename: Ross L
authors.initials: RL
authors.lastname: Cagan
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000378:metabolism; D015536:Down-Regulation; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000254:growth & development*; D004789:Enzyme Activation; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D009024:Morphogenesis; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D010766:Phosphorylation; D017956:Photoreceptor Cells, Invertebrate / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D015815:Cell Adhesion Molecules; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D066246:ErbB Receptors; D048049:Extracellular Signal-Regulated MAP Kinases; D005136:Eye Proteins; D009419:Nerve Tissue Proteins; D012097:Repressor Proteins; C422623:ED protein, Drosophila; C082142:ato protein, Drosophila; C075638:aos protein, Drosophila; C086795:rl protein, Drosophila