title: The effects of 20-hydroxyecdysone on the metabolic labeling of membrane proteins in Drosophila imaginal discs.
abstract: 20-Hydroxyecdysone induces evagination of imaginal discs of Drosophila melanogaster cultured in vitro. The possible involvement of cell-surface proteins in this process has prompted us to study the synthesis of membrane proteins in imaginal discs. A procedure is reported for the isolation of membrane vesicle fractions from discs that are enriched for the plasma membrane enzyme, Na+/K+-ATPase, and that label with the surface-labeling reagent [125I]iodosulfanilic acid. 20-Hydroxyecdysone alters the pattern of [35S]methionine incorporation into polypeptides in these membrane vesicle fractions. Increased and decreased incorporation as well as changes in migration on two-dimensional gels of specific polypeptides are caused by the hormone. These changes parallel in time the onset and the continuation of evagination.
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D046508:Culture Techniques; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000254:growth & development*; D004441:Ecdysterone / Q000494:pharmacology*; D007814:Larva / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis*; D008715:Methionine / Q000378:metabolism; D008854:Microscopy, Electron; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D004441:Ecdysterone; D008715:Methionine; D000254:Sodium-Potassium-Exchanging ATPase