title: Sch proteins are localized on endoplasmic reticulum membranes and are redistributed after tyrosine kinase receptor activation.
abstract: The intracellular localization of Shc proteins was analyzed by immunofluorescence and immunoelectron microscopy in normal cells and cells expressing the epidermal growth factor receptor or the EGFR/erbB2 chimera. In unstimulated cells, the immunolabeling was localized in the central perinuclear area of the cell and mostly associated with the cytosolic side of rough endoplasmic reticulum membranes. Upon epidermal growth factor treatment and receptor tyrosine kinase activation, the immunolabeling became peripheral and was found to be associated with the cytosolic surface of the plasma membrane and endocytic structures, such as coated pits and endosomes, and with the peripheral cytosol. Receptor activation in cells expressing phosphorylation-defective mutants of Shc and erbB-2 kinase showed that receptor autophosphorylation, but not Shc phosphorylation, is required for redistribution of Shc proteins. The rough endoplasmic reticulum localization of Shc proteins in unstimulated cells and their massive recruitment to the plasma membrane, endocytic structures, and peripheral cytosol following receptor tyrosine kinase activation could account for multiple putative functions of the adaptor protein.
authors.affiliation: Dipartimento di Medicina Sperimentale e Patologia, Universit¿a di Roma "La Sapienza", Italy.
authors.forename: L V
authors.initials: LV
authors.lastname: Lotti
authors.forename: L
authors.initials: L
authors.lastname: Lanfrancone
authors.forename: E
authors.initials: E
authors.lastname: Migliaccio
authors.forename: C
authors.initials: C
authors.lastname: Zompetta
authors.forename: G
authors.initials: G
authors.lastname: Pelicci
authors.forename: A E
authors.initials: AE
authors.lastname: Salcini
authors.forename: B
authors.initials: B
authors.lastname: Falini
authors.forename: P G
authors.initials: PG
authors.lastname: Pelicci
authors.forename: M R
authors.initials: MR
authors.lastname: Torrisi
mesh_terms: D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D004789:Enzyme Activation; D004815:Epidermal Growth Factor / Q000494:pharmacology; D066246:ErbB Receptors / Q000096:biosynthesis* / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D051379:Mice; D016253:Microscopy, Immunoelectron; D010766:Phosphorylation; D014176:Protein Biosynthesis; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D011994:Recombinant Proteins / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D013347:Subcellular Fractions / Q000378:metabolism / Q000648:ultrastructure; D014162:Transfection
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D011506:Proteins; D020794:Receptor Protein-Tyrosine Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; C528034:Shc1 protein, mouse