title: Imaging sites of receptor dephosphorylation by PTP1B on the surface of the endoplasmic reticulum.
abstract: When bound by extracellular ligands, receptor tyrosine kinases (RTKs) on the cell surface transmit critical signals to the cell interior. Although signal termination is less well understood, protein tyrosine phosphatase-1B (PTP1B) is implicated in the dephosphorylation and inactivation of several RTKs. However, PTP1B resides on the cytoplasmic surface of the endoplasmic reticulum (ER), so how and when it accesses RTKs has been unclear. Using fluorescence resonance energy transfer (FRET) methods, we monitored interactions between the epidermal- and platelet-derived growth factor receptors and PTP1B. PTP1B-catalyzed dephosphorylation required endocytosis of the receptors and occurred at specific sites on the surface of the ER. Most of the RTKs activated at the cell surface showed interaction with PTP1B after internalization, establishing that RTK activation and inactivation are spatially and temporally partitioned within cells.
authors.affiliation: Cancer Biology Program, Division of Hematology-Oncology, Department of Medicine, Beth Israel-Deaconess Medical Center, Boston, MA 02115, USA.
authors.forename: Fawaz G
authors.initials: FG
authors.lastname: Haj
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Verveer
authors.forename: Anthony
authors.initials: A
authors.lastname: Squire
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Neel
authors.forename: Philippe I H
authors.initials: PI
authors.lastname: Bastiaens
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D020134:Catalytic Domain; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000201:enzymology*; D004735:Energy Transfer; D004815:Epidermal Growth Factor / Q000378:metabolism / Q000494:pharmacology; D066246:ErbB Receptors / Q000378:metabolism*; D005453:Fluorescence; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology; D021381:Protein Transport; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D010982:Platelet-Derived Growth Factor; D011993:Recombinant Fusion Proteins; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D017479:Receptors, Platelet-Derived Growth Factor; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D017027:Protein Tyrosine Phosphatases; C516609:Ptpn1 protein, mouse