title: Endoplasmic reticulum stress induces the phosphorylation of small heat shock protein, Hsp27.
abstract: There are several reports describing participation of small heat shock proteins (sHsps) in cellular protein quality control. In this study, we estimated the endoplasmic reticulum (ER) stress-induced response of Hsp27 and alphaB-crystallin in mammalian cells. Treatment targeting the ER with tunicamycin or thapsigargin induced the phosphorylation of Hsp27 but not of alphaB-crystallin in U373 MG cells, increase being observed after 2-10 h and decline at 24 h. Similar phosphorylation of Hsp27 by ER stress was also observed with U251 MG and HeLa but not in COS cells and could be blocked using SB203580, an inhibitor of p38 MAP kinase. Other protein kinase inhibitors, like Gö6983, PD98059, and SP600125, inhibitors of protein kinase C (PKC), p44/42 MAP kinase, and JNK, respectively, were without major influence. Prolonged treatment with tunicamycin but not thapsigargin for 48 h caused the second induction of the phosphorylation of Hsp27 in U251 MG cells. Under these conditions, the intense perinuclear staining of Hsp27, with some features of aggresomes, was observed in 10%-20% of the cells.
authors.affiliation: Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi 480-0392, Japan. itohide@inst-hsc.jp
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ito
authors.forename: Ikuko
authors.initials: I
authors.lastname: Iwamoto
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Inaguma
authors.forename: Takenori
authors.initials: T
authors.lastname: Takizawa
authors.forename: Koh-ichi
authors.initials: K
authors.lastname: Nagata
authors.forename: Tomiko
authors.initials: T
authors.lastname: Asano
authors.forename: Kanefusa
authors.initials: K
authors.lastname: Kato
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology; D015153:Blotting, Western; D019556:COS Cells; D002467:Cell Nucleus / Q000378:metabolism; D002522:Chlorocebus aethiops; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005910:Glioma / Q000378:metabolism / Q000473:pathology; D055551:HSP27 Heat-Shock Proteins; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism; D018832:Molecular Chaperones; D009363:Neoplasm Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D013312:Stress, Physiological; D019284:Thapsigargin / Q000494:pharmacology; D014415:Tunicamycin / Q000494:pharmacology; D038203:alpha-Crystallin B Chain / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D055551:HSP27 Heat-Shock Proteins; C057725:HSPB1 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D038203:alpha-Crystallin B Chain; D014415:Tunicamycin; D019284:Thapsigargin; D011493:Protein Kinase C; D048031:JNK Mitogen-Activated Protein Kinases; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases