TY - JOUR

T1 - Differential role for ERK2 in anoxia-induced activation of transcription and translation of Hsp70 in NIH 3T3 cells

AU - Ossum, Carlo

AU - Lauritsen, Anders N.

AU - Karottki, Dorina Gabriela

AU - Hoffmann, Else Kay

N1 - Copyright © 2011 S. Karger AG, Basel.

PY - 2011

Y1 - 2011

N2 - Hsp70 has the ability to enhance the recovery of stressed cells by its ability to catalyze the reassembly of damaged proteins. Such a chaperoning function is essential for the Hsp70-mediated protection against anoxic stress that causes protein denaturation. We have studied induction of both transcription and translation of Hsp70 during recovery from chemical anoxia and the role of the extracellular signal regulated kinase ERK2 in this induction of Hsp70. 10 mM azide for 30 minutes (chemical anoxia) significantly inhibited the activity of ERK2 (measured as phospho-ERK) but the ERK-2 activity is rapidly increased in a MEK-independen manner, when azide is washed out of the cells. Chemical anoxia and overnight recovery induced Hsp70 expression (analyzed by Western blotting) and this was inhibited by actinomycin D as well as by cycloheximide showing that induction of both translation and transcription was involved. Inhibition of the MAP kinase p38, which was transiently activated during chemical anoxia, had no effect on the increase in Hsp70 expression whereas an inhibitor of reactive oxygen species and inhibition of the phosphatase PP1 and PP2a inhibited the increase in Hsp70 expression. Inhibition of ERK2 by the MEK inhibitor PD98059 resulted in strong inhibition of Hsp70 protein expression and simultaneous stimulation of hsp70 transcription.

AB - Hsp70 has the ability to enhance the recovery of stressed cells by its ability to catalyze the reassembly of damaged proteins. Such a chaperoning function is essential for the Hsp70-mediated protection against anoxic stress that causes protein denaturation. We have studied induction of both transcription and translation of Hsp70 during recovery from chemical anoxia and the role of the extracellular signal regulated kinase ERK2 in this induction of Hsp70. 10 mM azide for 30 minutes (chemical anoxia) significantly inhibited the activity of ERK2 (measured as phospho-ERK) but the ERK-2 activity is rapidly increased in a MEK-independen manner, when azide is washed out of the cells. Chemical anoxia and overnight recovery induced Hsp70 expression (analyzed by Western blotting) and this was inhibited by actinomycin D as well as by cycloheximide showing that induction of both translation and transcription was involved. Inhibition of the MAP kinase p38, which was transiently activated during chemical anoxia, had no effect on the increase in Hsp70 expression whereas an inhibitor of reactive oxygen species and inhibition of the phosphatase PP1 and PP2a inhibited the increase in Hsp70 expression. Inhibition of ERK2 by the MEK inhibitor PD98059 resulted in strong inhibition of Hsp70 protein expression and simultaneous stimulation of hsp70 transcription.

KW - Animals

KW - Cell Hypoxia

KW - Cycloheximide

KW - Dactinomycin

KW - Flavonoids

KW - HSP70 Heat-Shock Proteins

KW - Mice

KW - Mitogen-Activated Protein Kinase 1

KW - NIH 3T3 Cells

KW - Protein Biosynthesis

KW - Protein Phosphatase 1

KW - Protein Phosphatase 2

KW - Protein Synthesis Inhibitors

KW - Reactive Oxygen Species

KW - Sodium Azide

KW - Transcriptional Activation

KW - p38 Mitogen-Activated Protein Kinases

U2 - 10.1159/000325213

DO - 10.1159/000325213

M3 - Journal article

C2 - 21325828

VL - 27

SP - 109

EP - 120

JO - Cellular Physiology and Biochemistry

JF - Cellular Physiology and Biochemistry

SN - 1015-8987

IS - 2

ER -