Kinase activity, heat shock protein 27 phosphorylation, and lung epithelial cell glutathione

Robert M. Jackson, Rolando Garcia-Rojas

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The 27-kDa heat shock protein (Hps27) is phosphorylated in a way that appears to regulate antioxidant defenses by mitogen-activated protein kinase (MAPK)-activated protein kinase 2 (MK2), a component of the p38MAPK pathway. To investigate the role of Hsp27 in cellular resistance to oxidant stress, lung cells (A549) were incubated with MAPK inhibitors to investigate the pathway's role in antioxidant defense. Cells were harvested for measurement of reduced gluthathione and glutathione disulfide (GSH and GSSH); or, exposed to 2,3-dimethoxy-1,4-napthoquinone (DMNQ). Inhibition of MAPK with SB203580 decreased total cellular glutathione (mean ± SE): Vehicle, 150 ± 20 μM; SB203580, 57 ± 10* (*P <.01). Inhibition of MAPK tripled [GSSG]/[GSH]: Vehicle, 0.29 ± 0.09; SB203580, 1.06 ± 0.43* (*P >.05; n = 6 per group). Hsp27 protein content did not change significantly after MAPK inhibition: Vehicle 2.20 ± 0.24 ng/mg protein; SB203580, 2.03 ± 0.34 (P >.05). Transfection of epithelial cells with wild-type (pcDNA-HA-Hsp27) or phosphomimic (pcDNA-HA-Hsp27-S3D) vector increased Hsp27 protein, which significantly protected cells from oxidant stress. Inhibition of the MAPK system, including p38MAPK, results in cellular oxidant stress. Hsp27, which is phosphorylated by MK2 in the MAPK pathway, protects epithelial cells from oxidant stress.

Original languageEnglish (US)
Pages (from-to)245-262
Number of pages18
JournalExperimental Lung Research
Volume34
Issue number5
DOIs
StatePublished - Jun 1 2008

Keywords

  • Glutathione
  • Heat shock protein
  • Hypoxia
  • Kinases
  • Reactive oxygen species

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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