Hyperthermic stress-induced increase in the expression of glutamate-cysteine ligase and glutathione levels in the symbiotic sea anemone Aiptasia pallida

Comp Biochem Physiol B Biochem Mol Biol. 2008 Sep;151(1):133-8. doi: 10.1016/j.cbpb.2008.06.007. Epub 2008 Jun 17.

Abstract

Hyperthermic stress is known to trigger the loss of unicellular algae from a number of symbiotic cnidarians, a phenomenon commonly referred to as bleaching. Oxidative and nitrosative stress have been suggested to play a major role during the process of bleaching, however the underlying molecular mechanisms are still poorly understood. In animals, the intracellular tripeptide glutathione (GSH) is involved in antioxidant defense, redox homeostasis and intracellular redox signaling. Therefore, we tested the hypothesis that hyperthermal stress-induced bleaching in Aiptasia pallida, a model for symbiotic cnidarians, results in increased levels of GSH synthesis. We report the cDNA sequence and functional analysis of the catalytic subunit of glutamate-cysteine ligase (GCLC), which catalyzes the rate-limiting step in GSH biosynthesis. In a time-series experiment, both GCLC gene expression and total GSH levels increased 4- and 1.5-fold, respectively, in response to hyperthermal stress. These results suggest that hyperthermal stress triggers adaptive increases in intracellular GSH biosynthesis in cnidarians as a protective response to oxidative/nitrosative stress. Our results show the conserved function of GCLC and GSH across animals while placing a new perspective on the role of GSH in redox signaling during cnidarian bleaching.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Catalytic Domain / genetics
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • Fever / enzymology
  • Fever / genetics*
  • Fever / metabolism
  • Glutamate-Cysteine Ligase / chemistry
  • Glutamate-Cysteine Ligase / genetics*
  • Glutamate-Cysteine Ligase / metabolism*
  • Glutathione / metabolism*
  • Molecular Sequence Data
  • Oxidative Stress / genetics
  • Sea Anemones / metabolism*
  • Sequence Analysis, DNA
  • Symbiosis*
  • Up-Regulation*

Substances

  • DNA, Complementary
  • Glutamate-Cysteine Ligase
  • Glutathione