Molecular and Cellular Biochemistry

, 327:111

Regulation of the extracellular antioxidant selenoprotein plasma glutathione peroxidase (GPx-3) in mammalian cells

  • Filomena G. Ottaviano
  • Shiow-Shih Tang
  • Diane E. Handy
  • Joseph Loscalzo
Article

DOI: 10.1007/s11010-009-0049-x

Cite this article as:
Ottaviano, F.G., Tang, SS., Handy, D.E. et al. Mol Cell Biochem (2009) 327: 111. doi:10.1007/s11010-009-0049-x

Abstract

Plasma glutathione peroxidase (GPx-3) is a selenocysteine-containing extracellular antioxidant protein that catalyzes the reduction of hydrogen peroxide and lipid hydroperoxides. Selenoprotein expression involves the alternate recognition of a UGA codon as a selenocysteine codon and requires signals in the 3′-untranslated region (UTR), including a selenocysteine insertion sequence (SECIS), as well as specific translational cofactors. To ascertain regulatory determinants of GPx-3 expression and function, we generated recombinant GPx-3 (rGPX-3) constructs with various 3′-UTR, as well as a Sec73Cys mutant. In transfected Cos7 cells, the Sec73Cys mutant was expressed at higher levels than the wild type rGPx-3, although the wild type rGPx-3 had higher specific activity, similar to plasma purified GPx-3. A 3′-UTR with only the SECIS was insufficient for wild type rGPx-3 protein expression. Selenocompound supplementation and co-transfection with SECIS binding protein 2 increased wild type rGPx-3 expression. These results demonstrate the importance of translational mechanisms in GPx-3 expression.

Keywords

AntioxidantSelenocysteine3′-untranslated regionRegulation

Abbreviations

GPx-3

Plasma glutathione peroxidase

UTR

3′-Untranslated region

SECIS

Selenocysteine insertion sequence

rGPx-3

Recombinant GPx-3

GPx

Glutathione peroxidase

GSH

Glutathione

Sec

Selenocysteine

eEFSec

Sec-elongation factor

SBP2

SECIS binding protein 2

qRT-PCR

Qualitative real-time polymerase chain reaction

SelD

Human selenophosphate synthetase D

G3PDH

Glyceraldehyde-3-phosphate dehydrogenase

rLacZ

Recombinant Lac Z

TRx

Thioredoxin

Copyright information

© Springer Science+Business Media, LLC. 2009

Authors and Affiliations

  • Filomena G. Ottaviano
    • 1
    • 2
  • Shiow-Shih Tang
    • 2
  • Diane E. Handy
    • 2
  • Joseph Loscalzo
    • 2
  1. 1.Whitaker Cardiovascular Institute and Evans Department of MedicineBoston University School of MedicineBostonUSA
  2. 2.Department of MedicineBrigham and Women’s Hospital, Harvard Medical SchoolBostonUSA