Post-translational processing of selenoprotein P: implications of glycosylation for its utilisation by target cells
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Holger Steinbrenner
Abstract
Selenoprotein P (SeP) is a highly glycosylated plasma protein containing up to 10 selenocysteine residues. It is secreted by hepatocytes and also by the human hepatoma cell line HepG2. Pharmacological inhibitors interfering with N-glycosylation, intracellular trafficking and calcium homeostasis were applied to examine post-translational processing and secretion of SeP by HepG2 cells. In parallel, the prototypic secretory glycoprotein α1-antitrypsin was used as technical control. Secretion of SeP was stimulated by increasing the extracellular calcium concentration and by inhibiting the release of sequestered calcium through dantrolene or U-73122. In contrast, brefeldin A and thapsigargin suppressed SeP secretion. Tunicamycin and monensin induced the synthesis of truncated non-glycosylated and partially glycosylated forms of SeP, which were secreted in spite of their impaired glycosylation. Both non-glycosylated and partially glycosylated SeP is utilised as selenium donor by target cells: impaired glycosylation affected neither the ability of SeP to induce the synthesis of the selenoenzyme cytosolic glutathione peroxidase nor its capacity to protect endothelial cells from oxidative stress.
©2007 by Walter de Gruyter Berlin New York
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Articles in the same Issue
- Selenoproteins – biochemistry and clinical relevance
- Selenium in mammalian spermiogenesis
- Selenium in chemistry and biochemistry in comparison to sulfur
- Molecular biology of glutathione peroxidase 4: from genomic structure to developmental expression and neural function
- Physiological role of phospholipid hydroperoxide glutathione peroxidase in mammals
- Activation of the glutathione peroxidase 2 (GPx2) promoter by β-catenin
- Effect of age on sexually dimorphic selenoprotein expression in mice
- Post-translational processing of selenoprotein P: implications of glycosylation for its utilisation by target cells
- Selenoproteins of the thyroid gland: expression, localization and possible function of glutathione peroxidase 3
- Towards understanding selenocysteine incorporation into bacterial proteins
- Glutathione- and thioredoxin-related enzymes are modulated by sulfur-containing chemopreventive agents
- B- and T-cell-specific inactivation of thioredoxin reductase 2 does not impair lymphocyte development and maintenance
- Effect of selenium on thioredoxin reductase activity in Txnrd1 or Txnrd2 hemizygous mice
- Influence of pH and flanking serine on the redox potential of S-S and S-Se bridges of Cys-Cys and Cys-Sec peptides
- An essential role for Pin1 in Xenopus laevis embryonic development revealed by specific inhibitors
- Glucocorticoid receptor-mediated expression of kallikrein 10 in human breast cancer cell lines
