Characterization of selenoprotein P as a selenium supply protein.
Selenium (Se) is well known to be essential for cell culture when using a serum-free medium, but not when a medium containing serum is used. This finding suggests that serum contains some usable form of Se. To identify the Se-supplier, T-lymphoma (Jurkat) cells were cultured for 3 days in the presence of human serum immunodepleted of Se-containing serum protein, selenoprotein P or extracellular glutathione peroxidase. The Se-dependent enzyme activities (glutathione peroxidases and thioredoxin reductase) and Se content within the cells markedly decreased only when cultured with selenoprotein P-depleted serum. Compared with other Se-containing proteins, the addition of purified selenoprotein P to the selenoprotein P-depleted serum or a serum-free medium was the most effective for the recovery of cellular glutathione peroxidase activity (index of Se status). These results suggest that selenoprotein P functions as a Se-supply protein, delivering Se to the cells.
Saito
Yoshiro
Y
Department of Hygienic Chemistry, Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, Japan.
Takahashi
Kazuhiko
K
D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism*; D012643:Selenium / Q000737:chemistry* / Q000378:metabolism*; D051149:Selenoprotein P; D051140:Selenoproteins; D013880:Thioredoxin-Disulfide Reductase / Q000378:metabolism; D013997:Time Factors
D018076:DNA, Complementary; D011506:Proteins; D051149:Selenoprotein P; D051140:Selenoproteins; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D013880:Thioredoxin-Disulfide Reductase; D012643:Selenium