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Science Forum Index » Life Extension Forum » Selenium and MsrB
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| Tim |
 Posted: Mon Jan 12, 2004 2:06 pm |
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Proc Natl Acad Sci U S A. 2003 Jun 24;100(13):7486-90. Epub 2003 Jun
05. Related Articles, Links
Selenium-deficient diet enhances protein oxidation and affects
methionine sulfoxide reductase (MsrB) protein level in certain mouse
tissues.
Moskovitz J, Stadtman ER.
Laboratory of Biochemistry, National Heart, Lung, and Blood Institute,
National Institutes of Health, Bethesda, MD 20892, USA.
moskovij@nhlbi.nih.gov
Mammals contain two methionine sulfoxide (MetO) reductases, MsrA and
MsrB, that catalyze the thioredoxin-dependent reduction of the S-MetO
and R-MetO derivatives, respectively, to methionine. The major
mammalian MsrB is a selenoprotein (except in the heart). Here, we show
that there is a loss of MsrB activity in the MsrA-/- mouse that
correlates with parallel losses in the levels of MsrB mRNA and MsrB
protein, suggesting that MsrA might have a role in MsrB transcription.
Moreover, mice that were grown on a selenium-deficient (SD) diet
showed a substantial decrease in the levels of MsrB-catalytic
activity, MsrB protein, and MsrB mRNA in liver and kidney tissues of
both WT and MsrA-/- mouse strains. Whereas no significant protein-MetO
could be detected in tissue proteins of young mature mice grown on a
selenium-adequate diet, growth on the SD diet led to substantial
accumulations of MetO in proteins and also of protein carbonyl
derivatives in the liver, kidney, cerebrum, and cerebellum,
respectively. In addition, accumulation of protein-MetO derivatives
increased with age in tissues of mice fed with a selenium-adequate
diet. It should be pointed out that even though the total Msr level is
at least 2-fold higher in WT than in MsrA-/- mice, SD diet causes an
equal elevation of protein-MetO (except in brain cerebellum) and
carbonyl levels in both strains, suggesting involvement of other
selenoproteins in regulation of the level of cellular protein-MetO
accumulation. Furthermore, the development of the "tip-toe" walking
behavior previously observed in the MsrA-/- mice occurred earlier when
they were fed with the SD diet.
PMID: 12792026 [PubMed - indexed for MEDLINE]
FULL TEXT
http://www.pnas.org/cgi/content/full/100/13/7486
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