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Reduced utilization of selenium during evolution of mammals
Author(s) -
Lobanov Alexey,
Castellano Sergi,
Hatfield Dolph L.,
Gladyshev Vadim N.
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a105-e
Subject(s) - selenium , selenocysteine , selenoprotein , selenoprotein p , biology , invertebrate , cysteine , zoology , chemistry , biochemistry , ecology , enzyme , glutathione peroxidase , glutathione , organic chemistry
In mammals, selenium is transported from liver to various organs in the form of multiple selenocysteine (Sec) residues in Selenoprotein P (SelP). Here we report that SelP homologs occur in most animals, and that the number of Sec residues in this protein varies from zero to at least eighteen. Organisms inhabiting aquatic environments, such as fish, amphibians and certain invertebrates, possess particularly high numbers of Sec residues, whereas in terrestrial organisms these residues are often replaced with cysteine. The abundance of Sec residues in aquatic organisms correlates with the high level of selenium in their organs. In addition, large selenoproteomes are typical for these organisms. These data suggest that evolution from aquatic vertebrates to mammals was accompanied by decreased utilization of selenium. The process of reduced dependence on selenium is still active, and a combination of selenoproteome size and the number of Sec residues in SelP may serve as genomic marker of selenium utilization in animals. The trend towards reduced selenium utilization in mammals raises questions regarding the need to maximize selenoprotein expression by dietary supplements.