1. An iron-regulated ferric reductase associated with the absorption of dietary iron.
- Author
-
McKie AT, Barrow D, Latunde-Dada GO, Rolfs A, Sager G, Mudaly E, Mudaly M, Richardson C, Barlow D, Bomford A, Peters TJ, Raja KB, Shirali S, Hediger MA, Farzaneh F, and Simpson RJ
- Subjects
- Amino Acid Sequence, Anemia enzymology, Animals, Cell Line, Cloning, Molecular, Cytochrome b Group chemistry, Cytochrome b Group genetics, DNA, Complementary, Duodenum enzymology, Enterocytes enzymology, Enterocytes metabolism, Enzyme Induction, Hypoxia, Intestinal Mucosa enzymology, Iron, Dietary administration & dosage, Male, Mice, Microvilli enzymology, Microvilli metabolism, Molecular Sequence Data, Nitroblue Tetrazolium metabolism, Oocytes, Oxidation-Reduction, Oxidoreductases chemistry, Oxidoreductases genetics, RNA, Messenger genetics, RNA, Messenger metabolism, Tetrazolium Salts metabolism, Thiazoles metabolism, Up-Regulation, Xenopus, Cytochrome b Group metabolism, Duodenum metabolism, Ferric Compounds metabolism, Intestinal Absorption, Intestinal Mucosa metabolism, Iron, Dietary metabolism, Oxidoreductases metabolism, Transfection
- Abstract
The ability of intestinal mucosa to absorb dietary ferric iron is attributed to the presence of a brush-border membrane reductase activity that displays adaptive responses to iron status. We have isolated a complementary DNA, Dcytb (for duodenal cytochrome b), which encoded a putative plasma membrane di-heme protein in mouse duodenal mucosa. Dcytb shared between 45 and 50% similarity to the cytochrome b561 family of plasma membrane reductases, was highly expressed in the brush-border membrane of duodenal enterocytes, and induced ferric reductase activity when expressed in Xenopus oocytes and cultured cells. Duodenal expression levels of Dcytb messenger RNA and protein were regulated by changes in physiological modulators of iron absorption. Thus, Dcytb provides an important element in the iron absorption pathway.
- Published
- 2001
- Full Text
- View/download PDF