ISSN:
1471-4159
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Medicine
Notes:
Abstract : Studies on iron uptake into the brain have traditionallyfocused on transport by transferrin. However, transferrin receptors are notfound in all brain regions and are especially low in white matter tracts wherehigh iron concentrations have been reported. Several lines of research suggestthat a receptor for ferritin, the intracellular storage protein for iron, mayexist. We present, herein, evidence for ferritin binding sites in the brainsof adult mice. Autoradiographic studies using 125I-recombinanthuman ferritin demonstrate that ferritin binding sites in brain arepredominantly in white matter. Saturation binding analyses revealed a singleclass of binding sites with a dissociation constant (KD)of 4.65 × 10-9M and a binding site density(Bmax) of 17.9 fmol bound/μg of protein. Binding of radiolabeled ferritin can be competitively displaced by an excess of ferritin but not transferrin. Ferritin has previously been shown to affect cellular proliferation, protect cells from oxidative damage, and deliver iron. The significance of a cellular ferritin receptor is that ferritin is capable of delivering 2,000 times more iron per mole of protein than transferrin. The distribution of ferritin binding sites in brain vis-à-vis transferrin receptor distribution suggests distinct methods for iron delivery between gray and whi
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1471-4159.1999.720868.x
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