Binding of Chromium(III) to Transferrin Could Be Involved in Detoxification of Dietary Chromium(III) Rather than Transport of an Essential Trace Element. (20th May 2016)

• Record Type: Journal Article
• Authors: Levina, Aviva; Pham, T. H. Nguyen; Lay, Peter A.
• Is Part Of: Angewandte Chemie. Volume 128:Number 28(2016)
• Page Start: 8236
• Page End: 8239
• Publication Date: 2016-05-20
• Subjects: Chrom -- Metallhomöostase -- Spurenelemente -- Toxizität -- Transferrin; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201602996
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Cr III binding to transferrin (Tf; the main Fe III transport protein) has been postulated to mediate cellular uptake of Cr III to facilitate a purported essential role for this element. Experiments using HepG2 (human hepatoma) cells, which were chosen because of high levels of the transferrin receptor, showed that Cr III binding to vacant Fe III ‐binding sites of human Tf effectively blocks cellular Cr III uptake. Through bio‐layer interferometry studies of the Tf cycle, it was found that both exclusion and efflux of Cr2 III Tf from cells was caused by 1) relatively low Cr2 Tf affinity to cell‐surface Tf receptors compared to Fe2 Tf, and 2) disruption of metal release under endosomal conditions and post‐endosomal Tf dissociation from the receptor. These data support mounting evidence that Cr III is not essential and that Tf binding is likely to be a natural protective mechanism against the toxicity and potential genotoxicity of dietary Cr through blocking Cr III cellular accumulation.