Work

Alternate iron transport pathway. Mobilferrin and integrin in K562 cells.

Year: 1994

Type: article

Abstract: A transferrin-independent iron transport system in cells containing transferrin receptors was described previously by several investigators. Prior studies did not identify the proteins involved in this alternate iron transport pathway. Using a human-derived erythroleukemia tissue culture line, iron-binding proteins were isolated from cytosol and cell membranes. The cytosol protein was soluble in 60% ammonium sulfate, had a molecular mass similar to mobilferrin (56 kDa), and reacted with anti-mobilferrin antibodies. The water-insoluble radiolabeled protein was solubilized with Nonidet P-40 and immunoprecipitated with monoclonal antibody against beta 3 human integrin. Pulse-chase studies suggested sequential passage of iron to integrin, mobilferrin, and ferritin, respectively. Thus, the alternate iron transport pathway contained proteins similar to those observed in intestinal cells which did not possess transferrin receptors on their absorptive surface. The alternate iron transport pathway is only partially shared with zinc and cadmium. Mobilferrin bound zinc and iron competitively, but the two metals were not transported competitively into K562 cells. Immunoprecipitates of integrin containing radiozinc were obtained with a monoclonal antibody against beta 1 human integrin. This suggested iron and zinc may utilize different integrins to passage the cell membrane.

Source: Journal of Biological Chemistry

DOI: 10.1016/s0021-9258(17)37263-0

Authors: M.E. Conrad, J.N. Umbreit, E.G. Moore, C. Uzel, M.R. Berry

Institution: University of South Alabama

Language: English

Topic: Iron Metabolism and Disorders

Subfield: Hematology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $3,430