ECTOPIC EXPRESSION OF NRAMP1 IN COS-1 CELLS MODULATES IRON ACCUMULATION

Nramp1 (natural resistance-associated macrophage protein) controls inn ate immunity and encodes a transporter of unknown function. Here we de scribe an antibody to Nramp1 displaying immunoreactivity towards a mat ure heavily glycosylated polypeptide of 90-100 kDa and a precursor for m of 45 kDa in macrophages. Ectopic expression of the Nramp1 cDNA in C OS-1 cells demonstrates that Nramp1 modulates cellular iron levels fol lowing loading with low molecular weight iron chelates. Surprisingly, Nramp1 does not enhance iron uptake, but expression is associated with reduced cellular iron loads. We propose Nramp1 may play a role in a s alvage pathway of iron recycling. (C) 1998 Federation of European Bioc hemical Societies.