NRAMP system

Cadmium, again with a much higher affinity to thiol compounds, is a toxic-only element. Only one case of Cd(II) as a trace element has been reported in the absence of Zn(II), Cd(II) was used by some diatoms in the active site of carbonic anhydrase (Lane and Morel 2000). Cd(II) enters the cell by (CorA- and NRAMP-like) uptake systems (Nies 1999), binds to thiol compounds (thereby exerting toxicity), and is then reexported by efflux systems (P-, CBA, or CDF type) (Nies 2003). 

In addition, recent developments in our understanding of iron uptake and transport provide strong evidence that these systems may also facilitate uptake and transport of lead. Recent smdies on the intestinal iron transporter, Nramp, suggest that this protein may also be responsible for uptake of lead from the intestines into the bloodstream (469). 

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