Metabolic depletion inhibits the uptake of nontransferrin-bound iron by K562 cells

✍ Scribed by Jesus A. Gutierrez; Robin S. Inman; Thomas Akompong; Jianming Yu; Marianne Wessling-Resnick

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 161 KB
• Volume: 177
• Category: Article
• ISSN: 0021-9541
• DOI: 10.1002/(sici)1097-4652(199812)177:4<585::aid-jcp9>3.0.co;2-y

✦ Synopsis

The effect of metabolic inhibitors on nontransferrin bound iron transport by K562 cells was investigated. Incubation with 1 microM rotenone, 10 microM antimycin, or 0.5 mM 2,4-dinitrophenol effectively reduced ATP levels by approximately 50%. Both the rate and extent of Fe+3 uptake were impaired in ATP-depleted cells, which display a reduced Vmax for uptake. K562 cell ferrireductase activity was also lowered by metabolic inhibitors, suggesting that the apparent energy requirements for transport reside in the reduction of Fe+3 to Fe+2. However, ATP depletion was found to inhibit the rate and extent of Fe+2 uptake as well. Thus, the transbilayer passage of Fe+2 and/or Fe+3 appears to be an energy-requiring process. These features possibly reflect properties of the transport mechanism associated with a recently identified K562 cell transport protein, called SFT for "Stimulator of Fe Transport," since exogenous expression of its activity is also affected by ATP depletion.