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Lactoferrin activates plasma membrane oxidase and Na+/H+ antiport activity
I L Sun1, F L Crane, D J Morré
1Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Biochemical and Biophysical Research Communications
|April 15, 1991
Summary
Lactoferrin stimulates cell growth, potentially by influencing iron reduction and proton release at the cell membrane, rather than through traditional iron uptake. This suggests a novel mechanism for lactoferrin
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Lactoferrin is recognized as a potent cell growth stimulant.
- The precise mechanism underlying lactoferrin's proliferative effect remains unclear, as it is not traditionally associated with iron uptake via endocytosis.
Purpose of the Study:
- To investigate the non-endocytic mechanisms by which ferric lactoferrin promotes cell proliferation.
- To explore the role of lactoferrin in cellular redox reactions and ion transport at the plasma membrane.
Main Methods:
- Assessing external ferrous chelate formation by K562 and HeLa cells in the presence of ferric lactoferrin.
- Measuring the reduction of external ferric iron by cells stimulated with ferric lactoferrin.
- Evaluating the stimulation of NADH oxidase activity in isolated rat liver plasma membranes by ferric lactoferrin.
- Quantifying amiloride-sensitive proton release from K562 cells induced by ferric lactoferrin.
Main Results:
- Ferric lactoferrin facilitated external ferrous chelate formation and ferric iron reduction by K562 and HeLa cells.
- Ferric lactoferrin stimulated NADH oxidase activity in rat liver plasma membranes.
- Ferric lactoferrin induced amiloride-sensitive proton release from K562 cells.
- These findings suggest ferric lactoferrin's involvement in plasma membrane redox reactions.
Conclusions:
- Ferric lactoferrin's proliferative effect may be explained by its participation in oxidoreduction reactions at the plasma membrane.
- This process could lead to the activation of the Na+/H+ exchange system, offering an alternative mechanism for growth stimulation.