THE PROCESS OF CELLULAR UPTAKE OF IRON FROM TRANSFERRIN - A COMPUTER-SIMULATION PROGRAM

In an attempt to improve our understanding of the complex interplay be tween cell compartments and chemical species during cellular uptake of iron from transferrin, we designed a computer simulation program base d on current models of receptor-mediated endocytosis and pinocytosis. The program calculates and visualizes, as a function of time, the chan ges in transferrin, apotransferrin, and iron concentrations occurring in all relevant cellular compartments during cellular iron acquisition from transferrin. Simulation of literature data showed that the progr am generates results that are in accordance with experimental data. Fu rthermore, from measurements of the uptake of [carboxyl-C-14]dextran w e could utilize the program to suggest rate constants characteristic f or the pinocytic process in rat reticulocytes. Moreover, simulations i ndicate that the apparent difference in the iron uptake process observ ed between reticulocytes and hepatocytes may be explained by the contr ibution made by pinocytosis to the iron uptake process. Finally, the p resent program should have potential as an educational tool during int roduction to the field of receptor-mediated endocytosis in general and to cellular iron metabolism in particular.