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

In an attempt to improve our understanding of the complex interplay between cell compartments and chemical species during cellular uptake of iron from transferrin, we designed a computer simulation program based on current models of receptor-mediated endocytosis and pinocytosis. The program calculates and visualizes, as a function of time, the changes 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 program generates results that are in accordance with experimental data. Furthermore, from measurements of the uptake of [carboxyl-C-14]dextran we could utilize the program to suggest rate constants characteristic for the pinocytic process in rat reticulocytes. Moreover, simulations indicate that the apparent difference in the iron uptake process observed between reticulocytes and hepatocytes may be explained by the contribution made by pinocytosis to the iron uptake process. Finally, the present program should have potential as an educational tool during introduction to the field of receptor-mediated endocytosis in general and to cellular iron metabolism in particular.