Transferrin synthesized in cultured human fibroblasts is associated with tubulins and has iron binding capacity

In a previous report, using immunocytochemical and fluorescence-labeling techniques, we demonstrated that transferrin is synthesized in cultured human fibroblasts and that it is associated with tubulins in the cells. These morphological findings led us to attempt to elaborate those issues in more detail by biochemical methods. In this report, we were able to prove the association of transferrin produced in cells with tubulins. In addition, the transferrin associated with tubulins was found to bind to iron. These results suggest that endogenous transferrin plays a role in preventing damage caused by free radicals which can be induced by the interaction of iron with the hydrogen peroxide produced in cells.