| First Author | Han J | Year | 2011 |
| Journal | PLoS One | Volume | 6 |
| Issue | 8 | Pages | e23800 |
| PubMed ID | 21886823 | Mgi Jnum | J:176157 |
| Mgi Id | MGI:5288559 | Doi | 10.1371/journal.pone.0023800 |
| Citation | Han J, et al. (2011) Iron Uptake Mediated by Binding of H-Ferritin to the TIM-2 Receptor in Mouse Cells. PLoS One 6(8):e23800 |
| abstractText | Ferritin binds specifically and saturably to a variety of cell types, and recently several ferritin receptors have been cloned. TIM-2 is a specific receptor for H ferritin (HFt) in the mouse. TIM-2 is a member of the T cell immunoglobulin and mucin domain containing (TIM) protein family and plays an important role in immunity. The expression of TIM-2 outside of the immune system indicates that this receptor may have broader roles. We tested whether ferritin binding to TIM-2 can serve as an iron delivery mechanism. TIM-2 was transfected into normal (TCMK-1) mouse kidney cells, where it was appropriately expressed on the cell surface. HFt was labeled with (55)Fe and (55)Fe-HFt was incubated with TIM-2 positive cells or controls. (55)Fe-HFt uptake was observed only in TIM-2 positive cells. HFt uptake was also seen in A20 B cells, which express endogenous TIM-2. TIM-2 levels were not increased by iron chelation. Uptake of (55)Fe-HFt was specific and temperature-dependent. HFt taken up by TIM-2 positive cells transited through the endosome and eventually entered a lysosomal compartment, distinguishing the HFt pathway from that of transferrin, the classical vehicle for cellular iron delivery. Iron delivered following binding of HFt to TIM-2 entered the cytosol and became metabolically available, resulting in increased levels of endogenous intracellular ferritin. We conclude that TIM-2 can function as an iron uptake pathway. |
