Figure 4: Translational initiation of ferritin and TfR mRNA degradation are regulated by binding of IRP to IRE in response to availability of iron. (1) In the excess iron, IRP forms an open conformation and is not able to bind IRE, subsequently translation of ferritin gets initiated and degradation of exposed TfR mRNA takes place. (2) In iron starved cells, IRP attains a closed conformation and binds to IRE present on UTR of ferritin mRNA thus interferes with translation initiation and simultaneously stabilize TfR mRNA by binding UTR. (3) Binding affinity of IRP-IRE is attenuated in presence of chlamydia leading to lower expression of TfR and higher expression of FHC [27].