Figure 1.
Scheme of the anti-hepcidin activity of heparin. In the physiological pathway, the binding of BMP6 causes the phosphorylation of Type I receptor by Type II receptor, which phosphorylates SMAD1/5/8 that associates with SMAD4, and the complex enters the nucleus to bind to the responsive element on the hepcidin promoter. The anti-hepcidin activity of heparin is thought to act by sequestering BMP6 and interfering with its binding to the receptors.