Comment on: PACE4 (PCSK6): another proprotein convertase linked to iron homeostasis?

We thank the authors of this letter[1][1] for their interest in our paper[2][2] and for their detailed analysis of the evidence for and against the proteases responsible for the cleavage of transferrin receptor-2 (TFR2) from the cell surface in hepatocytes and erythroid cells. Their hypothesis of