Membrane-bound serine protease (PubMed:18976966, PubMed:20518742, PubMed:25156943, PubMed:25588876). Through the cleavage of cell surface hemojuvelin (HJV), a regulator of the expression of the iron absorption-regulating hormone hepicidin/HAMP, plays a role in iron homeostasis (PubMed:18408718, PubMed:18976966, PubMed:25156943). {ECO:0000269|PubMed:18408718, ECO:0000269|PubMed:18976966, ECO:0000269|PubMed:20518742, ECO:0000269|PubMed:25156943, ECO:0000269|PubMed:25588876, ECO:0000303|PubMed:25156943}. This is the function of TMPRSS6 (transmembrane serine protease 6, Ensembl gene identifier ENSG00000187045).