Mitoferrin 2, also known as MRS3/4 (mitochondrial RNA-splicing protein 3/4 homolog), mitochondrial iron transporter 2, NPD016, MRS4L or SLC25A28 (solute carrier family 25 member 28), is a 364 amino acid multi-pass membrane protein of the mitochondrial inner membrane that mediates iron uptake. Mitoferrin 2 is thought to play a role in heme synthesis of hemoproteins and iron-sulfur cluster assembly. Ubiquitously expressed, Mitoferrin 2 is found at high levels in skeletal muscle, heart, placenta, kidney, lung, liver, brain and pancreas. Mitoferrin 2 is a member of the mitochondrial carrier family and undergoes alternative splicing events to produce four isoforms. Mitoferrin 2 contains three solcar repeats and is encoded by a gene that maps to human chromosome 10q24.2.