Ferroportin mediates iron influx across the basolateral membrane of enterocytes Authored: Jassal, B, 2009-09-25 Edited: Jassal, B, 2009-08-21 Pubmed15692071 Pubmed17486601 Pubmed19452451 Reactome Database ID Release 43442368 Reactome, http://www.reactome.org ReactomeREACT_20531 Reviewed: He, L, 2009-11-12 The primary site for absorption of dietary iron is the duodenum. Ferrous iron (Fe2+) is taken up from the gut lumen across the apical membranes of enterocytes and released into the portal vein circulation across basolateral membranes.<br>The human gene SLC40A1 encodes a metal transporter protein MTP1 (also called ferroportin or IREG1). This protein resides on the basolateral membrane of enterocytes and mediates ferrous iron efflux into the portal vein (Schimanski LM et al, 2005). MTP1 colocalizes with hephaestin (HEPH) which stablizes MTP1 and is necessary for the efflux reaction to occur (Han O and Kim EY, 2007; Chen H et al, 2009). As well as the dudenum, MTP1 is also highly expressed on macrophages (where it mediates iron efflux from the breakdown of haem) and the placenta (where it may mediate the transport of iron from maternal to foetal circulation). It is also expressed in muscle and spleen.