Final answer:
Ferroportin is the transporter that moves ferrous iron (Fe²+) from mucosal cells of the duodenum into the plasma, where it is bound to transferrin for transport throughout the body.
Step-by-step explanation:
The ferroportin transporter, also referred to as ferroportin itself, plays a crucial role in the absorption and transport of iron within the human body. After iron is absorbed into the mucosal cells of the duodenum, it can bind to the storage protein ferritin. When needed, iron is then transported out of these cells into the blood via the ferroportin transporter. In the plasma, iron is typically found bound to transferrin, which carries it through the bloodstream to various tissues. Transferrin binds iron in its ferric state (Fe³+), but the ferrous iron (Fe²+) absorbed by mucosal cells is rapidly oxidized to Fe³+ once it enters the plasma. This process is crucial for maintaining the body's iron homeostasis and is especially important in situations where iron demand is increased, such as during erythropoiesis stimulated by erythropoietin (EPO).