Iron is an essential trace metal that is needed by all cells. Iron is taken into the cells via a two-component system. The transferrin receptor is a membrane protein that is continually endocytosed and recycled back to the plasma membrane. Transferrin is a soluble protein that circulates in the bloodstream and binds free iron at neutral but not acidic pH. At neutral pH, circulating transferrin can bind to the transferrin receptor only if transferrin has iron bound to it. However, at acidic pH, transferrin binds the transferrin receptor even in the absence of iron. Describe the process of iron uptake and the fate of the receptors.
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Step 1: Transferrin, a soluble protein, circulates in the bloodstream and binds free iron at neutral pH. Show more…
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Although essential, iron is also potentially toxic. It is maintained at optimal levels in mammalian cells by the actions of three proteins. Transferrin binds to extracellular iron ions and carries it within the bloodstream; the transferrin receptor binds iron-loaded transferrin and brings it into the cell; and ferritin binds iron within the cell to provide an intracellular storage site. Both ferritin and the transferrin receptor are regulated by mechanisms that are similar and complementary. Do a bit of research and describe in general how the concentrations of ferritin and transferrin receptor are regulated by iron levels. You will (hopefully) find that the two are regulated by a similar mechanism, but in an opposite fashion. Explain how this opposite regulation in response to iron levels makes biological sense.
Adi S.
When iron stores are low, the relationship between the transferrin receptor and ferritin? The expression of both the transferrin receptor and ferritin increases, to promote the uptake of iron into the cells. The expression of both the transferrin receptor and ferritin decreases to maximize the amount of iron circulating in the blood. The expression of the transferrin receptor increases to maximize the uptake of iron from the blood into the cells, and the expression of ferritin decreases. The expression of the transferrin receptor decreases and the expression of ferritin increases so iron remains in the cell.
Dominador T.
Iron Deficiency? Iron is essential to most life forms and to normal human physiology. It is an integral part of many proteins and enzymes that maintain good health. Recommendations for iron are provided in Dietary Reference Intakes, developed by the Institute of Medicine of the National Academy of Sciences. The recommended dietary allowance (RDA) of iron for adult females under the age of 51 years is 18 milligrams (mg) per day. A hypothesis test is to be performed to decide whether adult females under the age of 51 years are, on average, getting less than the RDA of $18 \mathrm{mg}$ of iron.
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