Iron Homeostasis/Ferroptosis Antibody Sampler Kit #36354

Ferroptosis is an iron-dependent form of regulated cell death associated with an increase in lipid peroxides (1,2). Free divalent ferrous iron (Fe²⁺) can lead to spontaneous lipid peroxidation through a Fenton reaction. Iron is a crucial element involved in various physiological processes, including the production of hemoglobin and mitochondrial function. Its regulation involves control of transport, absorption, utilization, and storage (3). The glycoprotein transferrin, primarily produced in the liver, is the major ferric iron (Fe³⁺) transport protein controlling iron transport in the blood (4). It binds Fe³⁺ ions in association with an anion, usually bicarbonate. The iron binding affinity of transferrin is pH-dependent. In a neutral pH environment, transferrin (apotransferrin) binds iron with high affinity to form iron-bound transferrin (holotransferrin). In an acidic pH environment, the affinity of iron bound to transferrin decreases, dissociating iron from holotransferrin and releasing it into the environment (5). Cellular update of iron is controlled by holotransferrin binding to transferrin receptors and taken up through receptor-mediated endocytosis.

Transferrin receptor 1 (CD71, TFRC) is a type II transmembrane receptor and carrier protein responsible for the uptake of cellular iron (6). Export of iron from the cell is controlled by ferroportin-1 (FPN1), also known as solute carrier family 40 member 1 (SLC40A1) or iron-regulated transporter 1 (IREG1), a multi-pass membrane protein that transports iron from the inside of the cell into the blood (7). Cellular storage and transport of iron are highly regulated processes (8).

Ferritin is a ubiquitous protein that sequesters iron in a non-toxic and bioavailable form. Ferritin forms a large holoenzyme consisting of ferritin heavy chain (FTH) and ferritin light chain (FTL), each having unique functions. FTHs catalyze the first step in iron storage, the oxidation of Fe²⁺, whereas FTLs promote the nucleation of ferrihydrite, enabling storage of Fe³⁺ (9). Ferritin levels can be controlled through ferritinophagy, a selective process of autophagy targeting ferritin.

Nuclear receptor coactivator 4 (NCOA4), also known as ARA70 or ELE1, which was initially discovered as a transcriptional coactivator of androgen receptor (10,11), also functions as an autophagy cargo receptor by shuttling ferritin to the lysosome to maintain iron homeostasis (12-14).

Six transmembrane epithelial antigen of the prostate 1 (STEAP1) is a transmembrane metalloreductase abundantly expressed in the prostate that reduces Fe³⁺ to Fe²⁺ and Cu²⁺ to Cu¹⁺ (15).

Divalent metal-ion transporter 1 (DMT1, SLC11A2, NRAMP2) is a transmembrane metal ion transport protein that plays critical roles in non-heme iron absorption in the intestine and iron acquisition by erythroid precursor cells (16,17). Following cellular iron uptake, DMT1 transfers Fe³⁺ from the endosomes to the cytoplasm. Import of iron to the mitochondria, which is required for cellular respiration, is mediated by the solute carrier proteins mitoferrin-1 (SLC25A37) and mitoferrin-2 (SLC25A28) (18). Overall, many of the proteins that regulate iron homeostasis can play a critical role in regulating iron-dependent processes, sensitivity to ferroptosis, and human disease (19,20).