Erythroferrone

Family with sequence similarity 132, member B
Identifiers
Symbols FAM132B ; C1QTNF15; CTRP15
External IDs OMIM: 615099 HomoloGene: 87245 GeneCards: FAM132B Gene
Orthologs
Species Human Mouse
Entrez 151176 227358
Ensembl ENSG00000178752 ENSMUSG00000047443
UniProt Q4G0M1 Q6PGN1
RefSeq (mRNA) NM_001291832 NM_173395
RefSeq (protein) NP_001278761 NP_775571
Location (UCSC) Chr 2:
238.16 – 238.17 Mb
Chr 1:
91.37 – 91.37 Mb
PubMed search
Erythroferrone
Identifiers
Symbol ERFE
Entrez 151176
HUGO 26727
OMIM 615099
RefSeq NM_001291832.1
UniProt Q4G0M1
Other data
Locus Chr. 2 q37.3

Erythroferrone is a protein hormone, abbreviated as ERFE, encoded in humans by the FAM132B gene. Erythroferrone is produced by erythroblasts, inhibits the action of hepcidin, and so increases the amount of iron available for hemoglobin synthesis.[1][2]

Discovery

It was identified in 2014 in mice where the transcript was found in bone marrow, encoded by the mouse Fam132b gene.[2] The homologous gene in humans is FAM132B and the sequence is conserved in other species. The protein is synthesized by erythroblasts and secreted.[2] This sequence had previously been found expressed in mouse skeletal muscle, called myonectin (CTRP15), and linked to lipid homeostasis.[3]

Structure

Erythroferrone in humans is transcribed as a precursor of 354 amino acids, with a signal peptide of 28 amino acids. The mouse gene encodes a 340 amino acid protein which is 71% identical.[2] Homology is greater at the C-terminal where there is a TNF-alpha-like domain.

Function

Erythroferrone is a hormone that regulates iron metabolism through its actions on hepcidin.[1] As shown in mice and humans, it is produced in erythroblasts, which proliferate when new red cells are synthesized, such as after hemorrhage when more iron is needed (so-called stress erythropoiesis).[4] This process is governed by the renal hormone, erythropoietin.[2]

Its mechanism of action is to inhibit the expression of the liver hormone, hepcidin.[4] This process is governed by the renal hormone, erythropoietin.[2] By suppressing this, ERFE increases the function of the cellular iron export channel, ferroportin. This then results in increased iron absorption from the intestine and mobilization of iron from stores, which can then be used in the synthesis of hemoglobin in new red blood cells.[2]

Mice deficient in the gene encoding erythroferrone have transient maturational hemoglobin deficits and impaired hepcidin suppression in response to plebotomy with a delayed recovery from anemia.[2]

In its role as myonectin, it also promotes lipid uptake into adipocytes and hepatocytes.[3]

Regulation

Synthesis of erythroferrone is regulated by erythropoietin binding to its receptor and activating the Jak2/Stat5 signaling pathway.[2]

Clinical significance

The clinical significance in humans is mostly unknown. From parallels in the mouse studies, there may be diseases where its function could be relevant. In a mouse model of thalassemia, its expression is increased, resulting in iron overload, which is also a feature of the human disease.[5] A role in the recovery from the anemia of inflammation in mice has been shown[6] and involvement in inherited anemias with ineffective erythropoiesis, anemia of chronic kidney diseases and iron-refractory iron-deficiency anemia has been suggested.[2][7]

References

  1. 1 2 Koury, M.J. "Erythroferrone: A Missing Link in Iron Regulation". The Hematologist. American Society of Hematology. Retrieved 26 August 2015.
  2. 1 2 3 4 5 6 7 8 9 10 Kautz L, Jung G, Valore EV, Rivella S, Nemeth E, Ganz T (Jul 2014). "Identification of erythroferrone as an erythroid regulator of iron metabolism". Nature Genetics 46 (7): 678–84. doi:10.1038/ng.2996. PMC 4104984. PMID 24880340.
  3. 1 2 Seldin MM, Peterson JM, Byerly MS, Wei Z, Wong GW (Apr 2012). "Myonectin (CTRP15), a novel myokine that links skeletal muscle to systemic lipid homeostasis". The Journal of Biological Chemistry 287 (15): 11968–80. doi:10.1074/jbc.M111.336834. PMC 3320944. PMID 22351773.
  4. 1 2 Kim A, Nemeth E (May 2015). "New insights into iron regulation and erythropoiesis". Current Opinion in Hematology 22 (3): 199–205. doi:10.1097/MOH.0000000000000132. PMC 4509743. PMID 25710710.
  5. Kautz L, Jung G, Du X, Gabayan V, Chapman J, Nasoff M, Nemeth E, Ganz T (Aug 2015). "Erythroferrone contributes to hepcidin suppression and iron overload in a mouse model of β-thalassemia". Blood. doi:10.1182/blood-2015-07-658419. PMID 26276665.
  6. Kautz L, Jung G, Nemeth E, Ganz T (Oct 2014). "Erythroferrone contributes to recovery from anemia of inflammation". Blood 124 (16): 2569–74. doi:10.1182/blood-2014-06-584607. PMC 199959. PMID 25193872.
  7. Cucuianu A, Patiu M, Trifa AP, Tomuleasa C, Dima D (Nov 2014). "Redistribution of iron towards deposits in erythroblastopenic anemia as a consequence of decreased erythroferrone production". Medical Hypotheses 83 (5): 530–2. doi:10.1016/j.mehy.2014.09.008. PMID 25267320.
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