A newly identified ferritin L-subunit variant results in increased proteasomal subunit degradation, impaired complex assembly, and severe hypoferritinemia.

Autor: Shagidov D; Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Israel Institute of Technology-Technion, Haifa, Israel., Guttmann-Raviv N; Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Israel Institute of Technology-Technion, Haifa, Israel., Cunat S; Department of Hematology Biology, CHU and University of Montpellier, Hôpital Saint Eloi, Montpellier Cedex 5, France., Frech L; Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Israel Institute of Technology-Technion, Haifa, Israel., Giansily-Blaizot M; Department of Hematology Biology, CHU and University of Montpellier, Hôpital Saint Eloi, Montpellier Cedex 5, France., Ghatpande N; Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Israel Institute of Technology-Technion, Haifa, Israel., Abelya G; Department of Life Sciences, Marcus Family Campus, Ben-Gurion University of the Negev, Beer-Sheva, Israel., Frank GA; Department of Life Sciences, Marcus Family Campus, Ben-Gurion University of the Negev, Beer-Sheva, Israel.; Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva, Israel.; The National Institute for Biotechnology in the Negev - NIBN, Ben-Gurion University of the Negev, Beer-Sheva, Israel., Aguilar Martinez P; Department of Hematology Biology, CHU and University of Montpellier, Hôpital Saint Eloi, Montpellier Cedex 5, France., Meyron-Holtz EG; Laboratory of Molecular Nutrition, Faculty of Biotechnology and Food Engineering, Israel Institute of Technology-Technion, Haifa, Israel.
Jazyk: angličtina
Zdroj: American journal of hematology [Am J Hematol] 2024 Jan; Vol. 99 (1), pp. 12-20. Date of Electronic Publication: 2023 Oct 23.
DOI: 10.1002/ajh.27124
Abstrakt: Ferritin is a hetero-oligomeric nanocage, composed of 24 subunits of two types, FTH1 and FTL. It protects the cell from excess reactive iron, by storing iron in its cavity. FTH1 is essential for the recruitment of iron into the ferritin nanocage and for cellular ferritin trafficking, whereas FTL contributes to nanocage stability and iron nucleation inside the cavity. Here we describe a female patient with a medical history of severe hypoferritinemia without anemia. Following inadequate heavy IV iron supplementation, the patient developed severe iron overload and musculoskeletal manifestations. However, her serum ferritin levels rose only to normal range. Genetic analyses revealed an undescribed homozygous variant of FTL (c.92A > G), which resulted in a Tyr31Cys substitution (FTL Y31C ). Analysis of the FTL structure predicted that the Y31C mutation will reduce the variant's stability. Expression of the FTL Y31C variant resulted in significantly lower cellular ferritin levels compared with the expression of wild-type FTL (FTL WT ). Proteasomal inhibition significantly increased the initial levels of FTL Y31C , but could not protect FTL Y31C subunits from successive degradation. Further, variant subunits successfully incorporated into hetero-polymeric nanocages in the presence of sufficient levels of FTH1. However, FTL Y31C subunits poorly assembled into nanocages when FTH1 subunit levels were low. These results indicate an increased susceptibility of unassembled monomeric FTL Y31C subunits to proteasomal degradation. The decreased cellular assembly of FTL Y31C -rich nanocages may explain the low serum ferritin levels in this patient and emphasize the importance of a broader diagnostic approach of hypoferritinemia without anemia, before IV iron supplementation.
(© 2023 The Authors. American Journal of Hematology published by Wiley Periodicals LLC.)
Databáze: MEDLINE
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