IMR Press / FBL / Volume 15 / Issue 1 / DOI: 10.2741/3601

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.

Article
Alpha-hemoglobin stabilizing protein: molecular function and clinical correlation
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1 Department of Biochemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
Front. Biosci. (Landmark Ed) 2010, 15(1), 1–11; https://doi.org/10.2741/3601
Published: 1 January 2010
Abstract

The discovery of alpha-hemoglobin stabilizing protein (AHSP), a chaperone for free alpha-hemoglobin (alpha-Hb), has provided a satisfactory solution to the perplexing problem of balanced globin levels for Hb production in erythroid cells in the face of a two-fold excess of alpha-globin to beta-globin gene dosage. Unmatched alpha-Hb is unstable and precipitates onto membranes, where the released heme exerts oxidative damages resulting in ineffective erythropoiesis and hemolytic anemia, the underlying causes of pathology in the hereditary anemia of beta-thalassemia. The interaction of alpha-Hb with AHSP involves surfaces normally employed in binding to beta-Hb. However, a conformational change to the AHSP-bound alpha-Hb results in an oxidized heme, but in a pocket that is now less exposed to the outside environment, thereby protecting against both peroxide-induced heme loss and iron-induced redox reaction. Studies in both mice and humans indicate that reduction in AHSP can result in hematological pathology. Conversely, alpha-Hb variants that are compromised in their ability to bind with AHSP produce beta-thalassemia-like symptoms. Disease conditions like some forms of thalassemia that are directly associated with AHSP structural and/or functional defects can now be included within the category of chaperonopathies.

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