The role of alpha-hemoglobin stabilizing protein in redox chemistry, denaturation, and hemoglobin assembly.
Hemoglobin biosynthesis in erythrocyte precursors involves several steps. The correct ratios and concentrations of normal alpha (alpha) and beta (beta) globin proteins must be expressed; apoproteins must be folded correctly; heme must be synthesized and incorporated into these globins rapidly; and the individual alpha and beta subunits must be rapidly and correctly assembled into heterotetramers. These events occur on a large scale in vivo, and dysregulation causes serious clinical disorders such as thalassemia syndromes. Recent work has implicated a conserved erythroid protein known as Alpha-Hemoglobin Stabilizing Protein (AHSP) as a participant in these events. Current evidence suggests that AHSP enhances alpha subunit stability and diminishes its participation in harmful redox chemistry. There is also evidence that AHSP facilitates one or more early-stage post-translational hemoglobin biosynthetic events. In this review, recent experimental results are discussed in light of several current models describing globin subunit folding, heme uptake, assembly, and denaturation during hemoglobin synthesis. Particular attention is devoted to molecular interactions with AHSP that relate to alpha chain oxidation and the ability of alpha chains to associate with partner beta chains.
Mollan
Todd L
TL
Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251-1892, USA.
Yu
Xiang
X
Weiss
Mitchell J
MJ
Olson
John S
JS
D000818:Animals; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D018832:Molecular Chaperones / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding; D017433:Protein Structure, Secondary
C468768:AHSP protein, human; C511177:Ahsp protein, mouse; D001798:Blood Proteins; D006454:Hemoglobins; D018832:Molecular Chaperones