Peroxiredoxin -2: Oligometric characterization of a putative biomarker of oxidative stress in the blood storage scenario
Author(s)
Blasi, Barbara
Date Issued
April 12, 2012
Type
Doctoral Thesis
Abstract
Several researches on aging red blood cells (RBCs) revealed that RBC membrane proteins undergo a number of irreversible alterations, mainly due to oxidative stress. The individuation of proteins to be used as indicators of irreversible RBC injury and to be proposed as candidate biomarkers of oxidative damage or aging status during blood storage is therefore of great interest. We performed proteomic analysis of the membranes of RBCs during various storage periods under blood bank conditions. During storage, a progressive linkage of typical cytosolic proteins to the membrane was detected, including both antioxidant and metabolic enzymes (catalase, peroxiredoxin-2 [PrxII], and 2,3-bisphosphoglycerate-mutase. The detailed analysis of these protein associations to the membrane of aged RBCs allowed Prx2 to be suggested as a potential RBC oxidative stress marker. Since the oligomeric status of the Prx II protein is strictly related to its function, we decided to investigate the structure switches as results of storage. Cytosol and membrane ghosts of both fresh erythrocytes and 28-day stored erythrocytes were analyzed by proteomics tools. In fresh red blood cells PrxII exhibits four different oligomeric states in cytosol, whereas no PrxII complexes are in the membrane. In the highest molecular weight PrxII complex (440 kDa) it has been found that decameric PrxII is associated with tetrameric catalase. Upon oxidative stress (28-day storage), the CAT-PrxII hetero-oligomeric complex at 440 kDa is converted to a higher molecular weight structure (480 kDa) due to the presence therein of cross-linked species of PrxII and hemoglobin. Oxidized red cell membranes contained the CAT-PrxII complex detected in 0-day cytosol as a consequence of protein recruitments induced by oxidative stress. Our results contribute to clarify structural and functional switching of peroxiredoxin II in erythrocytes under standard blood bank conditions.
Additional information
Dottorato d ricerca in Genetica e biologia cellulare
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