Membrane skeletal protein S-glutathionylation and hemolysis in human red blood cells

In this work, protein–glutathione mixed disulfide formation in human red blood cells (RBCs) was evaluated in vitro by using the thiol-specific reagent diamide. We investigated what mechanism could lead to S-glutathionylation of membrane skeletal proteins, what are the main target proteins, and the correlation between protein S-glutathionylation and RBC hemolysis. Diamide caused a decrease in the reduced form of glutathione (GSH), which was accompanied by an increase in the basal level of glutathione disulfide (GSSG) and in S-glutathionylation of protein 4.2 and spectrin. The increase in membrane skeletal protein S-glutathionylation was correlated with a lower susceptibility of RBCs to osmotic hemolysis, suggesting that S-glutathionylation of protein 4.2 and spectrin could contribute to regulate RBC membrane stability.