Red Blood Cell Proteasome in Beta-Thalassemia Trait: Topology of Activity and Networking in Blood Bank Conditions

Proteasomes are multi-catalytic complexes with important roles in protein control. Their activity in stored red blood cells (RBCs) is affected by both storage time and the donor's characteristics. However, apart from their abundancy in the membrane proteome, not much is known about their topology, activity, and networking during the storage of RBCs from beta-thalassemia trait donors (beta Thal(+)). For this purpose, RBC units from fourteen beta Thal(+) donors were fractionated and studied for proteasome activity distribution and interactome through fluorometric and correlation analyses against units of sex- and aged-matched controls. In all the samples examined, we observed a time-dependent translocation and/or activation of the proteasome in the membrane and a tight connection of activity with the oxidative burden of cells. Proteasomes were more active in the beta Thal(+) membranes and supernatants, while the early storage networking of 20S core particles and activities showed a higher degree of connectivity with chaperones, calpains, and peroxiredoxins, which were nonetheless present in all interactomes. Moreover, the beta Thal(+) interactomes were specially enriched in kinases, metabolic enzymes, and proteins differentially expressed in beta Thal(+) membrane, including arginase-1, piezo-1, and phospholipid scramblase. Overall, it seems that beta Thal(+) erythrocytes maintain a considerable proteo-vigilance during storage, which is closely connected to their distinct antioxidant dynamics and membrane protein profile.

Automated summary

Proteasome activity in stored red blood cells is influenced by storage time and donor characteristics, with higher activity observed in cells from beta-thalassemia trait donors. During storage, proteasomes show a close connection with oxidative stress and interact with chaperones and calpains. The interactomes of beta-thalassemia trait donors are enriched in kinases, metabolic enzymes, and proteins differentially expressed in their membranes.