Band 3 tyr-phosphorylation in human erythrocytes from non-pregnant and pregnant women

Abstract

Pregnancy is associated with changes in circulating red blood cells, mainly involving band 3 protein and membrane lipid peroxidation. Membrane band 3 is a multifunctional protein containing four Tyr-phosphorylatable residues which modulate the physiological status of erythrocytes by regulating glycolysis, cell shape and membrane transport. Erythrocytes from nine pregnant and 12 age-matched non-pregnant healthy women were subjected to oxidative and hyperosmotic stress conditions and the extent of band 3 Tyr-phosphorylation and membrane Syk recruitment as a membrane marker were evaluated. Results indicated that, in pregnancy, red blood cells show a decrease in band 3 Tyr-phosphorylation and a clear-cut rearrangement of band 3 protein within the membrane. In fact, band 3 shows a decrease in high molecular weight aggregates (HMWA), with different subdivision between Triton-soluble and -insoluble compartments, and an increase in proteolytic fragments. In conclusion, it is demonstrated that pregnancy is associated with membrane adjustments which reduce the sensitivity of erythrocytes to both oxidative and osmotic stress. Band 3 Tyr-phosphorylation is proposed as a new parameter in the evaluation of erythrocyte membrane arrangement.

Inositol administration reduces oxidative stress in erythrocytes of patients with polycystic ovary syndrome

“…We have recently demonstrated that enhanced ROS production in endometriotic patients is correlated with both increased diamide-induced erythrocyte band 3 Tyr-P level and high DGSH, indicating that OS induces structural modifications of membranes (22). Diamideinduced OS in human erythrocytes causes net membrane rearrangement with band 3 aggregate formation (16,18) and kinase (37) and phosphatase (38) recruitments, all leading to a triggering of band 3 Tyr-P levels (20). In PCOS, RBC are much more sensitive to diamide treatment and, consequently, band 3 Tyr-P reaches levels two or three times higher than those of controls, probably due to an altered redox system, predisposing membrane proteins to be more markedly oxidized.…”

“…Oxidation can lead to inter-and/or intramolecular cross-linking, thus inducing protein degradation (14,15), clustering (16,17,18), and enzyme inactivation (18,19).…”

“…Alterations in band 3 Tyr-P levels represent preexisting modifications of membrane status, like that observed in glucose-6-phosphate dehydrogenase (G6PD)-deficient patients (18,21) suffering from chronic impairment of antioxidant defenses or in endometriotic women (22) with systemic inflammation. Diamide, a mild oxidant, affects the sulfhydryl groups of cysteines by inducing disulfide bond formation and triggers band 3 Tyr-P (16,17,18,20,21,22), which is a useful parameter in the evaluation of oxidation-related damage to cells (18,21,22). We also observed that, while diamide treatment reduced total glutathione (GSH) contents detectable in the cytosol of endometriotic patients, normal subjects were unaffected, and the differences between GSH content before and after diamide treatment were defined as DGSH, an additional parameter of inflammatory status in endometriosis (22).…”

Exhaustive Running Exercise Induce Tyrosine Phosphorylation of Band 3 in Rat Erythrocytes

“…In vitro studies by Philip S. Low et al showed that tyrosine phosphorylation of band-3 markedly reduces its affinity for ankyrin, leading to release of band-3 from the spectrin/actin membrane skeleton and enhancing the lateral mobility of band-3 in the bilayer [49]. Indeed, ankyrin docks in close proximity to the band-3 cytoplasmic domain tyrosine phosphorylation sites, and non-phosphorylated band-3 appears to be less prone to forming high-molecular-mass aggregates [21,51,52]. The elevated phosphorylation of oxidized/oligomeric band-3 accompanied by the appearance of oxidative damage observed in this study supports the hypothesis that, in exhaustive exercise RBCs, a fraction of band 3 molecules are prone to being oxidatively clustered and tyrosine phosphorylated.…”

Evaluation of erythrocyte band 3 phosphotyrosine level, glutathione content, CA-125, and human epididymal secretory protein E4 as combined parameters in endometriosis

“…A marked increase in membrane protein Tyr-P levels, undetectable in resting conditions (17), may occur when several compounds, such as N-ethylmaleimide (18) and vanadate (18), either directly affect Tyr-protein phosphatase activity or induce oxidative (17)(18)(19)(20)(21)(22) stress. However, in normal red blood cells (RBCs), when band 3 Tyr-P is triggered, it is closely controlled and, consequently, cannot increase beyond limits determined by each specific effector used (18)(19)(20). What makes this level shift up or down is an alteration in RBC, as in pathological and/or physiological conditions.…”