title: Band 3 Erythrocyte Membrane Protein Acts as Redox Stress Sensor Leading to Its Phosphorylation by p (72) Syk.
abstract: In erythrocytes, the regulation of the redox sensitive Tyr phosphorylation of band 3 and its functions are still partially defined. A role of band 3 oxidation in regulating its own phosphorylation has been previously suggested. The current study provides evidences to support this hypothesis: (i) in intact erythrocytes, at 2 mM concentration of GSH, band 3 oxidation, and phosphorylation, Syk translocation to the membrane and Syk phosphorylation responded to the same micromolar concentrations of oxidants showing identical temporal variations; (ii) the Cys residues located in the band 3 cytoplasmic domain are 20-fold more reactive than GSH; (iii) disulfide linked band 3 cytoplasmic domain docks Syk kinase; (iv) protein Tyr phosphatases are poorly inhibited at oxidant concentrations leading to massive band 3 oxidation and phosphorylation. We also observed that hemichromes binding to band 3 determined its irreversible oxidation and phosphorylation, progressive hemolysis, and serine hyperphosphorylation of different cytoskeleton proteins. Syk inhibitor suppressed the phosphorylation of band 3 also preventing serine phosphorylation changes and hemolysis. Our data suggest that band 3 acts as redox sensor regulating its own phosphorylation and that hemichromes leading to the protracted phosphorylation of band 3 may trigger a cascade of events finally leading to hemolysis.
authors.affiliation: Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Pantaleo
authors.affiliation: Department of Oncology, University of Turin, 10126 Turin, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Ferru
authors.affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, 37134 Verona, Italy.
authors.forename: Maria Carmina
authors.initials: MC
authors.lastname: Pau
authors.affiliation: Department of Oncology, University of Turin, 10126 Turin, Italy.
authors.forename: Amina
authors.initials: A
authors.lastname: Khadjavi
authors.affiliation: Department of Molecular Biotechnology and Life Sciences, University of Torino, 10126 Turin, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Mandili
authors.affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, 37134 Verona, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mattè
authors.affiliation: Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Spano
authors.affiliation: Department of Medicine, Section of Internal Medicine, University of Verona, 37134 Verona, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: De Franceschi
authors.affiliation: Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy.
authors.forename: Proto
authors.initials: P
authors.lastname: Pippia
authors.affiliation: Department of Oncology, University of Turin, 10126 Turin, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Turrini
mesh_terms: D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction; D000072377:Syk Kinase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D047428:Protein Kinase Inhibitors; C454201:SLC4A1 protein, human; C000606896:SYK protein, human; D000072377:Syk Kinase