title: Peroxyl-oxidized erythrocyte membrane band 3 protein with anion transport capacity is degraded by membrane-bound proteinase.
abstract: Human red blood cells anion exchange protein (band 3) exposed to peroxyl radicals produced by thermolysis of 2,2'-azo-bis(2-amidinopropane) (AAPH) is degraded by proteinases that prevent accumulation of oxidatively damaged proteins. To assess whether this degradation affects anion transport capacity we used the anionic fluorescent probe 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-y) amino] ethanosulfonate (NBD-taurine). A decrease of band 3 function was observed after exposure to peroxyl radicals. In the presence of proteinase inhibitors the decrement of anion transport through band 3 was smaller indicating that removal achieved by proteinases includes oxidized band 3 which still retain transport ability. Proteinases recognize band 3 aggregates produced by peroxyl radicals as was evaluated by immunoblotting. It is concluded that decrease of band 3 transport capacity may result from a direct protein oxidation and from its degradation by proteinases and that band 3 aggregates removal may prevent macrophage recognition of the senescent condition which would lead to cell disposal.
authors.affiliation: Departamento de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso Chile.
authors.forename: Gloria
authors.initials: G
authors.lastname: Celedón
authors.forename: Gustavo
authors.initials: G
authors.lastname: González
authors.forename: Verónica
authors.initials: V
authors.lastname: Ferrer
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Lissi
mesh_terms: D000578:Amidines / Q000378:metabolism; D001457:Anion Exchange Protein 1, Erythrocyte / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000838:Anions / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D005456:Fluorescent Dyes; D006801:Humans; D017136:Ion Transport; D010069:Oxadiazoles; D016877:Oxidants / Q000378:metabolism; D010084:Oxidation-Reduction; D010447:Peptide Hydrolases / Q000378:metabolism*; D010545:Peroxides / Q000378:metabolism*; D011480:Protease Inhibitors / Q000494:pharmacology; D013654:Taurine / Q000031:analogs & derivatives*
chemical_list: D000578:Amidines; D001457:Anion Exchange Protein 1, Erythrocyte; D000838:Anions; D005456:Fluorescent Dyes; C027027:NBD-taurine; D010069:Oxadiazoles; D016877:Oxidants; D010545:Peroxides; D011480:Protease Inhibitors; D013654:Taurine; C049375:perhydroxyl radical; C046728:2,2'-azobis(2-amidinopropane); D010447:Peptide Hydrolases