PHOSPHORYLATION OF Cl-, HCO3--STIMULATED Mg2+-ATPase OF PLASMA MEMBRANES OF CARP (Cyprinus carpioL.) BRAIN SENSITIVE TO GABAА-ERGIC LIGANDS
Institute of General Pathology and Phathophysiology of Russian Academy of Medical Sciences, Moscow, Russia;
Phosphorylation of the sensitive to GABAA-ergic ligands Cl-, HCO3--stimulated Mg2+-ATPase of the plasma membranes from fish brain by [?-32Р]АТР was investigated in the presence of Mg2+. It was established, that formation of the phosphoprotein at 0–1 °C is dependent on time incubation and concentration of Mg2+ in the incubation medium. Hydroxylamine (50 mM) and pH (10) completely inhibited formation of phosphorylated intermediate. Ions of Cl- (10 mM)+HCO3- (2 mM) and also GABA (1–100 ?M) dephosphorylated the enzyme. The dephosphorylating effect of GABA on the membrane samples did not appear in the presence of bicuculline. o-Vanadate (10 ?M) eliminates the dephosphorylating effect of anions and GABA on the phosphoprotein. It was established by SDS-PAAG electrophoresis and autoradiographia that investigated phosphorylation and GABAA-induced dephosphorylation is performed by the protein with molecular weight ~56 kDa. Such molecular weight has a subunit which forms oligomer composition of the sensitive to GABAA-ergic ligands Cl-, HCO3--ATPase from fish brain. The obtained data demonstrated that Cl, HCO3-ATPase from fish brain can be directly phosphorylated by [?-32Р]АТР in the presence of Mg2+ and forms the phosphorylation intermediate.
Key words: fish, brain, plasma membranes, Cl-, HCO3--ATPase, GABA, bicuculline, phosphorylation, autoradiographya, molecular mass, o-vanadate, hydroxylamine.
Published at the site: 2006-09-25
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