Involvement of acetylated tubulin in the regulation of Na+,K+-ATPase activity in cultured astrocytes

The results presented support the view that the modulation of Na+,K+-ATPase activity in living cells involves the association/dissociation of acetylated tubulin with the enzyme. We found that the stimulation of Na+,K+-ATPase activity by glutamate correlates with decreased acetylated tubulin quantity associated with the enzyme. The effect of L-glutamate was abolished by the glutamate transporter inhibitor DL-threo-beta-hydroxyaspartate but was not affected by either specific agonists or antagonists. The effect of L-glutamate seems to be mediated by Na+ entry resulting from glutamate transport, since the Na+ ionophore monensin produced stimulation of Na+,K+-ATPase activity with concomitant decrease of acetylated tubulin quantity associated with the enzyme. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.