monensin and 3-hydroxyaspartic-acid

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 L-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.

Topics: Acetylation; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Aspartic Acid; Astrocytes; Cells, Cultured; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Glucose; Glutamic Acid; Ionophores; Mice; Monensin; N-Methylaspartate; Sodium-Potassium-Exchanging ATPase; Tubulin