Regulation of acetylated tubulin/Na +,K +-ATPase interaction by l-glutamate in non-neural cells: involvement of microtubules

• Published in: Biochimica et biophysica acta Vol. 1721; no. 1; pp. 185 - 192
• Main Authors: Casale, César H., Previtali, Gabriela, Serafino, Juan J., Arce, Carlos A., Barra, Héctor S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 18.01.2005
• Subjects: Acetylated tubulin/Na +,K +-ATPase complex; Acetylation; Amino Acid Transport System X-AG - physiology; Animals; Cell Line; Glutamic Acid - pharmacology; Humans; Microtubule; Microtubules - physiology; Nocodazole - pharmacology; Non-neural cell; Paclitaxel - pharmacology; Sodium - metabolism; Sodium-Potassium-Exchanging ATPase - metabolism; Tubulin - metabolism; Acetylated tubulin/Na +,K +-ATPase complex; Non-neural cell; Microtubule
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2004.11.003

A subpopulation of membrane tubulin consisting mainly of the acetylated isotype is associated with Na +,K +-ATPase and inhibits the enzyme activity. We found recently that treatment of cultured astrocytes with l-glutamate induces dissociation of the acetylated tubulin/Na +,K +-ATPase complex, resulting in increased enzyme activity. We now report occurrence of this phenomenon in non-neural cells. As in the case of astrocytes, the effect of l-glutamate is mediated by its transporters and not by specific receptors. In COS cells, the effect of l-glutamate was reversed by its elimination from culture medium, provided that d-glucose was present. The effect of l-glutamate was not observed when Na + was replaced by K + in the incubation medium. The ionophore monensin, in the presence of Na +, had the same effect as l-glutamate. Treatment of cells with taxol prevented the dissociating effect of l-glutamate or monensin. Nocodazole treatment of intact cells or isolated membranes dissociated the acetylated tubulin/Na +,K +-ATPase complex. The dissociating effect of nocodazol does not require Na +. These results indicate a close functional relationship among Na +,K +-ATPase, microtubules, and l-glutamate transporters, and a possible role in cell signaling pathways.