INTERACTION OF TUBULIN WITH H+-ATPase OF PLASMA MEMBRANE IN SACCHAROMYCES CEREVISIAE. INFLUENCE OF GLUCOSE UPTAKE.

ALEXIS N. CAMPETELLI; GABRIELA PREVITALI; NOELIA MONESTEROLO; CARLOS A. ARCE; HÉCTOR S. BARRA; CESAR CASALE

Iguazù,Misiones, Argentina

Congreso; SAIB 2004; 2004

Sociedad Argentina de Investigacion Bioquimica y Biologia Molecular

It was previously reported that Na+,K+-ATPase in membranes of brain and cultured astrocytes interacts with tubulin and that this interaction inhibits the enzyme activity. Dissociation of the tubulin/ Na+,K+-ATPase complex leads to activation of the enzyme and to a lesser amount of hydrophobic tubulin. In the present study we investigated the eventual interaction of tubulin with H+-ATPase in yeast membranes. We found that the acetylated tubulin is present in plasma membrane of yeast and interacts with H+-ATPase. We demonstrate that this interaction inhibits the enzyme activity. In effect, when isolated membranes were treated with tubulin purified from brain, we found inhibition of H+-ATPase in a degree that was higher when the tubulin preparation contained higher proportion of the acetylated isoform. It is known that H+-ATPase is activated by the addition of D-glucose into the culture medium. As expected, after treatment of the cells with glucose, we found an inverse correlation between the activation of H+-ATPase and the amount of acetylated tubulin associated with the enzyme. Addition of 1 mM 2-deoxy-D-Glucose (inhibitor of D-Glucose transport) after D-glucose treatment reversed the effects of DGlucose. These results indicate that the H+-ATPase activity of S. cerevisiae is modulated by the association/dissociation of (acetylated tubulin-H+-ATPase) complex..