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

CAMPETELLI AN; PREVITALI G; MONESTEROLO NE; ARCE C.A; BARRA HS; CASALE CH

Iguazú, Misiones

Congreso; Sociedad Argentina de investigación Bioquímica y Biología Molecular,; 2004

SAIB

It was previously reported that Na+,K+-ATPase in membranes of brain and cultured astrocytes interacts with tubulin and thatthis 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 hydrofobic 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 demonstrated 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 hidher when the tubulin preparation contained higher proportion of of acetylated tubulin 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 acetylatedd tubulin associated with the enzyme. Addition of 1 mM 2-deoxy-glucose (inhibitor of the glucose transport) after D-Glucose treatment reversed the effect of D-Glucose. These results indicate that the H+-ATPase activity of S. cerevisiae is modulated by the association/dissociacition of (acetylated tubulin- H+-ATPase) complex.