MECHANISM INVOLVED IN THE REGULATION OF ATPASES ACTIVITIES BY INTERACTION WITH ACETYLATED TUBULIN

MONESTEROLO N.; CAMPETELLI A.; SANTANDER V.,; PREVITALI G.,; ARCE C.; CASALE C.

Mar del plata

Congreso; SAIB 2007; 2007

SAIB

In our laboratory we described that the activities of P-ATPases, (Na+,K+)-, H+- and Ca2+-ATPase of plasma membrane, could be regulated by a common effector: acetylated tubulin. This isotype of tubulin interacts with these three plasma membrane ATPases and inhibits their enzymes activities. For the three studied enzymes we found that: a) the acetylated group over the lysine 40 of á-tubulin is a requirement for the interaction, b) the stimulation of the ATPase activity by specific effectors involves the dissociation of the tubulin/ATPase complex and c) the acetylated tubulin associated to ATPases is a component of microtubules. In this work we describe new advances in the mechanism of the inhibition of H+- and Ca2+-ATPases by tubulin. These results shows that: a) the tubulin/H+-ATPase complex dissociation from yeast depends on the microtubules dynamism, b) in yeast membranes we demonstrate a tubulin degradation dependent on pH changes, c) the calmodulin should dissociates the tubulin/Ca2+-ATPase complex to activates the enzyme in plasma membrane vesicles from synaptosomes (PMVs), d) the PMCA activation by ethanol found in PMVs occurs in cultured cells.  These results gives new contributions to the role of the cytoskeleton in the regulation of the P-ATPases activities, moreover, the acetylated tubulin could be the endogenous inhibitor of these enzymes.