ASSOCIATION OF TUBULIN TO THE MEMBRANE: IMPACT ON DIABETES AND HYPERTENSION

C H CASALE.; A NIGRA; S PERETTI; M R AMAIDEN; N MONESTEROLO; G PREVITALI; V S SANTANDER

San Juan

Jornada; 2da Reunión Conjunta de Sociedades de Biología de la República Argentina; 2011

SBC

Acetylated tubulin is associated with the plasma membrane through binding to P-ATPase modifying the activity of enzymes. In our laboratory we have shown that in erythrocytes of hypertensive and diabetic patients tubulin membrane is increased by more than twice a migration from a sedimentable structure. This increase of membrane tubulin decreases the deformability of erythrocytes and inhibits the activity Na+,K+-ATPase. The effect of tubulin on the P-ATPase activity is dependent on membrane lipidic composition. In fact, in the presence of basic or neutral lipids the enzime activity is inhibited, but in the presence of acidic lipids is increased to 27 times. Based on this background was proposed for this work to study the mechanism of translocation of tubulin to the membrana and its effect on ATPase activity. In this paper we show that: 1 .- the glucose and increased content of microtubules produce migration of tubulin to the membrane in synergy, through a mechanism that involves the participation of aldose reductase, 2 .- glucose causes the deacetylation of tubulin and promotes their migration to the plasma membrane probably due to the dynamism of the microtubule, 3 .- erythrocytes of diabetic patients or normal subjects treated with high concentration of glucose found a fraction of tubulin sediments with lower sedimentation coefficient to that found in erythrocytes of control subjects or hypertensive. These results allow us to speculate that the migration of cytoplasmic tubulin to the membrane, in addition to the acetylation of tubulin, it is necessary a change in the dynamics of microtubules. Both diabetes and hypertension are the elements that contribute to the modification of microtubule dynamics, the first high concentrations of glucose and the second modification of different microtubule-associated proteins (MAPs) as previously reported.