DIABETIC PATIENTS CONTAIN HIGHER PROPORTION OF TUBULIN IN ERYTHROCYTES MEMBRANE.

RIVELLI J; AMAIDEN R; SANTANDER V; MONESTEROLO N; PREVITALI G; PIE-JUSTE J; ARCE C.; CASALE C

Mar del plata

Congreso; SAIB 2007; 2007

SAIB

Part of cytosolic tubulin is associated to plasma membrane and inhibit the Na+,K+-ATPase. We demonstrated that the ATPase inhibition by tubulin in vitro is reverted by glutamate and reversibly inhibited by glucose. In erythrocytes of diabetics patients (DP), the Na+,K+-ATPase is inhibited. To determinate if tubulin is involved in the inhibition of the enzyme in these patients, we studied the plasma membrane tubulin of diabetic patient’s erythrocytes. In this work we show that: a) erythrocytes of DP possess 120 % more tubulin in the plasma membrane than the control patients, b) the DP erythrocytes pre-treated with taxol show higher quantities of tubulin in the 100.000 x g sediment, correspond to citosolic fraction, c) confocal immunofluorescence images show that the DP erythrocytes do not have the circular structure of microtubules present in normal erythrocytes. These results were similar to those seen when normal erythrocytes were treated with glucose or sorbitol 20 mM. On the basis of these results, we determinates the effect of glucose on microtubule formation in COS and CAD cells. Glucose and sorbitol increased the microtubule and tubulin/Na+,K+-ATPase complex formation. These results show that membrane tubulin is involved in the regulation of Na+,K+-ATPase activity from DP erythrocytes, probably by the high glucose concentration in blood serum.