MEMBRANE TUBULIN OF HYPERTENSIVE PATIENTS ERYTHROCYTES

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

Mar del plata

Congreso; SAIB 2007; 2007

SAIB

The acetylated tubulin associated to the plasma membrane is able to inhibit the Na+,K+-ATPase activity in different cells types including human erythrocytes. Hypertensive patients (HP) accumulates Na+ in the erythrocytes because in these cells the Na+,K+-ATPase is inhibited. In order to determine if tubulin is involved in the enzyme inhibition in these patients, we studied the erythrocytes membrane tubulin in hypertensive patients (MTHP). The results of this work show that: a) the erythrocytes plasma membrane of HP possess 80% more tubulin and the Na+,K+-ATPase activity is 50 % lower than the controls, b) MTHP increase, although the tubulin isotypes ratios stay unaltered, c) the immunoprecipitation experiments show that tubulin coprecipitates with another protein of MW ~ 110 kDa of the human erythrocytes plasma membrane from HP, and d) the HP erythrocytes pre-treated with taxol show higher quantities of tubulin in the 100.000 x g sediment, correspond to cytosolic fraction. Taken together, these results show that in HP the membrane tubulin is implicated in the regulation of the Na+,K+-ATPase activity of human erythrocytes, not only by its association to plasma membrane, but the formation of a macromolecular structure that allows the tubulin associates to the membrane and inhibits the enzymatic activity.