INTERACTION TUBULIN-NA,K-ATPASE IN HUMAN ERYTHROCYTES

SANTANDER VERONICA; RIVELLI JUAN; AMAIDEN RAFAELA; CAMPETELLI ALEXIS; FERNANDEZ ADRIANA; PREVITALI GABRIELA; CARLOS ARCE; CASALE CESAR

Villa Giardino. Córdoba.

Congreso; XVI Jornadas Científicas. Sociedad de Biología de Córdoba.; 2007

Acetylated tubulin is assosiates with plasma membrane Na+,K+ ATPase inhibiting the enzymatic activity, in neural and non-neural cells. We found that this association is present in membrane of human erythrocytes (MHE). Were determinated in MHE: 1)different tubulin isotypes, 2) hydrophobic propierties of the acetylated tubulin isotypes, 3)the capacity of the membrane of converted hydrophilic acetylated tubulin in hydrophobic acetylated tubulin, 4) the effect of exogen tubulin on Na+,K+ ATPase activity of the membrane.  Results indicated that MHE contain 4-fold less tubulin that brain plasma membrane and it 50% less acetylated. As others cells, the tubulin of MHE is a peripherical membrane protein, probably by association with membrane protein. MHE were able to associated hydrophilic tubulin of brain rat and converted in hydrophobic component, and this association inhibit the Na+,K+ ATPase activity of the MHE. Double inmunofluorescence observed by confocal microscopy indicated that tubulin and Na+,K+ ATPase co-localize at the periphery of human erythrocytes. Biochemical experiment using isolated human erythrocytes demonstrated that L-glutamate increase the Na+,K+ ATPase activity and decrease of the amount of acetylated tubulin of the MHE. This effect is reverted by glucose addition and monensin (Na+ ionophore) produce the similar effect that L-glutamate. These result show that the acetylated tubulin may by involved in the modulation of the control of Na+ and K+ transport in human erythrocytes by its interaction with ATPase.