DETYROSINATION OF TUBULIN AND Na+,K+-ATPase ACTIVITY IN HYPERTENSIVE PATIENTS ERYTHROCYTES

AMAIDEN R; RIVELLI J; SANTANDER V; MONESTEROLO N; FERNANDEZ A; ARCE C; CASALE C

CARLOS PAZ. CORDOBA

Congreso; SAIB 2008; 2008

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 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 of hypertensive patients (MTHP). Recently we demonstrated that the MTHP is increased and provokes a decrease in the Na+, K+-ATPase activity. In this work we show that in hypertensive patients: a) the detyrosinated tubulin is increased in a higher proportion than the other tubulin isotype, b) the increase in the detyrosination of tubulin correlates with the formation of more stable microtubules in erythrocytes of hypertensive patients, c) the low levels of tubulin tyrosination is due to lower tubulin tyrosine ligase activity and this is correlated with a decrease in the amount of the enzyme in the red blood cells from patients with hypertension d) in vitro experiments showed that low levels of tubulin tyrosination affects Na+,K+-ATPase activity. These results show that tubulin of hypertensive patients has at least one difference in the composition of isoespecies tubulin that is involved in the regulation of the Na+, K+-ATPase activity.