REGULATION OF NA,K-ATPase BY DETYROSINATED TUBULIN. IMPLICANCE IN HYPERTENSIVE SUBJECTS

AMAIDEN MR; MONESTEROLO NE,; C H CASALE.; SANTANDER V

Mendoza

Congreso; SAIB 2012; 2012

SAIB

Balance between tyrosinated and detyrosinated tubulin is essential for the normal development of the cells. Previously we demonstrated that detyrosinated tubulin is increased in erythrocytes membranes of hypertensive subjects. On the other hand, there is known that in erythrocytes of hypertensive subjects the Na+,K+-ATPase (NKA) activity is decreased in a 50 % and that the activity of this enzyme can be inhibited by the formation of a complex between the NKA and tubulin. Although it is known that it is essential that tubulin must be acetylated to form the complex has not be studied if another postraslational modifications of tubulin, in particular detyrosinated tubulin, is involved in the above mentioned regulatory mechanism. In this work we demonstrate that the detyrosinated tubulin enhanced the inhibition of acetylated tubulin on the NKA activity and changes in levels of detyrosinated tubulin in the membrane produces modifications on the NKA activity. On the other hand, we show that the increase of detyrosinated tubulin in erythrocytes of hypertensive subjects would be a consequence of a decrease in the content and the activity of the enzyme tubulin tyrosine ligase but not tubulin tyrosine carboxipeptidase. In conclusion, the normal function of cycle of detyrosination/tyrosination has an important role in the regulation of the NKA activity, and then abnormalities in its cycle would be involved in the progression of different pathologies were NKA is implicated.