EFFECT OF GLUCOSE ON TYROSINATION, DETYROSINATION, ACETYLATION AND DISTRIBUTION OF TUBULIN IN ERYTHROCYTES

A NIGRA; AMAIDEN MR; S PERETTI; RIVELLI JF; MONESTEROLO NE,; CASALE C. H.; SANTANDER V.

Mendoza

Congreso; SAIB 2012; 2012

SAIB

Previously we demonstrated that levels of membrane acetylated tubulin are increased in erythrocytes of diabetic subjects, this increase could be related with the inhibition of Na+,K+-ATPase (NKA) observed in these patients. In this work was analyzed distribution of different isotypes of tubulin in erythrocytes treated with high glucose concentrations. Results shown that, in human erythrocytes, glucose induce translocation of tubulin from sedimentable fraction to the membrane. Similar results are observed in Wistar rats injected with high glucose concentrations; in this case the maximum levels of tubulin in the membrane was reached during the peak of glycemia after the treatment. When the glycemia values return to his basal values, tubulin is relocated in the sedimentable fraction. Analysis of different tubulin isotypes in the membrane showed an increase of both detyrosinated and acetylated tubulin, whereas the tyrosinated tubulin is diminishes in this fraction. These results would explain the fact that in diabetic subjects NKA activity is decreased. On the other hand, analysis of tubulin content in sedimentable fraction in erythrocytes treated with nocodazol showed that tubulin is lost when cells are treated with glucose. These results suggest that microtubules are present in the sedimentable fraction and they are more dynamics in erythrocytes treated with glucose. In conclusion, glucose induces in mammals? erythrocytes a redistribution of tubulin and changes in the different isotypes, fact that might be related to the inhibition of the NKA activity.