EFFECT OF GLUCOSE ON DISTRIBUTION AND
POSTRANSLATIONALMODIFICATIONS OFTUBULIN IN
ERYTHROCYTES
Nigra AD, Amaiden MR, Peretti SO, Rivelli JF, Monesterolo NE,
Casale CH, Santander VS.
Dpto. Biología Molecular. Universidad Nacional de Río Cuarto. Email:
anigra@exa.unrc.edu.ar
In this work distribution of different isotypes of tubulin in
erythrocytes treated with high glucose concentrations was analyzed.
Results shown that, in human erythrocytes, glucose induce
translocation of tubulin from sedimentable fraction to the
membrane. Similar results are observed inWistar 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 Na ,K -ATPase (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 theNKAactivity.
