ACTIVATION OF THE ALDOSE REDUCTASE BY DIRECT INTERACTION WITH TUBULIN

RIVELLI JF; S PERETTI; SANTANDER V.; PREVITALI G; PRIMO E.; CASALE C. H.

Mendoza

Congreso; SAIB 2012; 2012

SAIB

Previously we demonstrate that high glucose concentrations induces polimerization of microtubules, formation of acetylated tubulin/Na+,K+-ATPase (NKA) complex and consequently inhibition of enzymatic activity. The increase in the content of microtubules is due to increased levels of sorbitol formed by the activation of the aldose reductase (AR). This enzyme forms a complex with tubulin, which result in the increase of AR activity. In this work we study the effect of the tubulina on the AR activity . For this, we purified tubulin, from rat brain, and AR, by expression of AKR1B1 (human AR) gen in E. coli BL21a strain to determine the interaction between both proteins and the effect on the enzymatic activity. The results indicate that: i) both proteins interact in direct form, ii) tubulin increases the AR activity more than seven times, iii) Tubulin has not effect when it is polymerized before interaction with AR, and iv) both tyrosine and nitrotyrosine are able to prevent in vitro the association between tubulin and AR and consequently the enzymatic activation. These results suggest that AR activity is regulated by direct interaction with tubulin and that the enzymatic activity is involved in the tubulina polymerization and regulation of NKA activity when the cells are submitted to high concentrations of glucose.