REGULATION OF P-ATPases BY ACETYLATED TUBULIN: S. Cerevisiae H+-ATPase REGULATION MECHANISM.

CAMPETELLI A,; MONESTEROLO N; SANTANDER V; PREVITALI G; ARCE C; CASALE C

CARLOS PAZ. CORDOBA

Congreso; SAIB 2008; 2008

SAIB

Acetylated tubulin interacts with Na+/K+ATPase and as results of this interaction the ATPase results inhibited. We have been studying the regulation of several P-ATPases by tubulin. When a Ca2+ATPase enriched microsomal preparation is stimulated with calmodulin or ethanol, the Ca2+ATPase-Tubulin complex is dissociated and the ATPase is activated, similarly, when S. cerevisiae are incubated with glucose, the Tubulin-H+ATPase complex is dissociated. In all cases, when the stimuli are eliminated, the ATPase-tubulin complexes are restored and the enzymes are inhibited again. In the H+ATPase activation, tubulin degradation has been observed. The aim of this work is to demonstrate a protease involvement in this activation mechanism. In in vivo experiments using several protease inhibitors we found that tubulin proteolisys is mediated by a metalloprotease. Affinity chromatography showed that tubulin is able to retain a protease from a yeast citosolic extract and in a tubulin degradation assay using this tubulin retained protease, we obtained significative results. These yeast citosolic proteins retained by tubulin were identified by MALDI TOF, but any protease like protein was identified. Probably, this enzyme is not a citosolic protein, so next experiments are focalized in the screening of proteins from other sub cellular compartment.