Lpx1p serin protease participates in the glucose-induced S. cerevisiae H+-ATPase activation

CAMPETELLI ALEXIS; ORTIZ E.; MONESTEROLO NOELIA; AMAIDEN RAFAELA M; PREVITALI G; C CASALE

Puerto Madryn

Congreso; SAIB 2010; 2010

SAIB

In previous work we showed that acetylated tubulin interacts with some P-ATPases inhibiting their enzymatic activities. In S. cerevisiae, the plasma membrane H+-ATPase is inhibited by tubulin and, upon glucose addition, the ATPase is activated and the tubulin is dissociated. Recently, we have shown that the tubulin dissociation is caused by degradation of the membrane tubulin by a serin like protease. In this work we shows that the strain YOR084w, loosing a serin protease of 44 kDa and pI 8.4 is deficient in H+-ATPase activation and tubulin degradation when stimulated with glucose, indicating that this protease could be involved in the H+-ATPase activation mechanism. The complementation of the YOR084w strain with the wild type form of the gene LPX1 showed that glucose could activate the H+-ATPase activity through the degradation of membrane tubulin. These results demonstrate that glucose activates the plasma membrane H+-ATPase of S. cerevisiae in a mechanism which involves the hydrolysis of membrane tubulin by the action of Lpx1p which causes the dissociation of acetylated tubulin / H-ATPase complex.