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In the yeast Saccharomyces cerevisiae, plasma membrane H + -ATPase is activated by d-glucose. We found that in the absence of glucose, this enzyme forms a complex with acetylated tubulin. Acetylated tubulin usu-ally displays hydrophilic properties, but behaves as a hydrophobic com-pound when complexed with H + -ATPase, and therefore partitions into a detergent phase. | iFEBS Journal Activation of the plasma membrane H -ATPase of Saccharomyces cerevisiae by glucose is mediated by dissociation of the H -ATPase-acetylated tubulin complex Alexis N. Campetelli1 Gabriela Previtali1 Carlos A. Arce2 Hector S. Barra2 and Cesar H. Casale1 1 Departamento de Biologia Molecular Facultad de Ciencias Exactas Fisico-Quimicas y Naturales Universidad Nacionalde Rio Cuarto Cordoba Argentina 2 Centro de Investigaciones en Quimica Biologica de Cordoba CIQUIBIC UNC-CONICET Departamento de Quimica Biologica Facultad de Ciencias Quimicas Universidad Nacionalde Cordoba Argentina Keywords glucose H -ATPase proton pump tubulin yeast Correspondence H. S. Barra Departamento de Quimica Biologica Facultad de Ciencias Quimicas Universidad Nacionalde Cordoba Ciudad Universitaria 5000-Cordoba Argentina Fax 54 3514334074 Tel 54 3514334168 E-mail hbarra@dqb.fcq.unc.edu.ar Received 29 July 2005 revised 2 September 2005 accepted 6 September 2005 doi 10.1111 j.1742-4658.2005.04959.x In the yeast Saccharomyces cerevisiae plasma membrane H -ATPase is activated by D-glucose. We found that in the absence of glucose this enzyme forms a complex with acetylated tubulin. Acetylated tubulin usually displays hydrophilic properties but behaves as a hydrophobic compound when complexed with H -ATPase and therefore partitions into a detergent phase. When cells were treated with glucose the H -ATP-ase-tubulin complex was disrupted with two consequences namely a the level of acetylated tubulin in the plasma membrane decreased as a function of glucose concentration and b the H -ATPase activity increased as a function of glucose concentration as measured by both ATP-hydrolyzing capacity and H -pumping activity. The addition of 2-deoxy-D-glucose inhibited the above glucose-induced phenomena suggesting the involvement of glucose transporters. Whereas total tubulin is distributed uniformly throughout the cell acetylated tubulin is concentrated near the plasma membrane. Results from .