Two-dimensional gel electrophoresis and FTIR spectroscopy reveal both forms of yeast plasma membrane H(+)-ATPase in activated and basal-level enzyme preparations

Critical findings on the activation cascade of yeast plasma membrane H+-ATPase

Strains of the yeast Saccharomyces cerevisiae, deficient in either of its two G-proteins, in the Snf3 and Rgt2 sensors, in the Gpr1 receptor and in various hexokinases were tested for their ability to start the activation cascade with a metabolizable monosaccharide that leads eventually to activation of plasma membrane H(+)-ATPase. The acidification rate after addition of glucose to glucose-grown cells and of galactose to galactose-grown ones, and the rate of ATP hydrolysis by purified plasma membranes in both types of cells were studied. It appears unequivocally that phosphorylation of the monosaccharide is essential for the activation; the role of the Gpa2 protein (possibly in combination with the Gpr1 receptor) is very probable while the two sensors appear to play somewhat ambiguous roles - in the absence of both the activation was actually higher than in the parent strain. The Gpa1 G-protein is not involved in acidification but may function in ATPase activity where, in addition to the phosphorylation step, other factors can play a role. There appear to be alternative pathways leading to the ultimate activation of the H(+)-ATPase, not necessarily involving G-proteins.

Current awareness on yeast

In order to keep subscribers up-to-date with the latest developments in their field, this current awareness service is provided by John Wiley & Sons and contains newly-published material on yeasts. Each bibliography is divided into 10 sections. 1 Books, Reviews & Symposia; 2 General; 3 Biochemistry; 4 Biotechnology; 5 Cell Biology; 6 Gene Expression; 7 Genetics; 8 Physiology; 9 Medical Mycology; 10 Recombinant DNA Technology. Within each section, articles are listed in alphabetical order with respect to author. If, in the preceding period, no publications are located relevant to any one of these headings, that section will be omitted. (3 weeks journals - search completed 5th. Dec. 2001)