Dynamic aspects of vacuolar and cytosolic amino acid pools of Saccharomyces cerevisiae

Abstract

By using the Cu2+ method (Y. Ohsumi, K. Kitamoto, and Y. Anraku, J. Bacteriol. 170:2676-2682, 1988) for differential extraction of the vacuolar and cytosolic amino acid pools from yeast cells, the amino acid compositions of the two pools extracted from Saccharomyces cerevisiae cells, grown in synthetic medium supplemented with various amino acids, were determined. Histidine and lysine in the medium expanded the vacuolar pool extremely. Glutamate also accumulated in the cells, but mainly in the cytosol. The composition of amino acids in the cytosolic pool was fairly constant, in contrast to that in the vacuolar pool. Cells grown in synthetic medium supplemented with 10 mM arginine accumulated arginine in the vacuoles at a concentration of about 430 mM. This large arginine pool was metabolically active and was effectively utilized during nitrogen starvation. Arginine efflux from the vacuoles was coupled with K+ influx, with an arginine/K+ exchange ratio of 1, as judged by the initial rate. The vacuolar arginine pool was exchangeable with lysine added to the medium and was decreased by treatment of the cells with the mating pheromone, alpha-factor.

Patch Clamp Studies on V-type ATPase of Vacuolar Membrane of Haploid Saccharomyces cerevisiae

“…With the Goldman equation and using the reversal potentials of these anions, permeability ratios were calculated to be 2.8 Ϯ 0.2: 1:0.5 Ϯ 0.3:0.1 Ϯ 0.015 for NO 3 Ϫ :Cl Ϫ :F Ϫ :glutamate Ϫ . These results are consistent with previous reports that indicate that there is an electrogenic anion transporter on the vacuole membrane (30), and that glutamate is accumulated mainly in the cytoplasm (31) and nitrate in the vacuole (32).…”

Regulation of Amino Acid, Nucleotide, and Phosphate Metabolism in Saccharomyces cerevisiae

“…The vacuole is an organelle with a well-established role in amino acid homeostasis (Matile and Wiemken 1967;Cooper 1982a;Kitamoto et al 1988;Klionsky et al 1990;JacqueminFaure et al 1994;Sekito et al 2008). The vacuolar transport systems are listed in Table 6 (Sekito et al 2008).…”

“…If available, arginine is transported into cells by the arginine permease Can1 (Hoffmann 1985), after which it is transported into the vacuole by the Vba2 transporter (Ohsumi and Anraku 1981;Sato et al 1984;Shimazu et al 2005). Greater than 90% of free arginine within cells, i.e., arginine not incorporated in protein, is compartmentalized within the vacuole (Messenguy et al 1980;Kitamoto et al 1988;Ohsumi et al 1988). The mechanisms enabling cells to properly coordinate and regulate levels of arginine in cytoplasmic pools are not well understood.…”

Amino Acids: Sensing and Implication into Aging

“…The yeast vacuole, an organelle similar to the mammalian lysosome, accumulates nutrients including amino acids (Kitamoto et al, 1988), and mTORC1 recruitment is conserved in yeast [5]. In addition, high intraluminal concentrations of certain amino acids have also been shown in lysosomes [18].…”