The intracellular dissipation of cytosolic calcium following glucose re‐addition to carbohydrate depleted Saccharomyces cerevisiae

Abstract

Glucose re-addition to carbohydrate starved yeast cells leads to a transient elevation of cytosolic calcium (TECC). Concomitantly, a cytosolic proton extrusion occurs through the activation of the vacuolar H þ -ATPase and the plasma membrane H þ -ATPases. This study addressed the dissipation of the TECC through intracellular compartmentalization and the possible affects of the H þ -ATPases on this process. Both the vacuole and the Golgi-ER apparatus were found to play important roles in distributing calcium to internal stores. Additionally, the inhibition of cytosolic proton extrusion augmented cytosolic calcium responses. A model where pH dependent cytosolic calcium buffering plays an important role in the dissipation of the TECC in Saccharomyces cerevisiae is proposed.

Vacuolar Cation/H+ Antiporters of Saccharomyces cerevisiae*

“…Vcx1p along with Pmc1p (a high affinity Ca 2ϩ ATPase) were shown to play a key role in the vacuolar translocation of Ca 2ϩ after a cytosolic spike induced by various stimuli (55)(56)(57). In addition to regulating calcium homeostasis, in this paper we show that Vcx1p along with Vnx1p play a role in the sequestration of cytosolic K ϩ into the vacuole.…”

Accumulation and Release of Metal Ions by Brewer's Yeast During Successive Fermentations

“…A general trend of uptake of the ions in the beginning of the process can be noted in all fermentations, followed by calcium ion release 48 h after pitching. It was suggested in a previous report by Kellermayer et al 4 that starved cells subjected to carbohydrate re-addition transiently elevate their cytosolic calcium content. Thus, a rise of the biomass calcium directly after pitching into fresh broth can be due to the starvation that the cells undergo at the end of propagation or a previous fermentation.…”

Ca 2+ homeostasis in the budding yeast Saccharomyces cerevisiae : Impact of ER/Golgi Ca 2+ storage

“…As in all eukaryotic cells, yeast cells employ calcium signalling mechanisms to regulate a wide variety of cellular processes including cell-cycle progression, mating, protein processing, responses to hypotonic stress, maintenance of intracellular pH [1][2][3][4][5][6][7][8] and adequate nutritional and metabolic signalling [9][10][11][12]. Moreover, the toolkit of Ca 2+ signalling proteins in yeast and mammalian cells is remarkably similar.…”

“…Re-addition of glucose to carbohydrate starved yeast cells results in a variety of effects including increased turnover of phosphatidyl inositol, activation of the Ras-adenylate cyclase pathway [40], activation of the plasma membrane H + -ATPase [41], intracellular acidification due to glycolysis, which leads to the activation of the vacuolar H + ATPase [9,42,43] and a transient elevation of cytosolic Ca 2+ or TECC response [10,12]. This TECC response has been shown to depend on glucose uptake and phosphorylation [11].…”