Mechanisms regulating the transport of acetic acid in Saccharomyces cerevisiae

Abstract

Cells of the yeast Sacchammyces cerevisiae IGC 4072 grown in medium with acetic acid produced a mediated transport system for acetic acid that behaved as an electroneutral proton symport for the anionic form of the acid. The system could transport propionate and formate but not lactate and pyruvate. Uptake of labelled lactic acid was negligible, no mediated transport system activity for this acid being found. The acetate transporter was also found in cells grown in lactic acid or ethanol media, suggesting that the carrier did not require the presence of an external inducer. When cells were grown in lactic acid medium, uptake of labelled acetic acid, a t pH 5.0, was biphasic and consistent with the presence of two distinct transport modes for the acid. One of these components corresponded to the acetatelproton symport, and the higher affinity system corresponded to a more general monocarboxylate carrier that could also transport lactate, pyruvate and propionate. Both systems were subject to repression by glucose, fructose, sucrose, maltose or galactose. In glucose-repressed cells, the undissociated form of the acids appeared to be the only one that could cross the plasma membrane, a diffusion mechanism being involved in the acid uptake. Under these growth conditions and when the extracellular pH was lower than that of the cytosol, accumulation of the acid could also be observed, it being a function of the ApH.

Alcoholic fermentation of carbon sources in biomass hydrolysates by Saccharomyces cerevisiae: current status

“…In addition, intracellular accumulation of the anion, either by itself or in combination with intracellular acidification, can lead to toxic effects (Casal et al 1996;Eklund 1983;Pampulha and Loureiro-Dias 1990;Russell 1992). Benzoate, for instance, has been implicated in inhibition of autophagy (Hazan et al 2004) and acetate has been demonstrated to induce apoptosis (Ludovico et al 2001).…”

Glucose-induced Ubiquitylation and Endocytosis of the Yeast Jen1 Transporter

“…Jen1 is a lactate-pyruvate-acetate-propionate transporter induced in lactic or pyruvic acid-grown cells (18). Ady2, which accepts acetate, propionate, or formate, is present in cells grown in non-fermentable carbon sources (19). Jen1 has unique regulatory characteristics and has been extensively studied.…”

Characterization, localization and functional analysis of Gpr1p, a protein affecting sensitivity to acetic acid in the yeast Yarrowia lipolytica

“…The toxicity of weak acids is dependent on the pH of the environment. At low pH weak acids are mainly present in the undissociated form and will enter the cell by passive diffusion (Sikkema et al, 1995;van der Rest et al, 1995;Casal et al, 1996;Geros et al, 2000). Inside the cell the acids dissociate due to the more neutral pH and release protons, leading to a decrease of intracellular pH which interferes with several metabolic pathways (Krebs et al, 1983).…”