Specific serine residues of Msn2/4 are responsible for regulation of alcohol fermentation rates and ethanol resistance.

Despite the fact that Saccharomyces cerevisiae has suicide tendencies since its product affects cell function, it is a key player in alcoholic fermentation. The presence of ethanol in the medium affects membrane integrity and fluidity, as well as the rate of ethanol production. The Msn2/4p transcription factors are key regulators in stress response and play a critical role in cell response to ethanol challenge. Protein kinase A (tpk1/2/3) is controlling the activation/inactivation of a multitude of proteins through phosphorylation at specific serine residues. Targets of Protein Kinase A (PKA) are also msn2/4 and phosphorylation of these two transcription factors by PKA resulting in obstruction of their translocation to the nucleus. This work attempts to reveal the significance of specific serine residues of Msn2/4p, as possible targets of PKA, through substitution of these serine residues with alanine.