Abstract: | Glucose, in the absence of additional nutrients, induces programmed cell death in yeast. This phenomenon is independent of yeast metacaspase (Mca1/Yca1) and of calcineurin, requires ROS production and it is concomitant with loss of cellular K+ and vacuolar collapse. K+ is a key nutrient protecting the cells and this effect depends on the Trk1 uptake system and is associated with reduced ROS production. Mutants with decreased activity of plasma membrane H+‐ATPase are more tolerant to glucose‐induced cell death and exhibit less ROS production. A triple mutant ena1‐4 tok1 nha1, devoid of K+ efflux systems, is more tolerant to both glucose‐ and H2O2‐induced cell death. We hypothesize that ROS production, activated by glucose and H+‐ATPase and inhibited by K+ uptake, triggers leakage of K+, a process favoured by K+ efflux systems. Loss of cytosolic K+ probably causes osmotic lysis of vacuoles. The nature of the ROS‐producing system sensitive to K+ and H+ transport is unknown. Copyright © 2010 John Wiley & Sons, Ltd. |