ИСТИНА

In exponentially growing yeast cells mitochondria form a net-like structures. However, in stationary phase and under stressful conditions the frequencies of mitochondrial fissions is higher than the frequencies of the fusion events. As a result, multiple separated mitochondria or separated mitoplasts surrounded by single outer membrane could be detected in the cells [1]. We have found that after heat shock or in the presence of high concentration of ethanol two distinct populations of mitochondria appear in individual cells: one population with high and another one with low transmembrane potential. Similar results were obtained in stationary phase cells or cells treated with 'fusel' alcohols. The latter mimics the nitrogen starvation in yeast and induces pseudohyphal growth [2]. We found that the presence of both mitochondrial populations are required for butanol-induced formation of the pseudohyphae [3]. Indeed, dissipation of transmembrane potential by uncoupler FCCP prevented of pseudohyphae formation. At the same time, the knockouts of retrograde pathway gene, RTG1, RTG2 or RTG3, were also effective in prevention of butanol-induced pseudohyphal growth. Importantly, retrograde pathway is thought to be induced by depolarized mitochondria. We suggest that the interplay of these two signaling pathways results in a specific cellular response to the environmental stimuli.