Newly identified protein Imi1 affects mitochondrial integrity and glutathione homeostasis in Saccharomyces cerevisiae.

Glutathione homeostasis is crucial for cell functioning. We describe a novel Imi1 protein of Saccharomyces cerevisiae affecting mitochondrial integrity and involved in controlling glutathione level. Imi1 is cytoplasmic and, except for its N-terminal Flo11 domain, has a distinct solenoid structure. A lack of Imi1 leads to mitochondrial lesions comprising aberrant morphology of cristae and multifarious mtDNA rearrangements and impaired respiration. The mitochondrial malfunctioning is coupled to significantly decrease the level of intracellular reduced glutathione without affecting oxidized glutathione, which decreases the reduced/oxidized glutathione ratio. These defects are accompanied by decreased cadmium sensitivity and increased phytochelatin-2 level.