Methyl beta-cyclodextrin reduces accumulation of reactive oxygen species and cell death in yeast

Stabilized F-actin structures have been shown to be detrimental to both mammalian and yeast cells. In yeast, stabilization of actin caused by addition of jasplakinolide, by point mutations in the act1 gene, or by deletion of certain genes that regulate F-actin leads to cell death with hallmarks of apoptosis. In particular, there is an elevation in the levels of reactive oxygen species, and we have shown the importance of the Ras/cAMP pathway for this effect. Here we show that in yeast cells deleted for end3, which functions to regulate actin organization during endocytosis, treatment of cells with methyl beta-cyclodextrin reduces levels of reactive oxygen species and inhibits cell death progression. Methyl beta-cyclodextrin is widely used to disrupt lipid rafts that contain cholesterol. The mechanism through which the rescue is achieved was investigated and we demonstrate that methyl beta-cyclodextrin reduces accumulation of Ras2 at the plasma membrane in Deltaend3 cells. We use FRAP and live cell imaging to determine the possible mechanism through which methyl beta-cyclodextrin functions to elicit this effect on Ras2 localization. Finally, we demonstrate that addition of methyl beta-cyclodextrin to wild-type cells can act to protect cells from acute oxidative stress caused by addition of hydrogen peroxide.