Anhydrobiosis in yeast: role of cortical endoplasmic reticulum protein Ist2 in Saccharomyces cerevisiae cells during dehydration and subsequent rehydration

Two Saccharomyces cerevisiae strains, BY4741 and BY4741-derived strain lacking the IST2 gene (ist2 Delta), were used to characterise the possible role of cortical endoplasmic reticulum (ER) protein Ist2 upon cell dehydration and subsequent rehydration. For the first time, we show that not only protein components of the plasma membrane (PM), but also at least one ER membrane protein (Ist2) play an important role in the maintenance of the viability of yeast cells during dehydration and subsequent rehydration. The low viability of the mutant strain ist2 increment upon dehydration-rehydration stress was related to the lack of Ist2 protein in the ER. We revealed that the PM of ist2 increment strain is not able to completely restore its molecular organisation during reactivation from the state of anhydrobiosis. As the result, the permeability of the PM remains high regardless of the type of reactivation (rapid or gradual rehydration). We conclude that ER protein Ist2 plays an important role in ensuring the stability of molecular organisation and functionality of the PM during dehydration-rehydration stress. These results indicate an important role of ER-PM interactions during cells transition into the state of anhydrobiosis and the subsequent restoration of their physiological activities.

Automated summary

The study showed that both plasma membrane and endoplasmic reticulum protein Ist2 play important roles in maintaining the viability of yeast cells during dehydration and rehydration. The low viability of the ist2 mutant strain during dehydration-rehydration stress was due to the lack of Ist2 protein in the endoplasmic reticulum. Additionally, the mutant strain's plasma membrane was unable to fully restore its molecular organization during reactivation, resulting in high permeability regardless of the type of rehydration.