Possible roles of CAHS proteins from Tardigrade in osmotic stress tolerance in mammalian cells.

Anhydrobiosis, a phenomenon in which organisms survive extreme dehydration by entering a reversible ametabolic state, is a remarkable example of survival strategies. This study focuses on anhydrobiosis in tardigrades, which are known for their resilience to severe environmental conditions. Tardigrades utilize several protective mechanisms against desiccation, notably the constitutive expression of cytoplasmic abundant heat soluble (CAHS) proteins in Ramazzottius varieornatus. These proteins share similarities in their amphiphatic alpha helices with late embryogenesis abundant (LEA) proteins, but differ significantly in their amino acid sequences. In this study, we further explored the functionality of CAHS proteins by analyzing their role in aggregation and tolerance to hyperosmotic stress in mammalian cells. Using live cell imaging, we examined the subcellular localization of several CAHS and LEA proteins in response to hyperosmotic stress. The expression of CAHS1, CAHS3, and CAHS8 tended to enhance the resilience to the hyperosmotic conditions. These findings not only deepen our understanding of the molecular mechanisms of anhydrobiosis but also highlight the potential of CAHS proteins as cryoprotectants.Key words: anhydrobiosis, Tardigrades, live imaging, disordered proteins, desiccation tolerance.