Liquid-liquid phase separation promotes animal desiccation tolerance

Significance Recent research has shown that intracellular proteinaceous condensates (membraneless organelles [MLOs]) are involved in various processes, ranging from Alzheimer’s disease to RNA processing, and here we demonstrate that this phenomenon governs a mechanism of anhydrobiosis. The protein Afr LEA6 is found in the desiccation-tolerant life stage of the animal extremophile Artemia franciscana, and the protein engages in two distinct molecular mechanisms to confer protection during water loss. Afr LEA6 forms MLOs that may act as protective nodes for desiccation-sensitive proteins, while a cytosolic fraction of the protein promotes structural integrity of cells during anhydrobiosis. These findings significantly advance our understanding of “life without water” and promote transformative advancements in various fields, ranging from cell preservation technology to improvement of crop desiccation tolerance.