Tardigrades, or water bears, hold a strange fascination in the public imagination. Despite being microscopic creatures that we never see, we tend to be obsessed with one particular tardigrade characteristic: their ability to survive in harsh environments, often environments where most other living creatures could not. Though many live in perfectly habitable environments, some live in extreme altitudes, from the Himalayan mountains to the depths of the ocean. They do this by transforming themselves into a tun, or a small, dehydrated lump.
https://www.youtube.com/watch?v=eXBkmLzBHZk
But with water being essential to life, how do tardigrades survive dehydration? A team of researchers at the University of Tokyo have uncovered a potential mechanism that allows tardigrades to survive in their dehydrated state: CAHS proteins. Their findings, published in PLoS Biology, could have a range of health and medical applications.
CAHS proteins, or cytoplasmic-abundant heat soluble proteins, are a unique characteristic to tardigrades. Through several experiments, researchers were able to to identify CAHS proteins as the reason tardigrades survive in their dehydrated state so long.
These proteins create a gel that protects cells from mechanical stress which would otherwise kill these cells and subject tardigrades to the unfortunate consequences of dehydration. Essentially, the gel helps prevent the cell from collapsing as it loses water. As tardigrades rehydrate, the gel recedes, allowing cells to support themselves again without causing damage.
Some work has even explored CAHS proteins in both insects and humans, with variable results. Studies of the proteins in insects are challenging because many methods used to stain the proteins for better visualization use water-based solutions, which can obviously complicate the accuracy of results. The research team used a methanol-based solution instead.
The team also noted that the behavior of these proteins persists even outside of tardigrade cells, signaling interest in studying these proteins for other purposes.
Some applications for CASH proteins include preservation of cellular materials for longer periods of time, and potentially even organs for transplantation.
Sources: Eurekalert!; PLoS Biology