A protein called "Baron", capable of instantly stopping intracellular activity and entering a dormant state, is discovered in bacteria found in Arctic glaciers.

June 16, 2024 9:30:00 p.m.

Animals such as bears and squirrels sometimes engage in a behavior called “hibernation,” in which they almost completely shut down their activity and metabolism during the winter, when food is scarce. A research team led by biologist Sergey Melnikov from Newcastle University has discovered a protein in bacteria found in Arctic glaciers that hibernates and instantly shuts down cellular protein production.

A new family of bacterial ribosome hibernation factors | Nature

https://www.nature.com/articles/s41586-024-07041-8

Most of life on Earth is dormant, having pulled an ’emergency brake’ | Quanta Magazine

https://www.quantamagazine.org/most-life-on-earth-is-dormant-after-pulling-an-emergency-brake-20240605/

For many organisms, hibernation is essential for survival when they face harsh environments such as lack of food or cold, which slow their activity and metabolism. In some animals, even if the entire body does not enter hibernation, a subpopulation of cells in the body enters a dormant state and waits for the optimal time to become active.

Researchers have discovered a number of “hibernation factors,” proteins that help cells induce and maintain a state of dormancy. When cells detect a harmful condition, such as starvation or cold, they produce these hibernation factors and shut down their metabolism.

These hibernation factors work by dismantling certain cellular machinery, suppressing gene expression and stopping ribosomes , the process by which new proteins are built. Previous research has shown that protein production by ribosomes explains more than 50% of the energy consumed by cultivating bacterial cells.

Therefore, these hibernation factors are thought to help conserve the energy needed for survival by inhibiting the activity of ribosomes that attempt to produce new proteins.

Melnikov and his team named the hibernation factor present in the bacteria

They found Psychrobacter urativorans in an Arctic “Baron” glacier and analyzed its genetic sequence, revealing that it is a common protein present in approximately 20% of all cataloged bacterial genomes.

Previous research has shown that all known hibernation factors that inhibit ribosome activity operate passively. In other words, they stop synthesizing new proteins once the ribosome has finished building a protein. However, the newly discovered Baron is present in all ribosomes in the bacteria’s cells and is believed to forcibly stop the ribosome from producing proteins, even in the middle of its work.

“Baron’s ability to shut down ribosomal activity mid-course could be important for microbes under stress,” says Mee-Gan Frances Yap, a microbiologist at Northwestern University. “When bacteria are actively growing, they produce a lot of ribosomes and RNA. But when these bacteria are under stress, they shut down the translation of RNA into new proteins, which will likely save energy during the hibernation period.”

The researchers say that unlike other hibernation factors, the Baron mechanism is a reversible process: affected ribosomes quickly enter a dormant state, but can quickly resume protein production when conditions become favorable for them.

The research team compared proteins from Psychrobacter urativorans and Mycobacterium tuberculosis, a genetically closely related human pathogen, by dipping them in boiling water. Both proteins were revealed to have a Baron-like hibernation factor bound to the A site of the ribosome. On the other hand, Baron was not found in Escherichia coli and Staphylococcus aureus, which are commonly used as models of cellular dormancy. Helena Bueno, from the University of Newcastle, said: ‘We investigated a little-studied corner of the natural world and discovered Baron.’ Luckily.’

“We may be able to use the knowledge gained from Baron to advance research into organisms that can resist climate change,” Melnikov said of the discovery.