A protein called 'Baron' that can instantly stop intracellular activity and enter a dormant state is discovered in bacteria found in Arctic glaciers
Animals such as bears and squirrels sometimes engage in a behavior called 'hibernation,' in which they almost completely stop their activity and metabolism during the winter when food is scarce. A research team led by biologist Sergey Melnikov of Newcastle University has discovered a protein in bacteria found in Arctic glaciers that hibernates and instantly stops cellular protein production.
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For many organisms, hibernation is essential to survival when they face harsh environments such as food shortages or cold, slowing down 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 dormant state. 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 shutting down ribosomes , the process by which new proteins are built. Previous research has shown that protein production by ribosomes accounts for more than 50% of the energy used by growing bacterial cells.
Therefore, it is believed that these hibernation factors work to conserve the energy needed for survival by inhibiting the activity of ribosomes that try to produce new proteins.
Melnikov and his team named the hibernation factor 'Baron' from the bacterium
Previous research has shown that all known hibernation factors that inhibit ribosome activity function passively. In other words, they stop the synthesis of new proteins after ribosomes have finished constructing proteins. However, the newly discovered Baron is present in all ribosomes in the cells of the bacteria in question, and is thought to forcibly stop ribosomes from producing proteins even in the middle of their work.
'Baron's ability to stop ribosomal activity midstream could be important for microbes under stress,' says Mee-Gan Frances Yap, a microbiologist at Northwestern University. 'When bacteria are actively growing, they're producing lots of ribosomes and RNA. But when these bacteria are under stress, they shut down the translation of RNA into new proteins, likely to conserve energy for the hibernation period.'
The researchers say that unlike other hibernation factors, Baron's mechanism is a reversible process: affected ribosomes rapidly 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 the genetically closely related human pathogen Mycobacterium tuberculosis by submerging them in boiling water. It was revealed that both proteins have a hibernation factor similar to Baron 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 cell dormancy, so Helena Bueno of Newcastle University said, 'We looked into a little-studied corner of the natural world and discovered Baron by chance.'
'We may be able to use the knowledge we gain from Baron to advance research into organisms that can withstand climate change,' Melnikov said of the discovery.
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