A conserved archaeal protein with evolutionary links to bacterial ribosome hibernation and eukaryotic energy sensing.

AHA, a conserved archaeal ribosome-associated protein, links bacterial hibernation factors and eukaryotic energy sensors, revealing an evolutionary connection across domains.

• Why it matters: Understanding archaeal ribosome hibernation fills a significant knowledge gap, as it is less characterized than in bacteria and eukaryotes, impacting insights into stress survival mechanisms.
• What they did: Using cryoEM of archaeal lysates, researchers identified AHA, a two-module protein that binds ribosomes, occludes key functional sites, and shares homology with bacterial HPF and eukaryotic AMPKγ.
• The result: AHA's conserved nature and structural features suggest a universal role in ribosome hibernation and energy sensing, enabling deeper understanding of cellular stress responses and evolutionary biology.