How the sleeping ribosomes awaken?

How the sleeping ribosomes awaken?

In research published in Proceedings of the National Academy of Sciences (PNAS),  has uncovered the way a bacterial ribosome moves from an inactive to an active form, and how that "wake up call" is key to its survival.

Often described as a cell's protein factory, ribosomes translate messenger RNA and link amino acids together to form new proteins. Ribosomes catalyze proteins that are essential for all life.

In bacteria, ribosomes can take an inactive form called hibernating 100S ribosome. Because protein synthesis accounts for more than half of a cell's energy costs, the inactive ribosome form helps bacteria survive under stressful conditions. During limited nutrient access, antibiotic stress, host colonization, adaptation to the dark and biofilm formation, bacteria aim to conserve energy by shutting down the protein factory.

Scientists have observed that the hibernating form of the ribosome is not a permanent state and that if conditions are favorable, it can "wake up" and return to its active form, called 70S, and begin to initiate new cycles of protein synthesis.

Researchers were looking for the protein factor that caused the 100S form to return to the intermediate 30S and 50S forms and subsequently into the active 70S form. Studying Staphylococcus aureus, commonly known as staph, they found that a GTP hydrolase enzyme called HflX is the wake-up call that will re-activate the ribosome.

HflX GTPases are a family of enzymes that are evolutionarily conserved proteins, meaning they also exist in plants, humans and other bacteria. There has been virtually no study of the protein in human cells, it appears in genetic sequencing mapped to cancer patients and those with neurological symptoms, including tic disorder-like syndromes. Scientists do not yet know what this connection means.