Hidden alarm system in the cell discovered through the ZAK Molecule

     Scientists at Ludwig-Maximilians-Universität München have discovered that ribosomes, best known for their part in creating proteins, also act as a built-in alarm system that monitors cellular health. When normal protein production is interrupted by stressors like damaged messenger RNA, nutrient shortages, or viral infection, ribosomes can stall and collide with one another. These collisions are not a coincidence. Instead, they serve as a danger signal that activates a protective pathway inside the cell known as the ribotoxic stress response.

    Researchers were able to find that a key protein called ZAK senses these ribosome collisions. When ZAK binds to the stalled ribosomes, it becomes activated and triggers a chain of molecular signals that helps the cell respond to the stress. Depending on how severe the damage is, the cell might attempt to repair itself, slow down protein production, or initiate programmed cell death to prevent further harm. Using advanced imaging techniques like cryo-electron microscopy, the team was able to analyze how ZAK interacts with collided ribosomes at the molecular level.

                                  Ribosome collisions act as an early danger sign within cells an trigger a response.

       This discovery alters the way scientists understand ribosomes, revealing that they are not just protein factories but also significant sensors of cellular stress. Through showing how cells detect internal damage so quickly, the study provides new insight into how stress responses, inflammation, and disease development may be regulated. These findings could eventually contribute to new therapeutic strategies for conditions linked to chronic cellular stress or abnormal protein production.

https://www.cell.com/molecular-cell/fulltext/S1097-2765(20)30189-1 

The Genetics of Fragile X Syndrome

This article discusses one of the most common forms of inherited mental disabilities in humans, Fragile X Syndrome. This syndrome is an X-linked trait, so generally males and females who inherit two genes for this trait are affected more than female carriers are. The severity of symptoms can vary in anyone who has this abnormality. The severity is dependent on how many codon repeats are found on the FMR1 gene on the X chromosome.

Fragile X Syndrome causes affected individuals to not make enough of a protein called fragile x mental retardation protein. This protein attaches to ribosomes between the 30s and 50s subunits to regulate protein synthesis. Before this research, done at UC San Diego, scientists only knew that a deficiency of this protein resulted in proteins that regulate brain functions being synthesized incorrectly. The fact the the protein binds between the 30s and 50s subunits of the ribosome is important, as new proteins are synthesized by passing mRNA through the two subunits. These proteins are imperative to normal cognitive function in humans-and fruit flies. Researchers used fruit flies in the laboratory to map where the protein binds to the ribosomes. This information will hopefully provide the tools necessary in the future to create new treatments for this affliction and help restore at least some cognitive function in those who have lost it.

Secondary article

Ribosmoal Protein Causing New Borne Disease Discovered

And article on Science Daily referencing a journal published in sciencemag explains how the protein causing isolated congenital asplenia (ICA) causes this disorder.  This condition is very rare and has be officially documented in less than 100 cases in medical literature.  These scientists sequenced 23 exomes (the part of the genome formed by exons that get transformed into proteins).  After proper testing and filtering, researchers narrowed down to 4,200 possible genes.   Next, researchers hypothesized which exomes would be more likely to house these gene therefore, deciding to focus on ICA exomes.  The gene RPSA responsible for coding for a protein found in the cell’s protein-synthesizing ribosome was found to be the culprit.  Every individual with a coding mutation in this gene is developed with out a spleen.  These results are puzzling because this ribosome is present in every organ in the body but only seems to effect the spleen. 

                This discovery may make it possible to develop new diagnostic test for ICA and lead to more research on this specific protein-making machinery.