How SARS-CoV-2 stops cells producing protein

The novel coronavirus SARS-CoV-2, cause of the COVID-19 pandemic, has infected millions worldwide, but scientists are still unpacking how infection by SARS-CoV-2 works. Researchers led by Roland Beckmann of Ludwig Maximilian University Munich and Konstantin M. J. Sparrer of Ulm University have now determined how the coronavirus inhibits the synthesis of proteins in infected cells, effectively disarming the body’s innate immune system (Science 2020, DOI: 10.1126/science.abc8665). The team used cryo-EM to image the viral protein Nsp1 in a complex with the human ribosome, the cell’s protein-making factory. The work shows that after Nsp1 binds to the ribosome, one end of the protein inserts into the mRNA entry channel of the ribosome and blocks it, stopping production of immune system proteins. Earlier work had shown that Nsp1 from the virus that causes SARS suppresses protein production, but the mechanism wasn’t clear. Blocking Nsp1 binding without blocking the function of the ribosome could be a good drug target, the researchers say.