New research has found that a protein called SAMHD1 plays a crucial role in preventing the SARS-CoV-2 virus from infecting lung cells. The study discovered that when SAMHD1 is removed from lung cells, the virus is unable to enter the cells and replicate. This happens because SAMHD1 helps to suppress the production of a protein called ACE2, which is necessary for the virus to attach to and enter the cells. Without ACE2, the virus is unable to infect the cells, making SAMHD1 a potential target for developing new treatments for COVID-19.