*Scientists have made a surprising discovery about the SARS-CoV-2 virus that causes COVID-19. They found that the virus can use a human protein to enter cells, which could help explain how coronaviruses jump species.*
For years, scientists have been puzzled by how coronaviruses, which usually infect animals, are able to jump to humans and cause disease. The SARS-CoV-2 virus, which causes COVID-19, is just one example of a coronavirus that has made the jump to humans.
One of the key proteins that the SARS-CoV-2 virus uses to enter cells is called the spike protein. The spike protein binds to a receptor on the surface of cells, called ACE2, and then the virus is able to enter the cell and begin to replicate.
Scientists have been studying the ACE2 receptor for years, and they know that it is expressed on a variety of cells in the human body, including cells in the lungs, heart, and kidneys. This means that the SARS-CoV-2 virus has the potential to infect a wide range of cells in the human body, which could explain the variety of symptoms that COVID-19 can cause.
However, scientists have also been puzzled by the fact that the SARS-CoV-2 virus is able to infect humans so efficiently. The ACE2 receptor is not unique to humans, and it is also found in a variety of animals. So why is the SARS-CoV-2 virus so good at infecting humans?
The new discovery provides a possible answer to this question. Scientists found that the SARS-CoV-2 virus can use a human protein called furin to help it enter cells. Furin is a protease that is involved in a variety of cellular processes, including the activation of other proteins.
The scientists found that furin can cleave the spike protein of the SARS-CoV-2 virus, which allows the virus to more easily bind to the ACE2 receptor. This means that furin could be helping the SARS-CoV-2 virus to infect human cells more efficiently.
The discovery that the SARS-CoV-2 virus can use furin to enter cells could help to explain how coronaviruses jump species. If coronaviruses can use furin to infect human cells, then they could potentially jump to humans from a wide variety of animals that also express furin.
This discovery could also lead to new treatments for COVID-19. If scientists can find a way to block furin from cleaving the spike protein of the SARS-CoV-2 virus, then they could potentially prevent the virus from entering human cells and causing infection.
