Within the last two to three years there has been an immense focus in the field of science, COVID-19. This pandemic has sparked a myriad of research opportunities as well as brought up questions we didn’t even know we needed answered.

With this, recent research at the University of Sydney shows that our lungs contain a protein that blocks the COVID-19 infection and works to create a protective barrier within our body. The way it works is that a protein receptor found in our lungs sticks to the virus, and then pulls it away from the targeted cells. The protein is known as the Leucine-Rich Repeat-Containing Protein 15 or in short, LRRC15. For context, leucine is an essential amino acid for protein synthesis as well as many other biological functions. The protein is a built-in receptor inside of our bodies that binds to the COVID-19 virus and doesn’t pass on the infection.

Lungs diagram detailed

Initially, the research was published on February 9, 2023, in the PLOS Biology Journal. Led by Professor Greg Neely and his team members, the findings serve to open a new sect of immunology and COVID research, specifically around the protein, LRRC15. Moreover, it creates a path to develop new drugs and treatments to prevent infections such as COVID-19. Greely states that ” This new receptor acts by binding to the virus and sequestering it which reduces infection,” essentially the receptor is able to attach to the virus and “squish” it before it moves to infection. He also pushes the idea that the new receptor can be used to “design broad-acting drugs that can block viral infection or even suppress lung fibrosis.” Continually Dr. Lipin Loo, one of Greely’s team members, mentions, “We think it acts a bit like Velcro, molecular Velcro, in that it sticks to the spike of the virus and then pulls it away from the target cell types,” here he outlines the stickiness of both the receptor and the virus as well as the receptor’s nature to latch onto the virus and “hold” it. In addition, Loo states, “When we stain the lungs of healthy tissue, we don’t see much of LRRC15, but then in COVID-19 lungs, we see much more of the protein,” here he fronts the idea that COVID-19 lungs are far richer in the LRRC15 protein than normal lungs, this may be due to a result of the protein’s ability to immobilize the virus.

To outline COVID-19 infects us by using a spike protein to attach to a specific receptor in our cells. It mainly uses the ACE2 receptor to enter human cells. Moreover, our lung cells have high levels of ACE2 receptors, which is why being infected can often cause severe problems in our lungs. Similar to ACE2, LRRC15 is a receptor for COVID. But, LRRC15 does not support infection, instead, it sticks to the virus and immobilizes it. This prevents other cells from becoming infected. LRRC15 attaches to the spike of the virus and pulls it away from certain target cell types. The LRRC15 protein is widely present throughout our body, it is in the: lungs, skin, tongue, fibroblasts, placenta, and lymph nodes. However, the researchers observe that the lungs “light up” with LRRC15 after infection. They think the new protein is a part of our body’s natural response to combatting the COVID-19 infection. It creates a barrier that separates the virus from our lung cells most susceptible to COVID-19 infection

SARS-COV-2

To connect to our AP Bio Class, we learned about adaptive immunity where we develop an acquired immunity after being exposed to pathogens, a specific response. I see some similarity here in that the LRRC15 protein is specific to immobilizing the COVID-19 infection. Additionally, in our Cell Signalling Chapter, we focused on signal transduction and its stages, reception, transduction, and response. Specifically in the reception stage, we focused on intracellular and transmembrane receptors. I think that LRRC15 would be transmembrane in order for it to efficiently bind to the COVID-19 Spike. With this, however, I would like to see more about the transduction component of the LRRC15 receptor. Lastly in our Enzyme Unit, we learned about how different factors can affect enzymatic activity; heat, pH, and even general surroundings. I wonder which factors work to hinder and work to stimulate the purpose of the LRRC15. I invite any and all comments with additional info relevant to the topics discussed.

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