Scientists Just Figured Out What The Protein Looks Like That Lets HIV Into Our Cells

Image courtesy of the Wu lab, SIMMIn the foreground, CCR5. In the background you can see the entire complex of proteins that work together to let HIV into cells.This protein below, visualized close up for the first time, is the doorway through which most HIV strains use to enter white blood cells.

It's called CCR5 and it inserts itself into the cell membrane, making a hole in it.

Those holes only open up if the protein on the outside has the right structure. HIV just happens to have the right proteins on the outside of its shell to open up this hole and sneak into the cell, where it overtakes the cells' machinery and starts pumping out copies of itself until the cell is overworked and dies.

As the virus kills off more and more of your white blood cells, your immune system gets weaker and weaker and you lose your ability to fight off infections - even those that are normally harmless - eventually succumbing to one of them.

The receptor is one of two that the virus uses to enter cells. The other is CXCR4 - which researchers had previously figured out. The CCR5 receptor is used by more strains of HIV, so understanding will help researchers make better drugs to treat and prevent HIV infection.

Sadly we can't just block these proteins off - they are needed by the cell for normal, everyday functions too.

The study detailing the receptor was published Sept. 12 in the journal Science Express. They analyzed how the receptor interacts with an HIV drug called maraviroc. When the drug binds the protein, it changes its shape, making it unusable.

Their insights will give researchers a better understanding of how the virus changes to escape these drugs.

Image courtesy of the Wu lab, SIMM]

Image courtesy of the Wu labThis image shows CCR5 side-by-side with alternate HIV co-receptor CXCR4. While the two share similar overall architecture, their binding pockets show important differences in shape and charge distribution.