Researchers discover how Ebola enters human cells

Researchers recently discovered how the Ebola virus smashes into the cytoplasm of human cells, which could identify a target for blocking the infection process of the potential bioterrorism agent.

Lukas Tamm, a researcher from the University of Virginia School of Medicine, and his team examined what happens after the Ebola virus is engulfed by human cells and contained within a vesicle. Tamm's team discovered that the pH level inside the vesicle triggers the surface glycoprotein on the virus to form a sort of fist that allows the virus to punch into the cell's cytoplasm.

Once the Ebola virus enters the cytoplasm, it can turn the cell into a virus production factory.

"If it stayed in the vesicle, it would be not much of a problem," Tamm said. "The cell could digest it. But then it escapes from that internal vesicle into the body of cell, and that's when the danger happens. It does that by fusing its own membrane with that cellular vesicle membrane, and that lets the RNA of the virus out into the cell to replicate, to basically cause havoc in those cells."

Tamm said that when the Ebola virus approaches a cell, the glycoprotein that becomes the fist looks more like an outstretched hand. The researchers examined the amino acids within the virus that are necessary for the hand to become a fist.

"If you lose those, it would always be in the extended hand formation," Tamm said.

Tamm's team worked with other University of Virginia researchers to test the theory on harmless virus-like particles that act like Ebola. The researchers found that Tamm's hypotheses about the fist-clenching process held true in test tubes and live cells.

The study could bring researchers closer to stopping Ebola and other viruses with similar structures.

"Once you have visualized the molecular shape changes that these structures undergo upon cell entry, you can see what molecules or potential anti-viral drugs could interfere with this process," Tamm said. "You have these contacts that need to be made to make the clenching of the fist happen - if you could find a molecule that throws a wrench into the gears of that mechanism, you could actually block that from happening."

Tamm's team recently published the study in the Journal of Virology.