Viral infection affects important cells' stress response

Nov 14, 2007

Viral infection disrupts the normal response of mammalian cells to outside deleterious forces, cleaving and inactivating a protein called G3BP that helps drive the formation of stress granules, which shelter the messenger RNAs that carry the code for protein formation, said researchers from Baylor College of Medicine in Houston.

Only recently have scientists begun to understand the role of stress granules, said Dr. Richard Lloyd, associate professor of molecular virology and microbiology at BCM, and senior author of the report that appears today in the journal Cell Host and Microbe. The stress granules are formed when a cell is subjected to several kinds of stress, such as nutrient deprivation or virus infection.

“When the cell suffers a major insult, it stops expanding. The business of protein synthesis (in which messenger RNA or mRNA’s genetic code gets translated into proteins that carry out cellular activities) is arrested. The messenger RNA goes into storage until conditions improve for the cells,” he said. “Stress granules are a major storage site for the mRNA.”

However, in poliovirus infection (used in the laboratory because it is a prototype for many kinds of viruses), the stress granules are formed early but as the infection continues, the stress granules disperse.

Lloyd and his colleagues found that the poliovirus infection actually cuts or cleaves G3BP, a protein critical in the formation of the stress granules.

“The cells respond to the viral infection, and then virus is shutting that response off,” said Lloyd. In effect, he said, this type of cell response helps prevent the virus from translating its mRNA into virus proteins and killing the cells.

Other viruses may affect other proteins important in this type of stress response, said Lloyd. “Poliovirus has evolved to target G3BP,” he said.

When he and his colleagues mutated G3BP to make it resistant to being cut or cleaved, they found that stress granules could be formed during virus infection and that this inhibited virus growth in the cells.

“With the cleavage resistant form, the cells can continue to make stress granules, and this interferes with virus reproduction” he said.

Source: Baylor College of Medicine

Explore further: Human brain has coping mechanism for dehydration

add to favorites email to friend print save as pdf

Related Stories

Hoverbike drone project for air transport takes off

7 hours ago

What happens when you cross a helicopter with a motorbike? The crew at Malloy Aeronautics has been focused on a viable answer and has launched a crowdfunding campaign to support its Hoverbike project, "The ...

Study indicates large raptors in Africa used for bushmeat

7 hours ago

Bushmeat, the use of native animal species for food or commercial food sale, has been heavily documented to be a significant factor in the decline of many species of primates and other mammals. However, a new study indicates ...

'Shocking' underground water loss in US drought

7 hours ago

A major drought across the western United States has sapped underground water resources, posing a greater threat to the water supply than previously understood, scientists said Thursday.

Recommended for you

Human brain has coping mechanism for dehydration

4 hours ago

(HealthDay)—Although dehydration significantly reduces blood flow to the brain, researchers in England have found that the brain compensates by increasing the amount of oxygen it extracts from the blood. ...

User comments : 0