Research in Dr. Nilgun Tumer's Lab:

The major focus of Dr. Nilgun Tumer's laboratory is the mechanism by which ribosome inactivating proteins (RIPs) inhibit cellular translation, viral infection and cause cell death. Dr. Tumer's research is funded by NSF, NIH, and USDA.

Antiviral Activity of Ribosomal Inactivating Proteins

Using random mutagenesis, we isolated nontoxic mutants of pokeweed antiviral protein (PAP) and showed that antiviral activity of PAP can be separated from its cytotoxicity. The alterations in the nontoxic mutants allow PAP to accommodate a narrower range of substrates, thus reducing its activity on ribosomes, while maintaining its antiviral activity.

Endoplasmic Reticulum Stress and Ribosome Interactions

Ricin toxin is feared as a bioterror agent because it can be easily purified from the waste of castor oil production and there are no known antidotes. We discovered that ricin kills cells by a previously unrecognized activity that appears to work in concert with its ability to inhibit protein synthesis. Ricin inhibits a cell defense mechanism known as unfolded protein response or UPR. The UPR causes proteins that fold incorrectly in the endoplasmic reticulum (ER), to be degraded and removed from the ER. After ricin enters a cell, it is transported to the ER and signals the ER to shut down UPR, the cell’s stress response needed for survival. Shiga-like toxins secreted by E. coli, including those blamed for high-profile food poisoning cases recently involving spinach, lettuce and fast-food hamburgers, appear to have a similar mechanism to ricin.

Resistance to Fusarium mycotoxins

The contamination of wheat, barley, and maize with the trico-thecene mycotoxin, deoxynivalenol (DON), due to infection with Fusarium is a worldwide problem. We have carried out a genome wide screen and identified genes targeted by trichothecene mycotoxins.

Developing Antidotes Against Ribosome Inactivating Proteins

We have made exciting discoveries toward the development of antidotes for deadly Ricin and Shiga-like toxins and identified inhibitors that prevent cell death caused by these toxins.

More Info

• Nilgun Tumer's Lab Website