Radiation-Induced Protein Protects Against Radiation Damage

TCTP is a member of a group of proteins involved in DNA damage response.

The Science

Understanding how cells repair DNA damage from ionizing radiation is a major focus of low-dose radiation biology research. New research now explains how a multifunctional protein protects against low dose radiation-induced DNA damage. The translationally controlled tumor protein (TCTP) is a highly conserved protein found in mammals, plants, and yeast. TCTP participates in numerous cellular processes, including protein synthesis, cell growth, and allergic reactions. A critical role of TCTP is found in a cell’s ability to repair DNA damage and maintain genomic integrity in response to stressful agents. The investigators had previously observed adaptive responses when normal human cells were exposed to low doses of gamma rays that mimic human exposure during diagnostic radiography or occupational activities. Specifically, these irradiated cells exhibited significantly less chromosomal damage than observed in nonirradiated cells. Their new findings show that this protective effect only occurs in the presence of TCTP. This study demonstrates that after exposure to low doses of ionizing radiation, signals are activated that have the potential to stimulate protective mechanisms that could reduce the risk from radiation exposure. The new study was carried out by scientists at the University of Medicine and Dentistry of New Jersey and the Fourth Military Medical University in the People’s Republic of China.


Upon exposure of normal human cells to low-dose γ rays, the TCTP protein level was greatly increased, with a significant enrichment in nuclei. In normal cells, TCTP did not affect such cell-cycle progression toward division under normal, homeostatic conditions. However, TCTP had a prominent effect on stress-induced cell-cycle checkpoints, which ensure that the cell cycle progresses without any DNA damage. Researchers found that TCTP interacted with p53, a critical protein component of such checkpoints that maintains genomic integrity.

Principal Investigator

Edourd I. Azzam
University of Medicine and Dentistry of New Jersey

BER Program Manager

Resham Kulkarni

U.S. Department of Energy, Biological and Environmental Research (SC-33)
Biological Systems Science Division
[email protected]


Zhang, J., S. M. de Toledo, B. N. Pandev, G. Guo, D. Pain, H. Li, and E. I. Azzam. 2012. “Role of the Translationally Controlled Tumor Protein in DNA Damage Sensing and Repair,” Proceedings of the National Academy of Sciences USA 109(16), E926–E933. DOI: 10.1073/pnas.1106300109.