This is a good study showing how a particular protein (TCTP) is up-regulated following radiation exposure. A significant role of the protein is to prevent cell death, so it's no surprise that it's summoned after the exposure. Once up-regulated, it helps to prevent further DNA damage, a general phenomenon known as adaptive response.
One of the problems of all cellular-response-to-radiation studies, is that we don't know how to interpret the interplay among the many, various responses. Any particular study examines one unique aspect, but there are many studies and many aspects. And we don't know how many cellular response pathways are yet to be identified.
See my page "LNT Model & Radiation Studies" in the upper right, for a broader perspective.