Protein Combination Triggers 9-1-1 To Make Cells Fight Cancer-causing agents

The finding -- published in the journal Cell -- is seen as a breakthrough in cancer research that could lead to better cancer diagnosis through targeting defective genes. It may also pave the way for a drug that activates the SOS response in cells.

"With no exaggeration, this is a result that many in the field have awaited with anticipation for some 20 years," said Michael Ellison, director of the Institute for Biomolecular Design and Project CyberCell at the University of Alberta.

The study demonstrated that a process known as ubiquitination, sometimes called the "kiss of death" for proteins, can serve a completely different function. Xiao and a team of graduate students found that ubiquitination can actually be used to activate the 9-1-1 protein complex, warning cells to stop dividing with damaged DNA that leads to cancer.

"It has been known for many years that 9-1-1 was important, but scientists did not know how it was turned on," said Xiao, department head and professor of microbiology and immunology at the U of S. "We figured out how 9-1-1 is actually activated when cells face carcinogens."

The next step toward developing diagnostic tools and drug treatments is to test whether this model, which used genes from baker's yeast that have counterparts in people, can apply to human cells as well.

Xiao will present his team's findings and future research directions at the Gordon Research Conference on Mutagenesis at Oxford University this summer.

His study was funded by both the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council.