March 9, 2007

Lecturer delves into cell communication

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The Salk Institute’s Tony Hunter, Ph.D., center, with Vanderbilt’s Kathleen Gould, Ph.D., and Steven Hanks, Ph.D., after last week’s Discovery Lecture. (photo by Mary Donaldson)

Lecturer delves into cell communication

In 1979, Tony Hunter, Ph.D., discovered a major clue to the way cells grow and communicate with each other — a chemical “on-off” switch that can lead to cancer.

Discovery of this important signaling mechanism — called tyrosine phosphorylation — ultimately led to the development of the drugs Gleevec, Iressa and Tarceva.

Today, Hunter and his colleagues at the Salk Institute for Biological Studies in La Jolla, Calif., are mapping out other pathways that may one day be useful in predicting the likelihood that breast cancer cells, for example, will spread to other parts of the body.

“We might be able to develop biomarkers so that you could … see (in a biopsy) whether markers that could predict motility (of tumor cells) are highly present,” Hunter said. The other hope is that new therapies will emerge from the research, although “that's a long way down the line,” he said.

Last Thursday, Hunter, professor of Molecular & Cell Biology at the Salk Institute, delivered the 10th in a series of Discovery Lectures sponsored by Vanderbilt University Medical Center.

In introducing his topic, “Signal transduction in disease and the response to DNA damage,” the Cambridge University-trained biochemist described the remarkable and confounding complexity of signaling pathways involved in normal and abnormal growth.

Many of these pathways involve protein kinases, enzymes that “phosphorylate,” or attach phosphate groups to the amino acids, including tyrosine, that make up proteins. Other enzymes, called phosphatases, can remove the phosphate groups.

Proteins also can be reversibly modified by the attachment of sugars, lipids and other proteins. These events, called reversible post-translational modifications, dynamically regulate the activity of proteins involved in cell growth, differentiation, migration, DNA repair and other essential functions.

Hunter has become internationally known for his ability to characterize these modifications at the molecular level. His work has led to greater understanding of the series of mutations that, by affecting the activity of various proteins and pathways, can lead to cancerous growth.

For a complete schedule of the Discovery Lecture Series and archived video of previous lectures, go to