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Jianping Jin, Ph.D.

Published: January 13, 2009 by


assistant professor of biochemistry and molecular biology,
Medical School

Ubiquitin signaling pathway hoped to lead to cancer cure

Jianping Jin, Ph.D.

Jianping Jin, Ph.D.

Our cells are in constant motion – creating proteins when needed and then destroying them when their job is done. While the cell must be selective at destroying proteins that are no longer needed, too many unwanted proteins can be toxic to our bodies.

Ubiquitin is a small protein that helps the cell with this process. It acts like a tag and attaches itself to unwanted proteins to signal their destruction.

“For example, when our skin is exposed to sunshine, our skin cells will respond to ultraviolet (UV) signals and trigger some protein degradation in order to protect our genome stability,” said Jianping Jin, Ph.D.

Jin studies the ubiquitin signaling pathway toward the greater goal of cancer research. Research shows the accumulation of unwanted proteins, while toxic to the human body, has been linked to numerous diseases, such as cancer.

“We study how DNA damage response controls the degradation of Cdt1, a key DNA replication licensing factor, through the ubiquitin signaling pathway,” he said. “We also study the basic mechanism regulating a newly discovered ubiquitin signaling pathway that is initiated by a new gene, called Uba6, which is an essential gene for development.”

Jin combines biochemical and genetic methods to identify new components in the Uba6-dependent ubiquitin signaling pathway.

“We also try to understand how modification of Cdt1 affects its degradation under UV stress through genome-wide loss-of-function screen,” he adds. “We believe Cdt1 degradation under UV stress is controlled by both ubiquitination and phosphorylation. Previously, we identified the ubiquitin ligase to ubiquitinate Cdt1 and triggered the degradation of Cdt1. Now, we have evidence to support multiple kinases and phosphatases involved in the whole process.”

Jin said he hopes his work will lead to the discovery of essential genes that control the Uba6-dependent ubiquitin signaling pathway, while gaining insight into this essential signaling process.

“We are on the way to identify kinases and phosphatases, which regulate the ubiquitination of Cdt1 under DNA damage response, in order to better understand how our cells respond to DNA damage stress, such as UV and other genomic toxins,” he said. “Cancer is a major human disease. I really hope my research can be translated into clinical meaning and help kill cancer in the future.”