In a report currently appearing in the online issue of the journal Nature Cell Biology, scientists at the University of North Carolina at Chapel Hill School of Medicine and the UNC Lineberger Comprehensive Cancer Center describe - for the first time - how some proteins interact to ensure that the cell does not continually divide when its DNA is damaged.

Although not yet clinically applicable, the study's findings offer new knowledge on how cells rapidly degrade unnecessary and potentially harmful proteins for recycling. They also point to a possible target for drug development: a cellular enzyme family involved in preventing replication of damaged genomic material.

"Inevitably, the molecular pathways controlling many cellular processes such as DNA repair must interact with those regulating cell division," said Dr. Yue Xiong, professor of biochemistry and biophysics at UNC. "An alteration in this critical interaction may be the cause of human cancer, which is characterized by deregulated cell cycle and accumulation of gene mutations."

Xiong, the report's senior author, added that a major goal of his UNC Lineberger laboratory is to understand the molecular mechanisms controlling cell cycle progression - the complex processes by which cells divide and DNA is replicated - and how this control becomes altered during tumor development.

Scientists have learned that the cell's ability to earmark proteins for recycling or degradation, often a target of cancer development, is key to controlling cell division.

Xiong's laboratory has been studying a family of enzymes called E3 ubiquitin ligases. These ligases place a long tail of ubiquitin molecules on proteins, which are then slated for degradation and recycling. The degradation sign
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Contact: Leslie H. Lang
llang@med.unc.edu
919-843-9687
University of North Carolina School of Medicine
8-Oct-2004