The tie that binds these three seemingly disparate medical conditions is a biochemical chain of events that govern cell size. At the end of this chain, a known drug may work to replace missing or broken parts of the biochemical chain.

"We were doing basic cell biology, investigating how cell growth is coordinated with the cell's energy level," said Kun-Liang Guan, research professor at the University of Michigan Life Sciences Institute. "We found this story that connects all these things together in a logical manner."

Guan, who is also a professor of biological chemistry and a MacArthur Foundation fellow, and postdoctoral fellow Ken Inoki have been investigating the general question of how cell growth is regulated because it can be a factor in cancerous cell growth.

In a study published in the Nov. 26 edition of Cell, the researchers describe how a cell growth regulator gene called TSC2 responds to different levels of available energy, such as the sugar glucose. As expected, they found that TSC2 activity is stepped up in response to energy starvation, which means the cell's growth rate is being slowed to accommodate the less favorable growing conditions.

TSC1 and TSC2 take their name from a kind of tumor. Tuberous sclerosis is a genetic disease in which benign tumors may grow in the brain and nervous system throughout a person's life. Its severity can range from learning disabilities and epilepsy to severe mental retardation and uncontrollable seizures. There is no cure for tuberous sclerosis, but symptoms may be treated with medications to control seizures and behavior problems.

The genes TSC1 and TSC2 make two proteins that bind together to form a complex which helps control a cell's growth and its final size. A d
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Contact: Karl Leif Bates
batesk@umich.edu
734-647-1842
University of Michigan
26-Nov-2003