St. Jude researchers find key step in programmed ...( Investigators at St. Jude Childrens ...),Health

Investigators at St. Jude Childrens Research Hospital have discovered a dance of proteins that protects certain cells from undergoing apoptosis, also known as programmed cell death. Understanding the fine points of apoptosis is important to researchers seeking ways to control this process.

In a series of experiments, St. Jude researchers found that if any one of three molecules is missing, certain cells lose the ability to protect themselves from apoptosis. A report on this work appears in the advance online publication of Nature.

This is probably the first description of what is happening mechanistically that contributes to the ability of cells to delay apoptosis, said James Ihle, Ph.D., the papers senior author and chair of the St. Jude Department of Biochemistry. It provides incredible insights into how three proteins work and how they can control apoptosis.

The molecular interactions that St. Jude researchers describe in Nature play out in nerve cells and blood cells that develop from hematopoietic (blood-forming) stem cells.

A research team elsewhere recently reported that Kostmanns syndrome, a potentially fatal inherited deficiency of granulocytes in children, caused by excessive apoptosis of granulocytes, results from a deficiency in one of the three proteins, called Hax1.

This suggests that the protein is playing basically the same role in humans as we described in mice, Ihle said.

Apoptosis rids the body of faulty or unneeded cells. However, molecular malfunctions that trigger apoptosis may cause some diseases, including Parkinsons disease. Understanding the biochemical interactions that control the extent of programmed cell death could lead to new treatments.

St. Jude biochemists have long studied how cytokinessmall proteins used by neurons and blood-borne cells to communicate messagescontribute to keeping cells alive. For example, they demonstrated earlier that most cytokines control
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