Apoptosis, or programmed cell death, normally eliminates cells that are no longer needed or that threaten the organism. But too little apoptosis can lead to cancer and autoimmune diseases, while excessive apoptosis can lead heart failure, stroke and neurodegeneration. In a study published in the July 14 issue of Molecular Cell, Evripidis Gavathiotis, Ph.D., and colleagues describe an unexpected new shape for the key pro-apoptotic protein known as BAX. BAX had been thought to exist in just one molecular conformation. These new findings suggest a dual regulatory role for BAX: depending on the situation in the cell, BAX assumes one shape that promotes cell death and another that resists cell death. Ongoing studies will investigate whether this newly discovered BAX conformation is linked to cancer cell resistance to chemotherapy. Changing BAX’s shape could lead to new therapeutic approaches to treating cancer and other diseases. Dr. Gavathiotis is associate professor of biochemistry and of medicine.