The story of how mitochondria are recruited during times of stress to choreograph apoptosis--the cell's dance of death--is a story that fails to tell which particular set of steps the cells use most often, according to investigators at St. Jude Children's Research Hospital and the La Jolla Institute of Allergy and Immunology (San Diego, CA).
Mitochondria are sacs of enzymes in the cell that extract energy from food and store this energy in the high-powered chemical bonds of molecules called ATP. Virtually all activity of cells requires energy supplied by ATP, which acts as the "currency" with which the cell "buys" chemical reactions.
The fact that more than 100,000 research papers on apoptosis have been published is ironic, since this vast amount of information contributes to the confusion over which signaling pathways are most important for triggering this process, according to Douglas R. Green, Ph.D., chair of Immunology at St. Jude and holder of the Peter C. Doherty Endowed Chair of Immunology. Green is senior author of an editorial on apoptosis that appears in the current issue of Science.
Apoptosis is the orderly process that both sculpts developing organisms out of a mass of replicating cells and disposes of irreparably damaged, mutated or infected cells. For example, cells that suffer DNA mutations that cannot be repaired undergo apoptosis to prevent them from forming a tumor.