Every day millions of our cells kill themselves and biologists say, “Thank goodness.” Known as apoptosis, this methodical self-slaughter helps defend against cancer, lets the brain make the right connections during development, and contributes to many other body activities. Newbies can absorb the basics of the process with this pair of tutorials.
Videos of suicidal cells and images such as the “death receptor” add panache to the primer* by postdoc Phil Dash of St. George's Hospital Medical School in London. Embedded in a cell's membrane, the receptor picks up the suicide signal and unleashes enzymes called caspases, which help orchestrate the cell's demise. Learn about the survival pathways that spare cells and read about diseases in which control of apoptosis falters at this site† from graduate student Alasdair Laurie of the University of Leeds, U.K. Too little apoptosis lets tumors run amok, and too much depletes needed cells in Huntington's disease and AIDS.