Bim plays apoptosis offense

A revision of competing ideas about programmed cell death is in order, according to results from Weber et al. (page 625). The work gets a step closer to nailing down the controversial role of the BH3-only family of proteins as playing offense on the pro-death team of apoptotic proteins, rather than defense against the opposing protective agents.

Three groups of apoptosis proteins control a cell's life-or-death fate: Bax/Bak (the executioners) and BH3-only proteins are pro-apoptotic, whereas a subset of Bcl-2 proteins are anti-apopototic. But researchers have had a hard time deciding how the BH3-only proteins, a group that includes Bim, factor into the equation. One side argues that BH3-only proteins bind to Bax/Bak directly to turn on these killing machines. Another line of...