RIP kinases initiate programmed necrosis.

Some lethal stimuli can induce either apoptosis or necrosis, depending on the cell type and/or experimental setting. Until recently, the molecular bases of this phenomenon were largely unknown. Now, two members of the receptor-interacting serine-threonine kinase (RIP) family, RIP1 and RIP3, have been demonstrated to control the switch between apoptotic and necrotic cell death. Some mechanistic details, however, remain controversial.