Access

Review

Nature Cell Biology 4, E131–E136 (1 May 2002) | doi:10.1038/ncb0502-e131

AP-1 as a regulator of cell life and death

Eitan Shaulian & Michael Karin

The transcription factor AP-1 (activator protein-1) is involved in cellular proliferation, transformation and death. Using mice and cells lacking AP-1 components, the target-genes and molecular mechanisms mediating these processes were recently identified. Interestingly, the growth-promoting activity of c-Jun is mediated by repression of tumour suppressors, as well as upregulation of positive cell cycle regulators. Mostly, c-Jun is a positive regulator of cell proliferation, whereas JunB has the converse effect. The intricate relationships between the different Jun proteins, their activities and the mechanisms that mediate them will be discussed.