Complex interplay among apoptosis factors: RB, p53, E2F, TGF-beta, cell cycle inhibitors and the bcl2 gene family.

Apoptosis is a fundamental cell program as important as growth, differentiation and quiescence. It regulates tissue development, homeostasis and it is a basic defence against cancer. The cell can undertake multiple apoptotic pathways, where different elements are involved. In this report, we would like to stress particularly that the p53/RB pathway and its complex, interplay with the bcl2 gene family, where paramount elements of apoptosis regulation are operating. It is generally believed that bcl2 blocks apoptosis at the level of the activation of ICE-(Interleukin Converting Enzymes)-like proteases [1,2]. The interconnection between apoptosis and cell cycle is very important and complex and we will start the story from this very up-to-date point of view.