GROWTH-FACTORS AS SURVIVAL FACTORS - REGULATION OF APOPTOSIS

Apoptosis is now widely recognized as a common form of cell death and represents a mechanism of cell clearance in many physiological situati ons where deletion of cells is required. Peptide growth factors, initi ally characterised as stimulators of cell proliferation, have now been shown to inhibit death in many cell types. Deprivation of growth fact ors leads to the induction of apoptosis, i.e. condensation of chromati n and degradation in oligonucleosomesized fragments, formation of plas ma and nuclear membrane blebs and cell fragmentation into apoptotic bo dies which can be taken up by neighbouring cells. Here we discuss the mechanism(s) by which growth factors may inhibit apoptosis.