DAP-5 is involved in MycN/IFNgamma-induced apoptosis in human neuroblastoma cells.

Death associated protein-5 (DAP-5) is a ubiquitously expressed member of the translation initiation factor eIF4G family that lacks the eIF4E binding site. A dominant negative fragment of DAP-5 protects HeLa cells from IFNgamma-induced cell death. By employing a functional approach we examined the role of DAP-5 in human neuroblastoma cells that are sensitized for IFNgamma-induced apoptosis by tetracycline controlled MYCN expression. DAP-5 fragment transcribed at high levels and translated into a functional miniprotein of 28 kDa protected neuroblastoma cells from IFNgamma-induced apoptosis. Reduced serum levels were toxic to cells constitutively expressing DAP-5 fragment suggesting that DAP-5 protein is essential for both viability and death of human neuroblastoma cells.