This family consists of apoptosis inhibitory protein 5 (API5) sequences from several organisms. Apoptosis or programmed cell death is a physiological form of cell death that occurs in embryonic development and organ formation. It is characterised by biochemical and morphological changes such as DNA fragmentation and cell volume shrinkage. API5 is an anti apoptosis gene located in <taxon tax_id="9606">Homo sapiens</taxon> chromosome 11, whose expression prevents the programmed cell death that occurs upon the deprivation of growth factors [<cite idref="PUB00011539"/>,<cite idref="PUB00011538"/>].