The invention provides a method for detecting apoptosis in a cell comprising detecting an alteration in any one of: i) a p55PIK polypeptide having an amino acid sequence as set out in SEQ ID NO:1; ii) a polypeptide having at least 80 % homology with i); iii) a nucleic acid encoding a polypeptide having the sequence set out in i) or ii); iv) a nucleic acid which hybridises under stringent conditions to the sequence set out in iii); or v) the complement of iii) or iv). The invention accordingly provides a method of modulating apoptosis by modulating p55PIK gene expression and a method for identifying genes associated with p55PIK gene expression and thus identifying other genes associated with apoptosis. The invention also provides a novel nucleic acid sequence encoding the promoter region for p55PIK.
