The invention provides methods and compositions relating to apoptosis regulating proteins, known as Casper proteins, and related nucleic acids. The proteins may be produced recombinantly from transformed host cells from the disclosed Casper encoding nucleic acid or purified from human cells. The invention provides specific hybridization probes and primers capable of specifically hybridizing with the disclosed Casper gene, Casper-specific binding agents such as specific antibodies, and methods of making and using the subject compositions in diagnosis, therapy and in the biopharmaceutical industry.