Inhibits p53 binding to mitochondria by reducing its affinity for antiapoptotic proteins Bcl-2 and Bcl-XL. Displays no effect on the transactivational or cell cycle checkpoint control function of p53. Potentially increases reprogramming efficiency of human somatic cells to induced pluripotent stem cells (iPSCs) by silencing p53. Reduces cell death induced by γ-radiation in vitro and protects mice from doses of radiation that cause lethal hematopoietic syndrome. Selectively inhibits heat shock protein 70 (HSP70) activity.