RpS3, a DNA repair endonuclease and ribosomal protein, is involved in apoptosis

It is known that mammalian rpS3 functions as a DNA repair Endonuclease and ribosomal protein S3. It was also observed that several ribosomal proteins or DNA repair Enzymes are related to Apoptosis. We report here a third function of rpS3, induction of Apoptosis. The localization of green fluorescent protein (GFP)-rpS3 is changed to the nuclear membrane when lymphocytic cells undergo rpS3-induced Apoptosis. Transient expression of GFP-rpS3 activates Caspase-8/Caspase-3 and sensitizes cytokine-induced Apoptosis. Deletion analysis reveals that the two functions of rpS3, DNA repair and Apoptosis, use independent functional domains.