1. 0 10 20 30 40 50 60 70 80 90 100 013 5 SA-β-Gal positivity (%) Days after 6 Gy of IR exposure 3 Morphology SA-  -Gal 015 Supplementary Fig. S1 A B

2. Supplementary Fig. S2 5 6 11 7 8 9 10 20 22 18 17 12 16 23 21 19 13 15 14 24 Sene 3 1 2 4 pI310 pI310 M.W. (kDa) 70− 50− 30− 20− 10− 100− 200− 5 6 11 7 8 9 10 20 22 18 17 12 16 23 21 19 13 15 14 24 3 1 2 4 Prol

3. Supplementary Fig. S3 ProlSene Serum-free media ProlSene Complete media Dead cells (%) Serum-free media Complete media Actin c-PARP p21 ProlSeneProlSene PC Serum-free media Complete media A BC

4. 050100500(ng/ml) hRKIP Inactivated hRKIP Supplementary Fig. S4