What is the major issue addressed by this paper? The radiation-induced bystander effect (RIBE) is a conserved phenomenon RIBE is an important factor for radiosafety, radiation protection and radiotherapy RIBE can inhibit programmed cell death and promote cell proliferation What is RIBE factor? Worm p53 homologue is critical for RIBE

Cathepsin B was identified as a RIBE factor through genetic screens through educational guess through partial biochemical purification followed by mass spectrometry analysis and RNAi verification through RNAi screen Biochemical purification

Cathepsin B exerts RIBE on unexposed cells through the ced-3 cell death protease insulin-like receptor DAF-2 known DAF-2 signaling pathway the p53 homologue CEP-1 All of the above

The RIBE induced by cathepsin B is CEP-1-dependent Cathepsin B protease activity-dependent daf-2-dependent dependent on the secreted form of cathepsin B All of the above

Cathepsin B can be secreted to the extracellular space is a cysteine protease can mediate long-range signaling can promote cell proliferation All of the above

What are the most important questions that have not been addressed by this paper? Substrates of cathepsin B The downstream signaling pathway of cathepsin B How cathepsin B inhibits cell death How cathepsin B promotes cell proliferation How cathepsin B causes stress response