CD95L concatemers highlight difference in the manner CD95-mediated apoptotic and non-apoptotic pathways are triggered

To better understand the stoichiometry of CD95L required to trigger apoptotic and non-apoptotic signals, we generated several CD95L concatemers from dimer to hexamer conjugated via a flexible link (GGGGS)2. These ligands reveal that although the hexameric structure is the best stoichiometry to trigger cell death, a dimer is sufficient to induce the apoptotic response in CD95-sensitive Jurkat cells. Interestingly, only trimeric and hexameric forms can implement a potent Ca2+ response, suggesting that while CD95 aggregation controls the implementation of the apoptotic signal, both aggregation and conformation are required to implement the Ca2+ pathway. ### Competing Interest Statement PL is involved in patents protecting the use of CD95 or CD95L in chronic inflammatory disorders and cancers (WO2014118317; WO2015189236; WO2015158810; WO2015104284; WO2017149012; WO2018130679).