The full-length wild-type (FL WT) caspase-6 used in this study was derived from a synthetic, Escherichia coli codon-optimized (His)6 C-terminally tagged caspase-6 gene (Celtek Bioscience) that was ligated into the NdeI/BamHI sites of the pET11a vector. Caspase-6 variants (C163S, Y198A, and C163S/Y198A) as well as the N-terminally (His)6 tagged FL caspase-6 were generated using Phusion site-directed mutagenesis (Thermo Scientific) in the FL WT caspase-6 construct. Fully cleaved and active caspase-6 was also used in the form of a constitutive two chain (CT), which was designed to independently express the large and small subunits of caspase-6 with the prodomain (residues 1–23) and linker (residues 180–193) removed.9 (link)