4% Paraformaldehyde-fixed L-929 (treated with 20 ng\/ml TNF alpha, 100 nM Smac mimetic, and 20 \u00b5M z-VAD for 8 h) (M) cell; Triton X-100 at r.t. for 20 min; Antibody incubation with (phospho-MLKL (Ser345)) polyclonal Antibody, unconjugated (bs-25448R) 1:100, 90 min at 37\u00b0C; followed by BF488 conjugated Goat Anti-Rabbit IgG antibody (green, bs-60295G-BF488) at 37\u00b0C for 90 min, DAPI (blue, C02-04002) was used to stain the cell nuclei. PBS instead of the primary antibody was used as the blank control.