Fig. 6
From: Lipid order and charge protect killer T cells from accidental death
On DOPS, perforin assemblies retain properties found in prepores. a EM images of DOPC and DOPS monolayers after incubation with TMH1-PRF (–DTT), unlocked TMH1-PRF +DTT, or with WT-PRF, at subunit resolution. On DOPC, TMH1-PRF prepores are visible as short, loose assemblies, which grow into arc- and ring-shaped pores after unlocking (TMH1-PRF +DTT) or when using WT-PRF, accompanied by a tighter subunit packing, and fully consistent with previous observations6. On DOPS, initially short assemblies formed by TMH1-PRF appear similar to prepores formed on DOPC. After unlocking with DTT or when incubating with WT-PRF, the clusters retain signatures of short assemblies, and lack the tight packing observed for perforin pores. Scale bar, 50 nm. b Length distributions of assemblies as found in isolated assemblies and clusters on DOPS that show subunit repetitions (see Methods). c Average subunit spacing (± standard deviation) on DOPS; these results are comparable with previously published data on perforin prepore (TMH1-PRF) assemblies formed on PC-rich membranes, with sizes ranging between 2 and 10 subunits and a subunit spacing of 3.86 ± 0.13 nm; on such PC rich membranes, pore assemblies are significantly larger and have a tighter subunit spacing, 2.55 ± 0.09 nm6. Source data for b and c are provided as a Source Data file.
