Perforin-2 is a pore-forming effector of endocytic escape in cross-presenting dendritic cells

This study searched for cell-type specific effectors of endocytic escape in dendritic cells and identified a pore-forming protein, perforin-2 (encoded by Mpeg1), as a dedicated effector exclusive to cross-presenting cells. Whole cell proteomics identified differences in the abundance of tryptic and semi-tryptic (cleaved) perforin-2 peptides between control MutuDCs and cells treated with BafA, CpG or with knockout of asparagine endopeptidase (AEP). This revealed how perforin-2 undergoes proteolytic cleavage releasing its pore forming domain into the organellar lumen.