Granzyme J (GZMJ)

Granzymes are serine proteases that are released by cytoplasmic granules within cytotoxic T cells and natural killer cells. Their purpose is to induce apoptosis within virus-infected cells, thus destroying them. Cytotoxic T cells and natural killer cells release a protein called perforin, which attacks the target cells. Researchers used to think that perforin creates pores within the cell membranes, through which the granzymes can enter, inducing apoptosis. However, new evidence indicates that a multimeric complex (Granzyme B, perforin, and granulysin) can enter a cell through the mannose 6-phosphate receptor (or another receptor found in tumor cells) and is enclosed in a vesicle (a sac). Not mentioned in reference Perforin then allows GrB to pass through the vesicle surface and into the cell, causing apoptosis by various pathways.