LIFE SCIENCE

Detailed explanation-1: -Granzymes (Gzms), a family of cytotoxic proteases, are key players in cytotoxic T lymphocyte (CTL) elimination of target cells. Gzms are also expressed by other immune cells, such as natural killer cells [1, 2] and mast cells [3], but we mainly focus on CD8 T cell expression of Gzms here.

Detailed explanation-2: -Cytotoxic CD8 T cells carry out their killing function by releasing two types of preformed cytotoxic protein: the granzymes, which seem able to induce apoptosis in any type of target cell, and the pore-forming protein perforin, which punches holes in the target-cell membrane through which the granzymes can enter.

Detailed explanation-3: -Activation of cysteine proteases called caspases plays a major role in the execution of apoptosis. These proteases selectively cleave vital cellular substrates, which results in apoptotic morphology and internucleosomal fragmentation of DNA by selectively activated DNases.

Detailed explanation-4: -Apoptosis is mediated by proteolytic enzymes called caspases, which trigger cell death by cleaving specific proteins in the cytoplasm and nucleus.