Perforin Granzyme Apoptosis Pathway

1. Perforin Granzyme Apoptosis Pathway Perforin/granzyme apoptosis pathway is the primary signaling pathway used by cytotoxic lymphocytes to eliminate virus-infected and/or transformed cells. Studies in gene-disrupted mice indicate that perforin, in combination with granzyme, could induce apoptosis. It is vital for cytotoxic effector function and has an indispensable, but an undefined role in granzyme-mediated apoptosis. Perforin is a pore-forming protein and also known as cytoplasmic granule toxins. Granzyme is a family of structurally related serine proteases stored within the cytotoxic granules of cytotoxic lymphocytes (CLs). Perforin and granzyme induce target-cell apoptosis cooperatively (Figure 1). Granzyme is necessary for triggering apoptosis of target cells, but they depend on being appropriately delivered by perforin. Both perforin and granzyme bind to the target-cell surface as part of a single macromolecular complex associated with serglycin, which further diminishes the probability of passive diffusion of granzymes. In humans, there are granzyme A, B, H, K, and M, while in mice there are granzyme A, B, C, D, E, F, G, K, L, M, and N. Granzyme A (GrA) and granzyme B (GrB) are the most abundant granzymes and have been the most studied. The functions of granzymes A and B in inducing target-cell apoptosis have been investigated extensively in vitro, and they are better understood than the role of perforin at the molecular level. https://www.creative-diagnostics.com/perforin-granzyme-apoptosis-pathway.htm