The PRF1 gene at 10q22.1 codes for the 555 amino acid perforin-1 a component of cytolytic granules that is key to secretory granule-dependent cell death. This is used in the bodies natural defense against virus-infected or neoplastic cells. It is stored in the cytoplasmic granules of cytolytic T-lymphocytes and secreted into the space between the T-lymphocyte and target cell. Its calcium-bound form then inserts into the cell membrane of the target cells, forming a oligomerized pore from transmembrane beta-strands. Cytotoxic granzymes then enter the target cell resulting in cytolysis and apoptosis.
Mutations of PRF1 cause familial haemophagocytic lymphohistiocytosis 2.