Source:http://linkedlifedata.com/resource/umls/id/C1512273
NCI: One mechanism used by cytotoxic T cells to kill tumor cells and virus-infected cells is the release of perforin and granzyme proteins. Perforin proteins form pores in the membranes of the attacked cell, allowing the entry of Granzyme A and Granzyme B. Granzyme B induces caspase activation and cleavage of factors like ICAD, releasing DFF40 to fragment DNA, one of the hallmarks of apoptotic cell death. Granzyme A is also an abundant granzyme released by cytotoxic T cells and is important in cytotoxic T cell induced apoptosis, activating caspase independent pathways. Once in a cell, Granzyme A activates DNA nicking by the recently identified DNAse NM23-H1, a tumor suppressor gene product whose expression is reduced in transformed, metastatic cells. The previous identification of NM23-H1 as a tumor suppressor indicates that its DNAse activity plays an important role in immune surveillance to prevent cancer through the induction of tumor cell apoptosis. The activation of NM23-H1 occurs indirectly, through the