Granzyme A (GzmA, , ''CTLA3'', ''HuTPS'', ''T-cell associated protease 1'', ''cytotoxic T lymphocyte serine protease'', ''TSP-1'', ''T-cell derived serine proteinase'') is a
tryptase
Tryptase () is the most abundant secretory granule-derived serine proteinase contained in mast cells and has been used as a marker for mast cell activation. Club cells contain tryptase, which is believed to be responsible for cleaving the hemagglu ...
and is one of the five
granzyme
Granzymes are serine proteases released by cytoplasmic granules within cytotoxic T cells and natural killer (NK) cells. They induce programmed cell death (apoptosis) in the target cell, thus eliminating cells that have become cancerous or are infe ...
s encoded in the human genome.
In humans, GzmA is encoded by the GZMA
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
in proximity to the
GZMK gene on chromosome 5. This enzyme is present in
cytotoxic T lymphocyte (CTL) granules.
GzmA cleaves proteins after arginine or lysine basic residues. In CTL-targeted cells, it activates caspase-independent programmed cell death pathways that are unique and parallel to that of
Granzyme B
Granzyme B (GrB) is one of the serine protease granzymes most commonly found in the granules of natural killer cells (NK cells) and cytotoxic T cells. It is secreted by these cells along with the pore forming protein perforin to mediate apoptos ...
, although some substrates such as PARP-1 and lamin B are shared with Granzyme B. Substrates of GzmA include Pro-IL-1β, NDUFS3, SET, APE1, and Ku70 among others. ''In vitro'' studies suggest that GzmA may have less cytotoxic capabilities than GzmB.
In colorectal cancer, GzmA was associated with promotion of cancer development, which may be due to activation of inflammation-inducing cytokines from macrophages.
See also
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GZMA
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GZMK
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GZMB
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GZMH
References
Further reading
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External links
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EC 3.4.21