A rat gene homologous to human granule membrane protein 17 is expressed by natural killer cells, CD8 super(+) T cells, and a mast cell line

The human granule membrane protein of 17 000 M sub(r) (GMP-17), formerly called p15-TIA-1, localizes to the membranes of cytotoxic granules of natural killer (NK) cells and translocates to the plasma membrane upon degranulation and target cell lysis. The amino acid sequence of GMP-17 is identical to those predicted by two human cDNA clones previously isolated from NK cells [NKG7] and mononuclear cells from a chronic myelogenous leukemia patient [GIG-1], respectively. As a result of random characterization of several clones obtained from a rat NK-cell cDNA library, we isolated a cDNA with 73.3% nucleotide identity and 71.5% amino acid identity to human GMP-17/NKG7/GIG-1. Although the rat GMP-17 cDNA predicts a protein similar to human GIG-1 throughout, it differes considerably in its C-terminal half from the first reported human NKG7 sequence. The latter has been altered after re-evaluation of the material, and brought to be identical to GIG-1 except for one nucleotide (silent mutation).