Biosynthesis of granulysin, a novel cytolytic molecule.
Granulysin is a newly described lytic molecule expressed by CTL and NK cells. Three mRNA (519, 520, and 522) and two protein products of 15 and 9 kDa are encoded by the granulysin gene. Stable transfectants overexpressing the predominate 520 mRNA were generated to determine the protein products originating from the translation of this message. A transfectant of the NK cell tumor YT overexpressed both 15 and 9 kDa proteins while a transfectant of the T cell tumor HuT78 produced mainly 15 kDa granulysin. Thus the 520 mRNA is sufficient for production of both 15 and 9 kDa granulysin. 9 kDa granulysin accumulated via post-translational processing of 15 kDa protein and was present intracellularly but not in the cell culture supernatant, indicating specific retention of the 9 kDa protein. An inhibitor of granule acidification, concanamycin A, blocked the processing of 15 kDa granulysin to the 9 kDa form. A deduced structural difference between the two forms of the protein and a decrease in lytic activity of 9 kDa granulysin at granule pH suggest two mechanisms by which a granulysin expressing cell is protected from autolysis during the biosynthesis of this potentially harmful molecule.
Hanson
D A
DA
Department of Pediatrics, Stanford University School of Medicine, CA 94305-5208, USA.
Kaspar
A A
AA
Poulain
F R
FR
Krensky
A M
AM
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis* / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007694:Killer Cells, Natural / Q000737:chemistry* / Q000276:immunology; D007700:Kinetics; D018942:Macrolides; D011233:Precipitin Tests; D013602:T-Lymphocytes, Cytotoxic / Q000737:chemistry* / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
D000900:Anti-Bacterial Agents; D000945:Antigens, Differentiation, T-Lymphocyte; D004791:Enzyme Inhibitors; C075005:GNLY protein, human; D018942:Macrolides; C036978:concanamycin A