cytotoxic granules

Lytic granules harbour many of the dangerous apoptosis-inducing molecules of the immune system, including perforin, granzymes and Fas ligand. Safe transport, storage and release of these lytic components is vital.

As a secretory lysosome, the lytic granule is able to accomplish these roles, as well as conferring the lysosomal functions of cytotoxic T lymphocytes and natural killer cells. Secretory lysosomes are common to many other haemopoietic cells and also melanocytes.

Many of the proteins used in lysosomal secretion are found in both melanocytes and hemopoietic cells, and are dysfunctional in genetic diseases with defects in these proteins.

The genetically heterogeneous Hermansky-Pudlak syndrome represents an excellent model for revealing proteins involved in secretory lysosome functioning.

However, studies of this disease reveal differences between the various different types of secretory lysosomes, including lytic granules.

See also

 UNC13D
 STX11
 RAB5A
 SNARE

References

 Hong W. Cytotoxic T lymphocyte exocytosis: bring on the SNAREs! Trends Cell Biol. 2005 Dec;15(12):644-50. PMID: 16260137

 Clark R, Griffiths GM. Lytic granules, secretory lysosomes and disease. Curr Opin Immunol. 2003 Oct;15(5):516-21. PMID: 14499259

 Raja SM, Metkar SS, Froelich CJ. Cytotoxic granule-mediated apoptosis: unraveling the complex mechanism. Curr Opin Immunol. 2003 Oct;15(5):528-32. PMID: 14499261

 Catalfamo M, Henkart PA. Perforin and the granule exocytosis cytotoxicity pathway. Curr Opin Immunol. 2003 Oct;15(5):522-7. PMID: 14499260

 Trapani JA, Davis J, Sutton VR, Smyth MJ. Proapoptotic functions of cytotoxic lymphocyte granule constituents in vitro and in vivo. Curr Opin Immunol. 2000 Jun;12(3):323-9. PMID: 10781403