Back to Search
Start Over
The structural basis for membrane binding and pore formation by lymphocyte perforin
- Source :
- Nature. November 18, 2010, Vol. 468 Issue 7322, p447, 7 p.
- Publication Year :
- 2010
-
Abstract
- Natural killer cells and cytotoxic T lymphocytes accomplish the critically important function of killing virus-infected and neoplastic cells. They do this by releasing the pore-forming protein perforin and granzyme proteases from cytoplasmic granules into the cleft formed between the abutting killer and target cell membranes. Perforin, a 67-kilodalton multidomain protein, oligomerizes to form pores that deliver the pro-apoptopic granzymes into the cytosol of the target cell (1-6). The importance of perforin is highlighted by the fatal consequences of congenital perforin deficiency, with more than 50 different perforin mutations linked to familial haemophagocytic lymphohistiocytosis (type 2 FHL) (7). Here we elucidate the mechanism of perforin pore formation by determining the X-ray crystal structure of monomeric murine perforin, together with a cryo-electron microscopy reconstruction of the entire perforin pore. Perforin is a thin 'key-shaped' molecule, comprising an amino-terminal membrane attack complex perforinlike (MACPF)/cholesterol dependent cytolysin (CDC) domain (8,9) followed by an epidermal growth factor (EGF) domain that, together with the extreme carboxy-terminal sequence, forms a central shelf-like structure. A C-terminal C2 domain mediates initial, [Ca.sup.2+]-dependent membrane binding. Most unexpectedly, however, electron microscopy reveals that the orientation of the perforin MACPF domain in the pore is inside-out relative to the subunit arrangement in CDCs (10,11). These data reveal remarkable flexibility in the mechanism of action of the conserved MACPF/CDC fold and provide new insights into how related immune defence molecules such as complement proteins assemble into pores.<br />The sequence similarity between perforin and complement components C6-C9 of the membrane attack complex strongly suggests that two major branches of the mammalian immune system utilize a pore-forming MACPF fold [...]
Details
- Language :
- English
- ISSN :
- 00280836
- Volume :
- 468
- Issue :
- 7322
- Database :
- Gale General OneFile
- Journal :
- Nature
- Publication Type :
- Academic Journal
- Accession number :
- edsgcl.242962977
- Full Text :
- https://doi.org/10.1038/nature09518