Publication Date:
2010-11-03
Description:
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. 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). 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 perforin-like (MACPF)/cholesterol dependent cytolysin (CDC) domain 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(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. 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 /〉〈span class="detail_caption"〉Notes: 〈/span〉Law, Ruby H P -- Lukoyanova, Natalya -- Voskoboinik, Ilia -- Caradoc-Davies, Tom T -- Baran, Katherine -- Dunstone, Michelle A -- D'Angelo, Michael E -- Orlova, Elena V -- Coulibaly, Fasseli -- Verschoor, Sandra -- Browne, Kylie A -- Ciccone, Annette -- Kuiper, Michael J -- Bird, Phillip I -- Trapani, Joseph A -- Saibil, Helen R -- Whisstock, James C -- 079605/Wellcome Trust/United Kingdom -- BB/D008573/1/Biotechnology and Biological Sciences Research Council/United Kingdom -- Arthritis Research UK/United Kingdom -- Biotechnology and Biological Sciences Research Council/United Kingdom -- Wellcome Trust/United Kingdom -- England -- Nature. 2010 Nov 18;468(7322):447-51. doi: 10.1038/nature09518. Epub 2010 Oct 31.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biochemistry and Molecular Biology, Monash University, Clayton, Melbourne, Victoria 3800, Australia.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21037563" target="_blank"〉PubMed〈/a〉
Keywords:
Animals
;
Cell Membrane/*metabolism
;
Cholesterol/metabolism
;
Cryoelectron Microscopy
;
Crystallography, X-Ray
;
Epidermal Growth Factor/chemistry
;
Granzymes/metabolism
;
Humans
;
Lymphocytes/*metabolism
;
Mice
;
Models, Molecular
;
Pore Forming Cytotoxic Proteins/*chemistry/genetics/*metabolism/ultrastructure
;
Protein Structure, Tertiary
Print ISSN:
0028-0836
Electronic ISSN:
1476-4687
Topics:
Biology
,
Chemistry and Pharmacology
,
Medicine
,
Natural Sciences in General
,
Physics
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