Bacillus anthracis, the causative agent of anthrax, is one of the six CDC category A agents considered to be those which would cause the most adverse public health impact if used in a biological attack. Highly virulent forms of B. anthracis secrete two toxins, lethal toxin (LeTx) and edema toxin (EdTx), which are thought to be primarily responsible for the major symptoms and death associated with anthrax. Entry of both types of toxin into cells is mediated by the bacterial protective antigen (PA) subunit. In an effort to understand how these toxins enter cells we have identified two distinct cellular receptors for PA, Anthrax Toxin Receptor/Tumor Endothelial Marker-8 (ATR/TEM8) and Capillary Morphogenesis Protein-2 (CMG2). We have also developed soluble receptor decoys as candidate antitoxins for the treatment of anthrax. The research described in this proposal will build upon these landmark findings to further our understanding of anthrax toxin entry.
The first aim will investigate the role played by the receptors in trafficking toxin to distinct sites in the cell that are associated with marked differences in toxin stability.
The second aim will seek to develop a cell-free system that will allow the dissection of the molecular mechanism of anthrax toxin translocation.
The third aim will investigate whether anthrax toxin, like other bacterial toxins, can be targeted to other types of cell surface receptors (surrogate receptors). This information will provide important insights into the critical parameters required for toxin entry.
The fourth aim will seek to establish whether the DNI-class of anthrax antitoxins can block toxin entry that is mediated by surrogate receptors. Together, this body of work will contribute significantly to our understanding of the cell biology of anthrax toxin entry. This information in turn may reveal new targets for therapeutic intervention in the treatment of disease, and may pre-empt the actions of bioterrorists who seek to target PA to surrogate cell surface receptors in an effort to evade anti-PA antibody and soluble receptor decoy-based antitoxins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI048489-09
Application #
7248792
Study Section
Special Emphasis Panel (ZRG1-IDM-A (90))
Program Officer
Breen, Joseph J
Project Start
2000-08-15
Project End
2009-06-30
Budget Start
2007-07-01
Budget End
2008-06-30
Support Year
9
Fiscal Year
2007
Total Cost
$579,532
Indirect Cost
Name
Salk Institute for Biological Studies
Department
Type
DUNS #
078731668
City
La Jolla
State
CA
Country
United States
Zip Code
92037
Reeves, C V; Dufraine, J; Young, J A T et al. (2010) Anthrax toxin receptor 2 is expressed in murine and tumor vasculature and functions in endothelial proliferation and morphogenesis. Oncogene 29:789-801
Ryan, Patricia L; Young, John A T (2008) Evidence against a human cell-specific role for LRP6 in anthrax toxin entry. PLoS One 3:e1817
Scobie, Heather M; Marlett, John M; Rainey, G Jonah A et al. (2007) Anthrax toxin receptor 2 determinants that dictate the pH threshold of toxin pore formation. PLoS One 2:e329
Sun, Jianjun; Vernier, Gregory; Wigelsworth, Darran J et al. (2007) Insertion of anthrax protective antigen into liposomal membranes: effects of a receptor. J Biol Chem 282:1059-65
Scobie, Heather M; Wigelsworth, Darran J; Marlett, John M et al. (2006) Anthrax toxin receptor 2-dependent lethal toxin killing in vivo. PLoS Pathog 2:e111
Keim, Paul; Mock, Michele; Young, John et al. (2006) The International Bacillus anthracis, B. cereus, and B. thuringiensis Conference, ""Bacillus-ACT05"". J Bacteriol 188:3433-41
Scobie, Heather M; Young, John A T (2005) Interactions between anthrax toxin receptors and protective antigen. Curr Opin Microbiol 8:106-12
Rainey, G Jonah A; Wigelsworth, Darran J; Ryan, Patricia L et al. (2005) Receptor-specific requirements for anthrax toxin delivery into cells. Proc Natl Acad Sci U S A 102:13278-83
Lacy, D Borden; Wigelsworth, Darran J; Scobie, Heather M et al. (2004) Crystal structure of the von Willebrand factor A domain of human capillary morphogenesis protein 2: an anthrax toxin receptor. Proc Natl Acad Sci U S A 101:6367-72
Lacy, D Borden; Wigelsworth, Darran J; Melnyk, Roman A et al. (2004) Structure of heptameric protective antigen bound to an anthrax toxin receptor: a role for receptor in pH-dependent pore formation. Proc Natl Acad Sci U S A 101:13147-51

Showing the most recent 10 out of 14 publications