Eukaryotic Cell
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Other Versions of this Article:
EC.00094-07v1
6/7/1130    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Meléndez-López, S. G.
Right arrow Articles by Reed, S. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Meléndez-López, S. G.
Right arrow Articles by Reed, S. L.

 Previous Article  |  Next Article 

Eukaryotic Cell, July 2007, p. 1130-1136, Vol. 6, No. 7
1535-9778/07/$08.00+0     doi:10.1128/EC.00094-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Use of Recombinant Entamoeba histolytica Cysteine Proteinase 1 To Identify a Potent Inhibitor of Amebic Invasion in a Human Colonic Model{triangledown}

Samuel G. Meléndez-López,1 Scott Herdman,1 Ken Hirata,1 Min-Ho Choi,2 Youngchool Choe,3 Charles Craik,3 Conor R. Caffrey,4 Elisabeth Hansell,4 Bibiana Chávez-Munguía,5 Yen Ting Chen,6 William R. Roush,6 James McKerrow,4 Lars Eckmann,1 Jianhua Guo,7 Samuel L. Stanley Jr.,7 and Sharon L. Reed1*

Departments of Pathology and Medicine, University of California, San Diego, San Diego, California 92103-8416,1 Department of Parasitology and Tropical Medicine, Seoul National University College of Medicine, Seoul 110-799, South Korea,2 Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California 94143,3 Sandler Center for Basic Research in Parasitic Diseases, University of California, San Francisco, San Francisco, California 94143,4 Departamento de Patología Experimental, Centro de Investigación y de Estudios Avanzados del I.P.N., México City, México 07000,5 Departments of Chemistry and Biochemistry, Scripps Research Institute, Jupiter, Florida 33458,6 Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 631107

Received 23 March 2007/ Accepted 5 May 2007

Cysteine proteinases are key virulence factors of the protozoan parasite Entamoeba histolytica. We have shown that cysteine proteinases play a central role in tissue invasion and disruption of host defenses by digesting components of the extracellular matrix, immunoglobulins, complement, and cytokines. Analysis of the E. histolytica genome project has revealed more than 40 genes encoding cysteine proteinases. We have focused on E. histolytica cysteine proteinase 1 (EhCP1) because it is one of two cysteine proteinases unique to invasive E. histolytica and is highly expressed and released. Recombinant EhCP1 was expressed in Escherichia coli and refolded to an active enzyme with a pH optimum of 6.0. We used positional-scanning synthetic tetrapeptide combinatorial libraries to map the specificity of the P1 to P4 subsites of the active site cleft. Arginine was strongly preferred at P2, an unusual specificity among clan CA proteinases. A new vinyl sulfone inhibitor, WRR483, was synthesized based on this specificity to target EhCP1. Recombinant EhCP1 cleaved key components of the host immune system, C3, immunoglobulin G, and pro-interleukin-18, in a time- and dose-dependent manner. EhCP1 localized to large cytoplasmic vesicles, distinct from the sites of other proteinases. To gain insight into the role of secreted cysteine proteinases in amebic invasion, we tested the effect of the vinyl sulfone cysteine proteinase inhibitors K11777 and WRR483 on invasion of human colonic xenografts. The resultant dramatic inhibition of invasion by both inhibitors in this human colonic model of amebiasis strongly suggests a significant role of secreted amebic proteinases, such as EhCP1, in the pathogenesis of amebiasis.

* Corresponding author. Mailing address: Division of Infectious Diseases, UCSD Medical Center, 200 W. Arbor Dr., San Diego, CA 92103-8416. Phone: (619) 543-6146. Fax: (619) 543-6614. E-mail: slreed{at}ucsd.edu

{triangledown} Published ahead of print on 18 May 2007.

Eukaryotic Cell, July 2007, p. 1130-1136, Vol. 6, No. 7
1535-9778/07/$08.00+0     doi:10.1128/EC.00094-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.





HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Appl. Environ. Microbiol. Infect. Immun. J. Bacteriol.
Mol. Cell Biol. Microbiol. Mol. Biol. Rev. ALL ASM JOURNALS
Copyright © 2007 by the American Society for Microbiology.