This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Saved Citations Download to citation manager Request Permissions Request Reprints Add to My Marked Citations Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Citing Articles via Scopus Google Scholar Articles by Haiko, J. Articles by Korhonen, T. K. Search for Related Content PubMed PubMed Citation Articles by Haiko, J. Articles by Korhonen, T. K. Social Bookmarking                         What's this?

Invited review: Breaking barriers — attack on innate immune defences by omptin surface proteases of enterobacterial pathogens

General Microbiology, Faculty of Biosciences, University of Helsinki, Helsinki, Finland

Marjo Suomalainen

General Microbiology, Faculty of Biosciences, University of Helsinki, Helsinki, Finland

Teija Ojala

General Microbiology, Faculty of Biosciences, University of Helsinki, Helsinki, Finland

Kaarina Lähteenmäki

Research and Development, Red Cross Finland Blood Service, Helsinki, Finland

Timo K. Korhonen

General Microbiology, Faculty of Biosciences, University of Helsinki, Helsinki, Finland, timo.korhonen{at}helsinki.fi

The omptin family of Gram-negative bacterial transmembrane aspartic proteases comprises surface proteins with a highly conserved β-barrel fold but differing biological functions. The omptins OmpT of Escherichia coli, PgtE of Salmonella enterica, and Pla of Yersinia pestis differ in their substrate specificity as well as in control of their expression. Their functional differences are in accordance with the differing pathogenesis of the infections caused by E. coli, Salmonella, and Y. pestis, which suggests that the omptins have adapted to the life-styles of their host species. The omptins Pla and PgtE attack on innate immunity by affecting the plasminogen/plasmin, complement, coagulation, fibrinolysis, and matrix metalloproteinase systems, by inactivating antimicrobial peptides, and by enhancing bacterial adhesiveness and invasiveness. Although the mechanistic details of the functions of Pla and PgtE differ, the outcome is the same: enhanced spread and multiplication of Y. pestis and S. enterica in the host. The omptin OmpT is basically a housekeeping protease but it also degrades cationic antimicrobial peptides and may enhance colonization of E. coli at uroepithelia. The catalytic residues in the omptin molecules are spatially conserved, and the differing polypeptide substrate specificities are dictated by minor sequence variations at regions surrounding the catalytic cleft. For enzymatic activity, omptins require association with lipopolysaccharide on the outer membrane. Modification of lipopolysaccharide by in vivo conditions or by bacterial gene loss has an impact on omptin function. Creation of bacterial surface proteolysis is thus a coordinated function involving several surface structures.

Key Words: surface proteolysis • plague • salmonellosis • Escherichia coli • plasminogen activator • gelatinase • antimicrobial peptides

Innate Immunity, Vol. 15, No. 2, 67-80 (2009)
DOI: 10.1177/1753425909102559


CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				J. Haiko, M. Kukkonen, J. J. Ravantti, B. Westerlund-Wikstrom, and T. K. Korhonen The Single Substitution I259T, Conserved in the Plasminogen Activator Pla of Pandemic Yersinia pestis Branches, Enhances Fibrinolytic Activity J. Bacteriol., August 1, 2009; 191(15): 4758 - 4766. [Abstract] [Full Text] [PDF]