The Salmonella enterica giant adhesin SiiE binds to polarized epithelial cells in a lectin‐like manner. (13th January 2014)

• Record Type: Journal Article
• Authors: Wagner, Carolin; Barlag, Britta; Gerlach, Roman G.; Deiwick, Jörg; Hensel, Michael
• Is Part Of: Cellular microbiology. Volume 16:Number 6(2014:Jun.)
• Page Start: 962
• Page End: 975
• Publication Date: 2014-01-13
• Subjects: Microbiology -- Periodicals; Cytology -- Periodicals; Host-parasite relationships -- Periodicals; Microbiology -- Periodicals; Cells -- Periodicals; Microbiologie -- Périodiques; Microbiologie; Relation hôte-parasite; Cytologie; Cellule; Réponse cellulaire; Ressource Internet (Descripteur de forme); Périodique électronique (Descripteur de forme); 579.05
• DOI: 10.1111/cmi.12253
• Languages: English
• ISSNs: 1462-5814

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>The invasion of polarized epithelial cells by <italic>S</italic><italic>almonella enterica</italic> requires the cooperative activity of the <italic>S</italic><italic>almonella</italic> pathogenicity island (SPI) 1‐encoded type III secretion system (T3SS) and the SPI4‐encoded giant non‐fimbrial adhesin SiiE. SiiE is a highly repetitive protein composed of 53 bacterial Ig (BIg) domains and mediates binding to the apical side of polarized epithelial cells. We analysed the binding properties of SiiE and observed lectin‐like activity. SiiE‐dependent cell invasion can be ablated by chemical or enzymatic deglycosylation. Lectin blockade experiments revealed that SiiE binding is specific for glycostructures with terminal <italic>N</italic>‐acetyl‐glucosamine (GlcNAc) and/or α 2, 3‐linked sialic acid. In line with these data, we found that SiiE‐expressing <italic>S</italic><italic>almonella</italic> bind to the GlcNAc polymer chitin. Various recombinant SiiE fragments were analysed for host cell binding. We observed that C‐terminal portions of SiiE bind to the apical side of polarized cells and the intensity of binding increases with the number of BIg domains present in the recombinant proteins. Based on these results, we propose that SiiE mediates multiple interactions per molecule with glycoproteins and/or glycosylated phospholipids present in the apical membrane of polarized epithelial cells. Thisintimate binding enables the subsequent function of the SPI1‐T3SS, resulting in host cell invasion.</p> </abstract>