Structure, Function, and Assembly of Adhesive Organelles by Uropathogenic Bacteria

Abstract

Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities such as biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hairlike fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections.

Comparative genomics of transport proteins in probiotic and pathogenic Escherichia coli and Salmonella enterica strains

“…Both probiotic strains contain cytotoxic fimbrial subunit transporters, though the relevance of these systems is not clear since E. coli strains produce dozens of fimbriae with a variety of functions in adhesion, biofilm formation, motility, conjugation, and virulence [36, 37]. Consistent with previous studies, E. coli Nissle contains an additional toxin, colicin V, which is toxic to other bacteria, but not to humans [13].…”

Autotransporter Adhesins in Escherichia coli Pathogenesis

“…These adhesins are anchored to the surface of the outer membrane and due to their reduced size, they allow more intimate contact between the bacterial cell surface and specific substrates . One of the major classes of non‐fimbrial adhesion factors are the autotransporter (AT) adhesins . These surface proteins belong to the AT superfamily of proteins, which are the largest group of cell surface and secreted proteins in Gram‐negative bacteria .…”

Improving the Switching Capacity of Glyco‐Self‐Assembled Monolayers on Au(111)

“…Carbohydrates are ligands of a class of proteins called lectins, which apparently govern most cell–cell interactions through specific carbohydrate–lectin interactions. For example, many Enterobacteriaceae , such as Escherichia coli ( E. coli ), accomplish firm adhesion to the surface of their host cells through lectins, which are constituents of adhesive organelles projecting from the bacterial surface called fimbriae (or pili) . Among the most important bacterial fimbriae are so‐called type 1 fimbriae, which mediate adhesion to terminal α‐ d ‐mannopyranoside components of the glycocalyx through the type 1‐fimbrial lectin FimH …”

“…For example, many Enterobacteriaceae, such as Escherichia coli (E. coli), accomplish firm adhesion to the surface of their host cells through lectins, which are constituents of adhesive organelles projecting from the bacterial surface called fimbriae (or pili). [3] Among the most important bacterial fimbriae are so-called type 1 fimbriae, which mediate adhesion to terminal a-d-mannopyranoside components of the glycocalyx through the type 1-fimbrial lectin FimH. [4] Many principles of the highly complex supramolecular interactions leading to cell adhesion are still not well understood.…”