Escherichia coli DraE adhesin-associated bacterial internalization by epithelial cells is promoted independently by decay-accelerating factor and carcinoembryonic antigen-related cell adhesion molecule binding and does not require the DraD invasin.
The Dr family of Escherichia coli adhesins are virulence factors associated with diarrhea and urinary tract infections. Dr fimbriae are comprised of two subunits. DraE/AfaE represents the major structural, antigenic, and adhesive subunit, which recognizes decay-accelerating factor (DAF) and carcinoembryonic antigen (CEA)-related cell adhesion molecules (CEACAMs) CEA, CEACAM1, CEACAM3, and CEACAM6 as binding receptors. The DraD/AfaD subunit caps fimbriae and has been implicated in the entry of Dr-fimbriated E. coli into host cells. In this study, we demonstrate that DAF or CEACAM receptors independently promote DraE-mediated internalization of E. coli by CHO cell transfectants expressing these receptors. We also found that DraE-positive recombinant bacteria adhere to and are internalized by primary human bladder epithelial cells which express DAF and CEACAMs. DraE-mediated bacterial internalization by bladder cells was inhibited by agents which disrupt lipid rafts, microtubules, and phosphatidylinositol 3-kinase (PI3K) activity. Immunofluorescence confocal microscopic examination of epithelial cells detected considerable recruitment of caveolin, beta(1) integrin, phosphorylated ezrin, phosphorylated PI3K, and tubulin, but not F-actin, by cell-associated bacteria. Finally, we demonstrate that the DraD subunit, previously implicated as an "invasin," is not required for beta(1) integrin recruitment or bacterial internalization.
Korotkova
Natalia
N
Department of Microbiology, University of Washington, Seattle, Washington 98195-7242, USA.
Yarova-Yarovaya
Yuliya
Y
Tchesnokova
Veronika
V
Yazvenko
Nina
N
Carl
Mike A
MA
Stapleton
Ann E
AE
Moseley
Steve L
SL
D018829:Adhesins, Bacterial / Q000502:physiology*; D000818:Animals; D001422:Bacterial Adhesion; D018958:CD55 Antigens / Q000378:metabolism*; D016466:CHO Cells; D018938:Caco-2 Cells; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D004847:Epithelial Cells / Q000382:microbiology*; D004926:Escherichia coli / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000502:physiology*; D036781:Fimbriae Proteins / Q000502:physiology*; D006801:Humans; D011485:Protein Binding
D018829:Adhesins, Bacterial; D018958:CD55 Antigens; D015815:Cell Adhesion Molecules; C530426:DraD invasin, E coli; C465563:DraE protein, E coli; D029968:Escherichia coli Proteins; D036781:Fimbriae Proteins