Bacteroides fragilis toxin rearranges the actin cytoskeleton of HT29/C1 cells without direct proteolysis of actin or decrease in F-actin content
✍ Scribed by Saidi, Roxan F. ;Jaeger, Kristin ;Montrose, Marshall H. ;Wu, Shaoguang ;Sears, Cynthia L.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 245 KB
- Volume
- 37
- Category
- Article
- ISSN
- 0886-1544
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✦ Synopsis
Enterotoxigenic strains of B. fragilis associated with childhood diarrhea produce a 20 kD zinc metalloprotease toxin (BFT). BFT is reported to cleave G-actin in vitro and also causes dramatic rounding and rearrangement of the F-actin cytoskeleton in human intestinal epithelial cell lines (HT29 and HT29/C1). To test the hypothesis that the proteolysis of cellular actin by BFT in vivo may contribute to these alterations in morphology and cytoskeletal architecture, we assessed the F-actin content and the arrangement of the F-and G-actin cytoskeleton in BFT-treated HT29/C1 cells by spectrofluorimetry, confocal microscopy, and immunoblotting. BFT-treated cells were compared to cells treated with C. diffıcile toxin A (CDA) or cytochalasin D. Using spectrofluorimetric quantification, the F-actin content of BFT-and cytochalasin D-treated cells was unchanged in contrast to a significant decrease in CDA-treated cells. By confocal microscopy, the arrangement of F-and G-actin in all treated cells was markedly different than control cells. There was no change in the immunoblotting pattern of actin in the Triton-soluble or -insoluble cellular fractions of BFT-treated HT29/C1 cells. We conclude that BFT alters the F-and G-actin cytoskeletal architecture of HT29/C1 cells without direct proteolysis of actin or decrease in F-actin content. Cell Motil.