title: Structural and functional importance of outer membrane proteins in Vibrio cholerae flagellum.
abstract: Vibrio cholerae has a sheath-covered monotrichous flagellum that is known to contribute to virulence. Although the structural organization of the V. cholerae flagellum has been extensively studied, the involvement of outer membrane proteins as integral components in the flagellum still remains elusive. Here we show that flagella produced by V. cholerae O1 El Tor strain C6706 were two times thicker than those from two other Gram-negative bacteria. A C6706 mutant strain (SSY11) devoid of two outer membrane proteins (OMPs), OmpU and OmpT, produced thinner flagella. SSY11 showed significant defects in the flagella-mediated motility as compared to its parental strain. Moreover, increased shedding of the flagella-associated proteins was observed in the culture supernatant of SSY11. This finding was also supported by the observation that culture supernatants of the SSY11 strain induced the production of a significantly higher level of IL-8 in human colon carcinoma HT29 and alveolar epithelial A549 cells than those of the wild-type C6706 strain. These results further suggest a definite role of these two OMPs in providing the structural integrity of the V. cholerae flagellum as part of the surrounding sheath.
authors.affiliation: Department of Microbiology and Immunology, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea.
authors.forename: Wasimul
authors.initials: W
authors.lastname: Bari
authors.forename: Kang-Mu
authors.initials: KM
authors.lastname: Lee
authors.forename: Sang Sun
authors.initials: SS
authors.lastname: Yoon
mesh_terms: D018829:Adhesins, Bacterial / Q000032:analysis* / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D005407:Flagella / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure; D017353:Gene Deletion; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D008124:Locomotion; D018272:Porins / Q000032:analysis* / Q000235:genetics / Q000502:physiology*; D041241:Vibrio cholerae O1 / Q000737:chemistry* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D018829:Adhesins, Bacterial; D001426:Bacterial Proteins; D016209:Interleukin-8; C096349:OmpU protein, Vibrio cholerae; D018272:Porins; C405564:ompT protein, bacteria