Roles of Flagellar Hook-Associated Proteins in Vibrio vulnificus Motility and Virulence.
- Author:
Soo Young KIM
1
;
Hye Young HONG
;
Joon Haeng RHEE
;
Sun Sik CHUNG
Author Information
- Publication Type:Original Article
- Keywords: Vibrio vulnificus; Flagella; Hook associated proteins; Motility; Virulence
- MeSH: Bacterial Proteins; Blotting, Western; Electrons; Flagella; Flagellin; Genome; HeLa Cells; Humans; Proteins; Sprains and Strains; Vibrio; Vibrio vulnificus
- From:Journal of Bacteriology and Virology 2008;38(1):1-10
- CountryRepublic of Korea
- Language:English
- Abstract: The bacterial flagellar structure can be divided into the basal body, the hook and the filament. Three minor components called hook associated proteins (HAP1, HAP2 and HAP3) form a junction between the hook and the filament (HAP1 and HAP3) and a capping structure at the distal end of flagellar filament (HAP2). Vibrio vulnificus is a halophilic pathogenic bacterium that is locomotive by means of a polar flagellum. From a V. vulnificus genome sequencing project, we obtained sequences of V. vulnificus flgK (Vv-flgK), flgL (Vv-flgL), and flaH (Vv-flaH) genes that encode HAP1, HAP3, and HAP2, respectively. To investigate roles of the HAP proteins, deletion mutants of the Vv-flgK, Vv-flgL and Vv-flaH were constructed. Electron microscopic analysis showed that the Vv-flgK or Vv-flgL mutant did not produce an intact polar flagellum while the Vv-flaH mutant produced a fragile flagellar structure. Western blot analysis against a major polar flagellin proposed that the null HAP1 and HAP3 mutations resulted in a failure of normal flagellar assembly since flagellins produced by the mutants were secreted out in the culture supernatants without long flagellar filaments. Motility was completely abolished by a single mutation in HAP1 or HAP3, and the HAP2 mutant showed a decreased motility. Also each of the mutants showed an impaired cytotoxicity and adherence to HeLa cell compared with the isogenic wild type strain. LD(50) increased by 10- and 11-fold in the V. vulnificus HAP3 and HAP2 mutant, respectively. These results suggest that the HAP proteins play important roles in polar flagellation and the virulence of V. vulnificus.
