Figure 1.

ClpV is an essential energizing component of T6SS. (A) Culture supernatants of V. cholerae V52 wild-type (V.c. wt) and V. cholerae V52 ΔclpV and ΔicmF mutant cells were separated by 2D gel electrophoresis followed by silver staining. Protein spots that were specifically present in V.c. wt but missing in V.c. ΔclpV and V.c. ΔicmF mutants (arrows) were identified by mass spectrometry as full-length Hcp or Hcp degradation products. (B) The deficiencies of V.c. ΔclpV and V.c. ΔicmF mutants in Hcp secretion were verified by immunoblot analysis using Hcp-specific antibodies. Sup: culture supernatant; total: total cell extract. (C, D) Complementation of the V.c. ΔclpV secretion defect by plasmid-encoded clpV and clpV-DWB using Hcp- or VgrG2-specific antibodies. ClpV levels were monitored by immunoblot analysis using ClpV-specific antibodies.