Figure 3. CrvA filaments drive V. cholerae curvature.

(A–B) Changing medium osmolality demonstrates that CrvA localization precedes curvature formation. See Figure S7D for more on osmolarity quantification.

(A) Cells grown in LB are curved with CrvA-GFP filaments, while cells grown in hyperosmotic media (red) are straight with more diffuse CrvA-GFP signal. Cells transferred from hyperosmotic media into LB (green fade) exhibit CrvA-GFP filament formation within 30 min (black arrow), preceding curvature formation; scale bar = 2 μm.

(B) Quantification of 2D centerline curvature dynamics reveals a delay in curvature recovery following transfer from LB into hyperosmotic media (black arrow). Means of five runs ± SEM.

(C–F) CrvA-GFP filaments correlate with increased 3D centerline curvature. See Figure S3A–C for an explanation of curvature quantification.

(C) A maximum intensity projection from a Z-stack reveals that the CrvA-GFP filament is only present in the curved part of the cell. Scale bar = 1 μm.

(D) 3D reconstructions of the Z-stack (from 3C) show that CrvA is enriched at the surface of the curved part of the cell. The cell was rotated 43.2° per image for a total of 86.4°.

(E) CrvA enrichment as a function of 3D centerline curvature. Plotted from 3D reconstructions of 80 cells. Average enrichments are displayed as splines through the data along with 90% bootstrap confidence intervals.

(F) Probability densities of the 3D centerline curvature of ΔcrvA and wild-type cells. Each distribution was constructed from 150–300 cells.