Open filament tracks drive Bacteroidota gliding motility

Bacteria in the phylum Bacteroidota move across surfaces using specialized adhesins that attach to the substrate and propel the cell body along an underlying track. Traditionally, it was believed that this track forms a single, closed loop around the cell. However, new research using advanced tracking techniques has revealed significant discrepancies with this prevailing model.

A study employing 3D super-resolution tracking of single adhesin molecules in the bacterium Flavobacterium johnsoniae has challenged the notion of the single closed loop. The data show that adhesins do not follow a consistent, repeating path. Instead, they exhibit non-repeating trajectories that may cross each other, make sharp turns, and exhibit reversals and circular paths.

These findings have led researchers to propose a new model of Bacteroidota gliding. According to this model, the track network is composed of multiple independently moving, open filaments. This supramolecular organization is reminiscent of other moving bacterial filaments such as MreB and FtsZ. The researchers suggest that open filaments may be a common organizing principle in the bacterial cytoskeleton, rather than a single closed loop being the sole mechanism of movement.