Involved in cell shape control. Essential for the development of a rod-shaped cell type required for efficient swimming. In plates, seen throughout the cytoplasm. Localized as spots, short filaments at or near the envelope. In motile rods, localized at or near one or both poles, as spots, short filaments or end-caps, and at mid-cell. Swimming defect. No differences in growth rate or cell size. Belongs to the CetZ family.