Acts as a flagellar brake, regulating swimming and swarming in a bis-(3'-5') cyclic diguanylic acid (c-di-GMP)-dependent manner. Overexpression of this gene decreases swimming and swarming motility; those cells that are motile turn predominantly counterclockwise. The D-118 mutant is still able to bind FliM but no longer affects motility upon overexpression. Binds 1 c-di-GMP dimer per subunit. Monomer. Interacts with the flagellar basal bodies (By similarity). Localization lost in FliM mutants E-155 or E-160. The N-terminal domain is involved in FliG binding, the C-terminal domain is involved in FliM binding. No visible motility phenotype. Disruption of this gene suppresses the reduced motility of a yhjH disruption, thus the double knockout is motile. Overexpression of this gene in a yhjH disruption has the converse effect, i.e. it reduces motility further. Belongs to the YcgR family.