<jats:p>
Many motile bacteria employ the flagellar type III secretion system (fT3SS) to construct flagella beyond the cytoplasmic membrane. The C-terminal cytoplasmic domain of FlhA (FlhA
<jats:sub>C</jats:sub>
), a transmembrane subunit of the fT3SS, provides binding sites for export substrates and flagellar export chaperones to coordinate flagellar protein export with assembly.
</jats:p>