MotA and MotB comprise the stator element of the flagellar motor complex. Required for rotation of the flagellar motor. Probable transmembrane proton channel. Overexpression of MotA, with or without MotB, restores motility in a pdeH disruption, (a c-di-GMP phosphodiesterase) suggesting there is an interaction (direct or indirect) between the c-di-GMP-binding flagellar brake protein YcgR and the flagellar stator. Each stator complex is composed of 4 MotA and 2 MotB subunits; in E.coli 11 to 12 stator complexes can be involved in flagellar rotation. 2 A subunits and 1 B subunit are thought to form a single ion channel, so that each stator complex contains two channels. Interacts with FliG. Interacts with flagellar brake protein YcgR in the flagellar basal bodies (PubMed:20303158). In another study (PubMed:20346719) YcgR was not seen to interact with MotA, but instead with FliM and FliG, also in the flagellar basal body. Belongs to the MotA family.